V6.0 release candidate
authorA.M. Thurnherr <athurnherr@yahoo.com>
Thu, 07 May 2015 13:13:22 +0000
changeset 17 4b7486d77b39
parent 15 ebd8a4ddd7f2
child 18 56b72f32a833
V6.0 release candidate
HISTORY
INDEX
libQZ.neardist
libQZ.pl
libSVD.pl
libloopfit.pl
pythag.pl
svbksb.pl
svdcmp.pl
new file mode 100644
--- /dev/null
+++ b/HISTORY
@@ -0,0 +1,11 @@
+#======================================================================
+#                    H I S T O R Y 
+#                    doc: Thu May  7 13:12:05 2015
+#                    dlm: Thu May  7 13:12:52 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 10 10 NIL 0 0 72 0 2 4 NIL ofnI
+#======================================================================
+
+May  7, 2015:
+  - V6.0 [ants.pl] [.hg/hgrc] published for release of LADCPproc V1.2 (Slocum/Explorer processing
+
--- a/INDEX
+++ b/INDEX
@@ -1,9 +1,9 @@
 ======================================================================
                     I N D E X 
                     doc: Wed Jun 18 09:46:58 1997
-                    dlm: Mon Nov  3 12:42:00 2014
+                    dlm: Fri Mar 13 20:55:01 2015
                     (c) 1997 Andreas Thurnherr
-                    uE-Info: 186 41 NIL 0 0 72 2 2 4 NIL ofnI
+                    uE-Info: 195 48 NIL 0 0 72 2 2 4 NIL ofnI
 ======================================================================
 
 NOTES:
@@ -189,7 +189,10 @@
 [libvec.pl]			vector stuff, including distance on globe
 [libWOCE.pl]		WOCE conversions
 
-=Numerical Recipes Routines=
+=Numerical Routines=
+
+[libQZ.pl]			generalized eigenvalue problem (eig(A,B))
+[libSVD.pl]			singular value decomposition
 
 [covsrt.pl]			for [lmfit]
 [fft.pl]			FFT
new file mode 100644
--- /dev/null
+++ b/libQZ.neardist
@@ -0,0 +1,1355 @@
+#======================================================================
+#                    L I B Q Z . P L 
+#                    doc: Thu Mar 12 15:23:15 2015
+#                    dlm: Thu Mar 12 20:52:43 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 36 0 NIL 0 0 72 2 2 4 NIL ofnI
+#======================================================================
+
+# adaptation of EISPACK routines
+
+# www.netlib.org/eispack
+
+sub eig($$)
+{
+	my($aR,$bR) = @_;							# args passed as refs
+
+	my($N) = scalar(@{aR});
+	croak("eig(A,B): A & B must be matching square matrices\n")
+		unless (@{bR} == $N) && (@{$aR->[0]} == $N) && (@{$bR->[0]} == $N);
+
+		ar = new double[n];
+		ai = new double[n];
+		beta = new double[n];
+		var A = (double[,])a.Clone();
+		var B = (double[,])b.Clone();
+
+	my($matZ) = 1;
+	my($iErr) = 0;
+
+	my(@Z);
+	QZhes($aR,$bR,\@Z);								# reduce A/B to upper Hessenberg/triangular forms
+	QZit($aR,$bR,\@Z,\$iErr);						# reduce Hess A to quasi-triangular form
+	QZval($aR,$bR,\@Z,\@alphaR,\@alphaI,\@beta);	# reduce A further
+	QZvec($aR,$bR,\@Z,\@alphaR,\@alphaI,\@beta);	# compute eigenvectors & eigenvalues
+}
+
+
+	/// <summary>Returns the real parts of the alpha values.</summary>
+	public double[] RealAlphas
+	{
+		get { return ar; }
+	}
+
+	/// <summary>Returns the imaginary parts of the alpha values.</summary>
+	public double[] ImaginaryAlphas
+	{
+		get { return ai; }
+	}
+
+	/// <summary>Returns the beta values.</summary>
+	public double[] Betas
+	{
+		get { return beta; }
+	}
+
+	/// <summary>
+	///   Returns true if matrix B is singular.
+	/// </summary>
+	/// <remarks>
+	///   This method checks if any of the generated betas is zero. It
+	///   does not says that the problem is singular, but only that one
+	///   of the matrices of the pencil (A,B) is singular.
+	/// </remarks>
+	public bool IsSingular
+	{
+		get
+		{
+			for (int i = 0; i < n; i++)
+				if (beta[i] == 0)
+					return true;
+			return false;
+		}
+	}
+
+	/// <summary>
+	///   Returns true if the eigenvalue problem is degenerate (ill-posed).
+	/// </summary>
+	public bool IsDegenerate
+	{
+		get
+		{
+			for (int i = 0; i < n; i++)
+				if (beta[i] == 0 && ar[i] == 0)
+					return true;
+			return false;
+		}
+	}
+
+	/// <summary>Returns the real parts of the eigenvalues.</summary>
+	/// <remarks>
+	///   The eigenvalues are computed using the ratio alpha[i]/beta[i],
+	///   which can lead to valid, but infinite eigenvalues.
+	/// </remarks>
+	public double[] RealEigenvalues
+	{
+		get
+		{
+			// ((alfr+i*alfi)/beta)
+			double[] eval = new double[n];
+			for (int i = 0; i < n; i++)
+				eval[i] = ar[i] / beta[i];
+			return eval;
+		}
+	}
+
+	/// <summary>Returns the imaginary parts of the eigenvalues.</summary>  
+	/// <remarks>
+	///   The eigenvalues are computed using the ratio alpha[i]/beta[i],
+	///   which can lead to valid, but infinite eigenvalues.
+	/// </remarks>
+	public double[] ImaginaryEigenvalues
+	{
+		get
+		{
+			// ((alfr+i*alfi)/beta)
+			double[] eval = new double[n];
+			for (int i = 0; i < n; i++)
+				eval[i] = ai[i] / beta[i];
+			return eval;
+		}
+	}
+
+	/// <summary>Returns the eigenvector matrix.</summary>
+	public double[,] Eigenvectors
+	{
+		get
+		{
+			return Z;
+		}
+	}
+
+	/// <summary>Returns the block diagonal eigenvalue matrix.</summary>
+	public double[,] DiagonalMatrix
+	{
+		get
+		{
+			double[,] x = new double[n, n];
+
+			for (int i = 0; i < n; i++)
+			{
+				for (int j = 0; j < n; j++)
+					x[i, j] = 0.0;
+
+				x[i, i] = ar[i] / beta[i];
+				if (ai[i] > 0)
+					x[i, i + 1] = ai[i] / beta[i];
+				else if (ai[i] < 0)
+					x[i, i - 1] = ai[i] / beta[i];
+			}
+
+			return x;
+		}
+	}
+
+
+
+	#region EISPACK Routines
+	/// <summary>
+	///   Adaptation of the original Fortran QZHES routine from EISPACK.
+	/// </summary>
+	/// <remarks>
+	///   This subroutine is the first step of the qz algorithm
+	///   for solving generalized matrix eigenvalue problems,
+	///   siam j. numer. anal. 10, 241-256(1973) by moler and stewart.
+	///
+	///   This subroutine accepts a pair of real general matrices and
+	///   reduces one of them to upper hessenberg form and the other
+	///   to upper triangular form using orthogonal transformations.
+	///   it is usually followed by  qzit,	qzval  and, possibly,  qzvec.
+	///  
+	///   For the full documentation, please check the original function.
+	/// </remarks>
+	private static int qzhes(int n, double[,] a, double[,] b, bool matz, double[,] z)
+	{
+		int i, j, k, l;
+		double r, s, t;
+		int l1;
+		double u1, u2, v1, v2;
+		int lb, nk1;
+		double rho;
+
+
+		if (matz)
+		{
+			// If we are interested in computing the
+			//	eigenvectors, set Z to identity(n,n)
+			for (j = 0; j < n; ++j)
+			{
+				for (i = 0; i < n; ++i)
+					z[i, j] = 0.0;
+				z[j, j] = 1.0;
+			}
+		}
+
+		// Reduce b to upper triangular form
+		if (n <= 1) return 0;
+		for (l = 0; l < n - 1; ++l)
+		{
+			l1 = l + 1;
+			s = 0.0;
+
+			for (i = l1; i < n; ++i)
+				s += (System.Math.Abs(b[i, l]));
+
+			if (s == 0.0) continue;
+			s += (System.Math.Abs(b[l, l]));
+			r = 0.0;
+
+			for (i = l; i < n; ++i)
+			{
+				// Computing 2nd power
+				b[i, l] /= s;
+				r += b[i, l] * b[i, l];
+			}
+
+			r = Special.Sign(System.Math.Sqrt(r), b[l, l]);
+			b[l, l] += r;
+			rho = r * b[l, l];
+
+			for (j = l1; j < n; ++j)
+			{
+				t = 0.0;
+				for (i = l; i < n; ++i)
+					t += b[i, l] * b[i, j];
+				t = -t / rho;
+				for (i = l; i < n; ++i)
+					b[i, j] += t * b[i, l];
+			}
+
+			for (j = 0; j < n; ++j)
+			{
+				t = 0.0;
+				for (i = l; i < n; ++i)
+					t += b[i, l] * a[i, j];
+				t = -t / rho;
+				for (i = l; i < n; ++i)
+					a[i, j] += t * b[i, l];
+			}
+
+			b[l, l] = -s * r;
+			for (i = l1; i < n; ++i)
+				b[i, l] = 0.0;
+		}
+
+		// Reduce a to upper hessenberg form, while keeping b triangular
+		if (n == 2) return 0;
+		for (k = 0; k < n - 2; ++k)
+		{
+			nk1 = n - 2 - k;
+
+			// for l=n-1 step -1 until k+1 do
+			for (lb = 0; lb < nk1; ++lb)
+			{
+				l = n - lb - 2;
+				l1 = l + 1;
+
+				// Zero a(l+1,k)
+				s = (System.Math.Abs(a[l, k])) + (System.Math.Abs(a[l1, k]));
+
+				if (s == 0.0) continue;
+				u1 = a[l, k] / s;
+				u2 = a[l1, k] / s;
+				r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+				v1 = -(u1 + r) / r;
+				v2 = -u2 / r;
+				u2 = v2 / v1;
+
+				for (j = k; j < n; ++j)
+				{
+					t = a[l, j] + u2 * a[l1, j];
+					a[l, j] += t * v1;
+					a[l1, j] += t * v2;
+				}
+
+				a[l1, k] = 0.0;
+
+				for (j = l; j < n; ++j)
+				{
+					t = b[l, j] + u2 * b[l1, j];
+					b[l, j] += t * v1;
+					b[l1, j] += t * v2;
+				}
+
+				// Zero b(l+1,l)
+				s = (System.Math.Abs(b[l1, l1])) + (System.Math.Abs(b[l1, l]));
+
+				if (s == 0.0) continue;
+				u1 = b[l1, l1] / s;
+				u2 = b[l1, l] / s;
+				r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+				v1 = -(u1 + r) / r;
+				v2 = -u2 / r;
+				u2 = v2 / v1;
+
+				for (i = 0; i <= l1; ++i)
+				{
+					t = b[i, l1] + u2 * b[i, l];
+					b[i, l1] += t * v1;
+					b[i, l] += t * v2;
+				}
+
+				b[l1, l] = 0.0;
+
+				for (i = 0; i < n; ++i)
+				{
+					t = a[i, l1] + u2 * a[i, l];
+					a[i, l1] += t * v1;
+					a[i, l] += t * v2;
+				}
+
+				if (matz)
+				{
+					for (i = 0; i < n; ++i)
+					{
+						t = z[i, l1] + u2 * z[i, l];
+						z[i, l1] += t * v1;
+						z[i, l] += t * v2;
+					}
+				}
+			}
+		}
+
+		return 0;
+	}
+
+	/// <summary>
+	///   Adaptation of the original Fortran QZIT routine from EISPACK.
+	/// </summary>
+	/// <remarks>
+	///   This subroutine is the second step of the qz algorithm
+	///   for solving generalized matrix eigenvalue problems,
+	///   siam j. numer. anal. 10, 241-256(1973) by moler and stewart,
+	///   as modified in technical note nasa tn d-7305(1973) by ward.
+	///  
+	///   This subroutine accepts a pair of real matrices, one of them
+	///   in upper hessenberg form and the other in upper triangular form.
+	///   it reduces the hessenberg matrix to quasi-triangular form using
+	///   orthogonal transformations while maintaining the triangular form
+	///   of the other matrix.	it is usually preceded by  qzhes  and
+	///   followed by  qzval  and, possibly,  qzvec.
+	///  
+	///   For the full documentation, please check the original function.
+	/// </remarks>
+	private static int qzit(int n, double[,] a, double[,] b, double eps1, bool matz, double[,] z, ref int ierr)
+	{
+
+		int i, j, k, l = 0;
+		double r, s, t, a1, a2, a3 = 0;
+		int k1, k2, l1, ll;
+		double u1, u2, u3;
+		double v1, v2, v3;
+		double a11, a12, a21, a22, a33, a34, a43, a44;
+		double b11, b12, b22, b33, b34, b44;
+		int na, en, ld;
+		double ep;
+		double sh = 0;
+		int km1, lm1 = 0;
+		double ani, bni;
+		int ish, itn, its, enm2, lor1;
+		double epsa, epsb, anorm = 0, bnorm = 0;
+		int enorn;
+		bool notlas;
+
+
+		ierr = 0;
+
+		#region Compute epsa and epsb
+		for (i = 0; i < n; ++i)
+		{
+			ani = 0.0;
+			bni = 0.0;
+
+			if (i != 0)
+				ani = (Math.Abs(a[i, (i - 1)]));
+
+			for (j = i; j < n; ++j)
+			{
+				ani += Math.Abs(a[i, j]);
+				bni += Math.Abs(b[i, j]);
+			}
+
+			if (ani > anorm) anorm = ani;
+			if (bni > bnorm) bnorm = bni;
+		}
+
+		if (anorm == 0.0) anorm = 1.0;
+		if (bnorm == 0.0) bnorm = 1.0;
+
+		ep = eps1;
+		if (ep == 0.0)
+		{
+			// Use roundoff level if eps1 is zero
+			ep = Special.Epslon(1.0);
+		}
+
+		epsa = ep * anorm;
+		epsb = ep * bnorm;
+		#endregion
+
+
+		// Reduce a to quasi-triangular form, while keeping b triangular
+		lor1 = 0;
+		enorn = n;
+		en = n - 1;
+		itn = n * 30;
+
+	// Begin QZ step
+	L60:
+		if (en <= 1) goto L1001;
+		if (!matz) enorn = en + 1;
+
+		its = 0;
+		na = en - 1;
+		enm2 = na;
+
+	L70:
+		ish = 2;
+		// Check for convergence or reducibility.
+		for (ll = 0; ll <= en; ++ll)
+		{
+			lm1 = en - ll - 1;
+			l = lm1 + 1;
+
+			if (l + 1 == 1)
+				goto L95;
+
+			if ((Math.Abs(a[l, lm1])) <= epsa)
+				break;
+		}
+
+	L90:
+		a[l, lm1] = 0.0;
+		if (l < na) goto L95;
+
+		// 1-by-1 or 2-by-2 block isolated
+		en = lm1;
+		goto L60;
+
+	// Check for small top of b
+	L95:
+		ld = l;
+
+	L100:
+		l1 = l + 1;
+		b11 = b[l, l];
+
+		if (Math.Abs(b11) > epsb) goto L120;
+
+		b[l, l] = 0.0;
+		s = (Math.Abs(a[l, l]) + Math.Abs(a[l1, l]));
+		u1 = a[l, l] / s;
+		u2 = a[l1, l] / s;
+		r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+		v1 = -(u1 + r) / r;
+		v2 = -u2 / r;
+		u2 = v2 / v1;
+
+		for (j = l; j < enorn; ++j)
+		{
+			t = a[l, j] + u2 * a[l1, j];
+			a[l, j] += t * v1;
+			a[l1, j] += t * v2;
+
+			t = b[l, j] + u2 * b[l1, j];
+			b[l, j] += t * v1;
+			b[l1, j] += t * v2;
+		}
+
+		if (l != 0)
+			a[l, lm1] = -a[l, lm1];
+
+		lm1 = l;
+		l = l1;
+		goto L90;
+
+	L120:
+		a11 = a[l, l] / b11;
+		a21 = a[l1, l] / b11;
+		if (ish == 1) goto L140;
+
+		// Iteration strategy
+		if (itn == 0) goto L1000;
+		if (its == 10) goto L155;
+
+		// Determine type of shift
+		b22 = b[l1, l1];
+		if (Math.Abs(b22) < epsb) b22 = epsb;
+		b33 = b[na, na];
+		if (Math.Abs(b33) < epsb) b33 = epsb;
+		b44 = b[en, en];
+		if (Math.Abs(b44) < epsb) b44 = epsb;
+		a33 = a[na, na] / b33;
+		a34 = a[na, en] / b44;
+		a43 = a[en, na] / b33;
+		a44 = a[en, en] / b44;
+		b34 = b[na, en] / b44;
+		t = (a43 * b34 - a33 - a44) * .5;
+		r = t * t + a34 * a43 - a33 * a44;
+		if (r < 0.0) goto L150;
+
+		// Determine single shift zeroth column of a
+		ish = 1;
+		r = Math.Sqrt(r);
+		sh = -t + r;
+		s = -t - r;
+		if (Math.Abs(s - a44) < Math.Abs(sh - a44))
+			sh = s;
+
+		// Look for two consecutive small sub-diagonal elements of a.
+		for (ll = ld; ll + 1 <= enm2; ++ll)
+		{
+			l = enm2 + ld - ll - 1;
+
+			if (l == ld)
+				goto L140;
+
+			lm1 = l - 1;
+			l1 = l + 1;
+			t = a[l + 1, l + 1];
+
+			if (Math.Abs(b[l, l]) > epsb)
+				t -= sh * b[l, l];
+
+			if (Math.Abs(a[l, lm1]) <= (Math.Abs(t / a[l1, l])) * epsa)
+				goto L100;
+		}
+
+	L140:
+		a1 = a11 - sh;
+		a2 = a21;
+		if (l != ld)
+			a[l, lm1] = -a[l, lm1];
+		goto L160;
+
+	// Determine double shift zeroth column of a
+	L150:
+		a12 = a[l, l1] / b22;
+		a22 = a[l1, l1] / b22;
+		b12 = b[l, l1] / b22;
+		a1 = ((a33 - a11) * (a44 - a11) - a34 * a43 + a43 * b34 * a11) / a21 + a12 - a11 * b12;
+		a2 = a22 - a11 - a21 * b12 - (a33 - a11) - (a44 - a11) + a43 * b34;
+		a3 = a[l1 + 1, l1] / b22;
+		goto L160;
+
+	// Ad hoc shift
+	L155:
+		a1 = 0.0;
+		a2 = 1.0;
+		a3 = 1.1605;
+
+	L160:
+		++its;
+		--itn;
+
+		if (!matz) lor1 = ld;
+
+		// Main loop
+		for (k = l; k <= na; ++k)
+		{
+			notlas = k != na && ish == 2;
+			k1 = k + 1;
+			k2 = k + 2;
+
+			km1 = Math.Max(k, l + 1) - 1; // Computing MAX
+			ll = Math.Min(en, k1 + ish);  // Computing MIN
+
+			if (notlas) goto L190;
+
+			// Zero a(k+1,k-1)
+			if (k == l) goto L170;
+			a1 = a[k, km1];
+			a2 = a[k1, km1];
+
+		L170:
+			s = Math.Abs(a1) + Math.Abs(a2);
+			if (s == 0.0) goto L70;
+			u1 = a1 / s;
+			u2 = a2 / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			u2 = v2 / v1;
+
+			for (j = km1; j < enorn; ++j)
+			{
+				t = a[k, j] + u2 * a[k1, j];
+				a[k, j] += t * v1;
+				a[k1, j] += t * v2;
+
+				t = b[k, j] + u2 * b[k1, j];
+				b[k, j] += t * v1;
+				b[k1, j] += t * v2;
+			}
+
+			if (k != l)
+				a[k1, km1] = 0.0;
+			goto L240;
+
+			// Zero a(k+1,k-1) and a(k+2,k-1)
+		L190:
+			if (k == l) goto L200;
+			a1 = a[k, km1];
+			a2 = a[k1, km1];
+			a3 = a[k2, km1];
+
+		L200:
+			s = Math.Abs(a1) + Math.Abs(a2) + Math.Abs(a3);
+			if (s == 0.0) goto L260;
+			u1 = a1 / s;
+			u2 = a2 / s;
+			u3 = a3 / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2 + u3 * u3), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			v3 = -u3 / r;
+			u2 = v2 / v1;
+			u3 = v3 / v1;
+
+			for (j = km1; j < enorn; ++j)
+			{
+				t = a[k, j] + u2 * a[k1, j] + u3 * a[k2, j];
+				a[k, j] += t * v1;
+				a[k1, j] += t * v2;
+				a[k2, j] += t * v3;
+
+				t = b[k, j] + u2 * b[k1, j] + u3 * b[k2, j];
+				b[k, j] += t * v1;
+				b[k1, j] += t * v2;
+				b[k2, j] += t * v3;
+			}
+
+			if (k == l) goto L220;
+			a[k1, km1] = 0.0;
+			a[k2, km1] = 0.0;
+
+		// Zero b(k+2,k+1) and b(k+2,k)
+		L220:
+			s = (Math.Abs(b[k2, k2])) + (Math.Abs(b[k2, k1])) + (Math.Abs(b[k2, k]));
+			if (s == 0.0) goto L240;
+			u1 = b[k2, k2] / s;
+			u2 = b[k2, k1] / s;
+			u3 = b[k2, k] / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2 + u3 * u3), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			v3 = -u3 / r;
+			u2 = v2 / v1;
+			u3 = v3 / v1;
+
+			for (i = lor1; i < ll + 1; ++i)
+			{
+				t = a[i, k2] + u2 * a[i, k1] + u3 * a[i, k];
+				a[i, k2] += t * v1;
+				a[i, k1] += t * v2;
+				a[i, k] += t * v3;
+
+				t = b[i, k2] + u2 * b[i, k1] + u3 * b[i, k];
+				b[i, k2] += t * v1;
+				b[i, k1] += t * v2;
+				b[i, k] += t * v3;
+			}
+
+			b[k2, k] = 0.0;
+			b[k2, k1] = 0.0;
+
+			if (matz)
+			{
+				for (i = 0; i < n; ++i)
+				{
+					t = z[i, k2] + u2 * z[i, k1] + u3 * z[i, k];
+					z[i, k2] += t * v1;
+					z[i, k1] += t * v2;
+					z[i, k] += t * v3;
+				}
+			}
+
+		// Zero b(k+1,k)
+		L240:
+			s = (Math.Abs(b[k1, k1])) + (Math.Abs(b[k1, k]));
+			if (s == 0.0) goto L260;
+			u1 = b[k1, k1] / s;
+			u2 = b[k1, k] / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			u2 = v2 / v1;
+
+			for (i = lor1; i < ll + 1; ++i)
+			{
+				t = a[i, k1] + u2 * a[i, k];
+				a[i, k1] += t * v1;
+				a[i, k] += t * v2;
+
+				t = b[i, k1] + u2 * b[i, k];
+				b[i, k1] += t * v1;
+				b[i, k] += t * v2;
+			}
+
+			b[k1, k] = 0.0;
+
+			if (matz)
+			{
+				for (i = 0; i < n; ++i)
+				{
+					t = z[i, k1] + u2 * z[i, k];
+					z[i, k1] += t * v1;
+					z[i, k] += t * v2;
+				}
+			}
+
+		L260:
+			;
+		}
+
+		goto L70; // End QZ step
+
+	// Set error -- all eigenvalues have not converged after 30*n iterations
+	L1000:
+		ierr = en + 1;
+
+	// Save epsb for use by qzval and qzvec
+	L1001:
+		if (n > 1)
+			b[n - 1, 0] = epsb;
+		return 0;
+	}
+
+	/// <summary>
+	///   Adaptation of the original Fortran QZVAL routine from EISPACK.
+	/// </summary>
+	/// <remarks>
+	///   This subroutine is the third step of the qz algorithm
+	///   for solving generalized matrix eigenvalue problems,
+	///   siam j. numer. anal. 10, 241-256(1973) by moler and stewart.
+	///  
+	///   This subroutine accepts a pair of real matrices, one of them
+	///   in quasi-triangular form and the other in upper triangular form.
+	///   it reduces the quasi-triangular matrix further, so that any
+	///   remaining 2-by-2 blocks correspond to pairs of complex
+	///   eigenvalues, and returns quantities whose ratios give the
+	///   generalized eigenvalues.	it is usually preceded by  qzhes
+	///   and  qzit  and may be followed by  qzvec.
+	///  
+	///   For the full documentation, please check the original function.
+	/// </remarks>
+	private static int qzval(int n, double[,] a, double[,] b, double[] alfr, double[] alfi, double[] beta, bool matz, double[,] z)
+	{
+		int i, j;
+		int na, en, nn;
+		double c, d, e = 0;
+		double r, s, t;
+		double a1, a2, u1, u2, v1, v2;
+		double a11, a12, a21, a22;
+		double b11, b12, b22;
+		double di, ei;
+		double an = 0, bn;
+		double cq, dr;
+		double cz, ti, tr;
+		double a1i, a2i, a11i, a12i, a22i, a11r, a12r, a22r;
+		double sqi, ssi, sqr, szi, ssr, szr;
+
+		double epsb = b[n - 1, 0];
+		int isw = 1;
+
+
+		// Find eigenvalues of quasi-triangular matrices.
+		for (nn = 0; nn < n; ++nn)
+		{
+			en = n - nn - 1;
+			na = en - 1;
+
+			if (isw == 2) goto L505;
+			if (en == 0) goto L410;
+			if (a[en, na] != 0.0) goto L420;
+
+		// 1-by-1 block, one real root
+		L410:
+			alfr[en] = a[en, en];
+			if (b[en, en] < 0.0)
+			{
+				alfr[en] = -alfr[en];
+			}
+			beta[en] = (Math.Abs(b[en, en]));
+			alfi[en] = 0.0;
+			goto L510;
+
+		// 2-by-2 block
+		L420:
+			if (Math.Abs(b[na, na]) <= epsb) goto L455;
+			if (Math.Abs(b[en, en]) > epsb) goto L430;
+			a1 = a[en, en];
+			a2 = a[en, na];
+			bn = 0.0;
+			goto L435;
+
+		L430:
+			an = Math.Abs(a[na, na]) + Math.Abs(a[na, en]) + Math.Abs(a[en, na]) + Math.Abs(a[en, en]);
+			bn = Math.Abs(b[na, na]) + Math.Abs(b[na, en]) + Math.Abs(b[en, en]);
+			a11 = a[na, na] / an;
+			a12 = a[na, en] / an;
+			a21 = a[en, na] / an;
+			a22 = a[en, en] / an;
+			b11 = b[na, na] / bn;
+			b12 = b[na, en] / bn;
+			b22 = b[en, en] / bn;
+			e = a11 / b11;
+			ei = a22 / b22;
+			s = a21 / (b11 * b22);
+			t = (a22 - e * b22) / b22;
+
+			if (Math.Abs(e) <= Math.Abs(ei))
+				goto L431;
+
+			e = ei;
+			t = (a11 - e * b11) / b11;
+
+		L431:
+			c = (t - s * b12) * .5;
+			d = c * c + s * (a12 - e * b12);
+			if (d < 0.0) goto L480;
+
+			// Two real roots. Zero both a(en,na) and b(en,na)
+			e += c + Special.Sign(Math.Sqrt(d), c);
+			a11 -= e * b11;
+			a12 -= e * b12;
+			a22 -= e * b22;
+
+			if (Math.Abs(a11) + Math.Abs(a12) < Math.Abs(a21) + Math.Abs(a22))
+				goto L432;
+
+			a1 = a12;
+			a2 = a11;
+			goto L435;
+
+		L432:
+			a1 = a22;
+			a2 = a21;
+
+		// Choose and apply real z
+		L435:
+			s = Math.Abs(a1) + Math.Abs(a2);
+			u1 = a1 / s;
+			u2 = a2 / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			u2 = v2 / v1;
+
+			for (i = 0; i <= en; ++i)
+			{
+				t = a[i, en] + u2 * a[i, na];
+				a[i, en] += t * v1;
+				a[i, na] += t * v2;
+
+				t = b[i, en] + u2 * b[i, na];
+				b[i, en] += t * v1;
+				b[i, na] += t * v2;
+			}
+
+			if (matz)
+			{
+				for (i = 0; i < n; ++i)
+				{
+					t = z[i, en] + u2 * z[i, na];
+					z[i, en] += t * v1;
+					z[i, na] += t * v2;
+				}
+			}
+
+			if (bn == 0.0) goto L475;
+			if (an < System.Math.Abs(e) * bn) goto L455;
+			a1 = b[na, na];
+			a2 = b[en, na];
+			goto L460;
+
+		L455:
+			a1 = a[na, na];
+			a2 = a[en, na];
+
+		// Choose and apply real q
+		L460:
+			s = System.Math.Abs(a1) + System.Math.Abs(a2);
+			if (s == 0.0) goto L475;
+			u1 = a1 / s;
+			u2 = a2 / s;
+			r = Special.Sign(Math.Sqrt(u1 * u1 + u2 * u2), u1);
+			v1 = -(u1 + r) / r;
+			v2 = -u2 / r;
+			u2 = v2 / v1;
+
+			for (j = na; j < n; ++j)
+			{
+				t = a[na, j] + u2 * a[en, j];
+				a[na, j] += t * v1;
+				a[en, j] += t * v2;
+
+				t = b[na, j] + u2 * b[en, j];
+				b[na, j] += t * v1;
+				b[en, j] += t * v2;
+			}
+
+		L475:
+			a[en, na] = 0.0;
+			b[en, na] = 0.0;
+			alfr[na] = a[na, na];
+			alfr[en] = a[en, en];
+
+			if (b[na, na] < 0.0)
+				alfr[na] = -alfr[na];
+
+			if (b[en, en] < 0.0)
+				alfr[en] = -alfr[en];
+
+			beta[na] = (System.Math.Abs(b[na, na]));
+			beta[en] = (System.Math.Abs(b[en, en]));
+			alfi[en] = 0.0;
+			alfi[na] = 0.0;
+			goto L505;
+
+			// Two complex roots
+		L480:
+			e += c;
+			ei = System.Math.Sqrt(-d);
+			a11r = a11 - e * b11;
+			a11i = ei * b11;
+			a12r = a12 - e * b12;
+			a12i = ei * b12;
+			a22r = a22 - e * b22;
+			a22i = ei * b22;
+
+			if (System.Math.Abs(a11r) + System.Math.Abs(a11i) +
+				System.Math.Abs(a12r) + System.Math.Abs(a12i) <
+				System.Math.Abs(a21) + System.Math.Abs(a22r)
+				+ System.Math.Abs(a22i))
+				goto L482;
+
+			a1 = a12r;
+			a1i = a12i;
+			a2 = -a11r;
+			a2i = -a11i;
+			goto L485;
+
+		L482:
+			a1 = a22r;
+			a1i = a22i;
+			a2 = -a21;
+			a2i = 0.0;
+
+		// Choose complex z
+		L485:
+			cz = System.Math.Sqrt(a1 * a1 + a1i * a1i);
+			if (cz == 0.0) goto L487;
+			szr = (a1 * a2 + a1i * a2i) / cz;
+			szi = (a1 * a2i - a1i * a2) / cz;
+			r = System.Math.Sqrt(cz * cz + szr * szr + szi * szi);
+			cz /= r;
+			szr /= r;
+			szi /= r;
+			goto L490;
+
+		L487:
+			szr = 1.0;
+			szi = 0.0;
+
+		L490:
+			if (an < (System.Math.Abs(e) + ei) * bn) goto L492;
+			a1 = cz * b11 + szr * b12;
+			a1i = szi * b12;
+			a2 = szr * b22;
+			a2i = szi * b22;
+			goto L495;
+
+		L492:
+			a1 = cz * a11 + szr * a12;
+			a1i = szi * a12;
+			a2 = cz * a21 + szr * a22;
+			a2i = szi * a22;
+
+		// Choose complex q
+		L495:
+			cq = System.Math.Sqrt(a1 * a1 + a1i * a1i);
+			if (cq == 0.0) goto L497;
+			sqr = (a1 * a2 + a1i * a2i) / cq;
+			sqi = (a1 * a2i - a1i * a2) / cq;
+			r = System.Math.Sqrt(cq * cq + sqr * sqr + sqi * sqi);
+			cq /= r;
+			sqr /= r;
+			sqi /= r;
+			goto L500;
+
+		L497:
+			sqr = 1.0;
+			sqi = 0.0;
+
+		// Compute diagonal elements that would result if transformations were applied
+		L500:
+			ssr = sqr * szr + sqi * szi;
+			ssi = sqr * szi - sqi * szr;
+			i = 0;
+			tr = cq * cz * a11 + cq * szr * a12 + sqr * cz * a21 + ssr * a22;
+			ti = cq * szi * a12 - sqi * cz * a21 + ssi * a22;
+			dr = cq * cz * b11 + cq * szr * b12 + ssr * b22;
+			di = cq * szi * b12 + ssi * b22;
+			goto L503;
+
+		L502:
+			i = 1;
+			tr = ssr * a11 - sqr * cz * a12 - cq * szr * a21 + cq * cz * a22;
+			ti = -ssi * a11 - sqi * cz * a12 + cq * szi * a21;
+			dr = ssr * b11 - sqr * cz * b12 + cq * cz * b22;
+			di = -ssi * b11 - sqi * cz * b12;
+
+		L503:
+			t = ti * dr - tr * di;
+			j = na;
+
+			if (t < 0.0)
+				j = en;
+
+			r = Math.Sqrt(dr * dr + di * di);
+			beta[j] = bn * r;
+			alfr[j] = an * (tr * dr + ti * di) / r;
+			alfi[j] = an * t / r;
+			if (i == 0) goto L502;
+
+		L505:
+			isw = 3 - isw;
+
+		L510:
+			;
+		}
+
+		b[n - 1, 0] = epsb;
+
+		return 0;
+	}
+
+	/// <summary>
+	///   Adaptation of the original Fortran QZVEC routine from EISPACK.
+	/// </summary>
+	/// <remarks>
+	///   This subroutine is the optional fourth step of the qz algorithm
+	///   for solving generalized matrix eigenvalue problems,
+	///   siam j. numer. anal. 10, 241-256(1973) by moler and stewart.
+	///  
+	///   This subroutine accepts a pair of real matrices, one of them in
+	///   quasi-triangular form (in which each 2-by-2 block corresponds to
+	///   a pair of complex eigenvalues) and the other in upper triangular
+	///   form.  It computes the eigenvectors of the triangular problem and
+	///   transforms the results back to the original coordinate system.
+	///   it is usually preceded by  qzhes,  qzit, and	qzval.
+	///  
+	///   For the full documentation, please check the original function.
+	/// </remarks>
+	private static int qzvec(int n, double[,] a, double[,] b, double[] alfr, double[] alfi, double[] beta, double[,] z)
+	{
+		int i, j, k, m;
+		int na, ii, en, jj, nn, enm2;
+		double d, q;
+		double r = 0, s = 0, t, w, x = 0, y, t1, t2, w1, x1 = 0, z1 = 0, di;
+		double ra, dr, sa;
+		double ti, rr, tr, zz = 0;
+		double alfm, almi, betm, almr;
+
+		double epsb = b[n - 1, 0];
+		int isw = 1;
+
+
+		// for en=n step -1 until 1 do --
+		for (nn = 0; nn < n; ++nn)
+		{
+			en = n - nn - 1;
+			na = en - 1;
+			if (isw == 2) goto L795;
+			if (alfi[en] != 0.0) goto L710;
+
+			// Real vector
+			m = en;
+			b[en, en] = 1.0;
+			if (na == -1) goto L800;
+			alfm = alfr[m];
+			betm = beta[m];
+
+			// for i=en-1 step -1 until 1 do --
+			for (ii = 0; ii <= na; ++ii)
+			{
+				i = en - ii - 1;
+				w = betm * a[i, i] - alfm * b[i, i];
+				r = 0.0;
+
+				for (j = m; j <= en; ++j)
+					r += (betm * a[i, j] - alfm * b[i, j]) * b[j, en];
+
+				if (i == 0 || isw == 2)
+					goto L630;
+
+				if (betm * a[i, i - 1] == 0.0)
+					goto L630;
+
+				zz = w;
+				s = r;
+				goto L690;
+
+			L630:
+				m = i;
+				if (isw == 2) goto L640;
+
+				// Real 1-by-1 block
+				t = w;
+				if (w == 0.0)
+					t = epsb;
+				b[i, en] = -r / t;
+				goto L700;
+
+			// Real 2-by-2 block
+			L640:
+				x = betm * a[i, i + 1] - alfm * b[i, i + 1];
+				y = betm * a[i + 1, i];
+				q = w * zz - x * y;
+				t = (x * s - zz * r) / q;
+				b[i, en] = t;
+				if (Math.Abs(x) <= Math.Abs(zz)) goto L650;
+				b[i + 1, en] = (-r - w * t) / x;
+				goto L690;
+
+			L650:
+				b[i + 1, en] = (-s - y * t) / zz;
+
+			L690:
+				isw = 3 - isw;
+
+			L700:
+				;
+			}
+			// End real vector
+			goto L800;
+
+		// Complex vector
+		L710:
+			m = na;
+			almr = alfr[m];
+			almi = alfi[m];
+			betm = beta[m];
+
+			// last vector component chosen imaginary so that eigenvector matrix is triangular
+			y = betm * a[en, na];
+			b[na, na] = -almi * b[en, en] / y;
+			b[na, en] = (almr * b[en, en] - betm * a[en, en]) / y;
+			b[en, na] = 0.0;
+			b[en, en] = 1.0;
+			enm2 = na;
+			if (enm2 == 0) goto L795;
+
+			// for i=en-2 step -1 until 1 do --
+			for (ii = 0; ii < enm2; ++ii)
+			{
+				i = na - ii - 1;
+				w = betm * a[i, i] - almr * b[i, i];
+				w1 = -almi * b[i, i];
+				ra = 0.0;
+				sa = 0.0;
+
+				for (j = m; j <= en; ++j)
+				{
+					x = betm * a[i, j] - almr * b[i, j];
+					x1 = -almi * b[i, j];
+					ra = ra + x * b[j, na] - x1 * b[j, en];
+					sa = sa + x * b[j, en] + x1 * b[j, na];
+				}
+
+				if (i == 0 || isw == 2) goto L770;
+				if (betm * a[i, i - 1] == 0.0) goto L770;
+
+				zz = w;
+				z1 = w1;
+				r = ra;
+				s = sa;
+				isw = 2;
+				goto L790;
+
+			L770:
+				m = i;
+				if (isw == 2) goto L780;
+
+				// Complex 1-by-1 block
+				tr = -ra;
+				ti = -sa;
+
+			L773:
+				dr = w;
+				di = w1;
+
+				// Complex divide (t1,t2) = (tr,ti) / (dr,di)
+			L775:
+				if (Math.Abs(di) > Math.Abs(dr)) goto L777;
+				rr = di / dr;
+				d = dr + di * rr;
+				t1 = (tr + ti * rr) / d;
+				t2 = (ti - tr * rr) / d;
+
+				switch (isw)
+				{
+					case 1: goto L787;
+					case 2: goto L782;
+				}
+
+			L777:
+				rr = dr / di;
+				d = dr * rr + di;
+				t1 = (tr * rr + ti) / d;
+				t2 = (ti * rr - tr) / d;
+				switch (isw)
+				{
+					case 1: goto L787;
+					case 2: goto L782;
+				}
+
+			   // Complex 2-by-2 block
+			L780:
+				x = betm * a[i, i + 1] - almr * b[i, i + 1];
+				x1 = -almi * b[i, i + 1];
+				y = betm * a[i + 1, i];
+				tr = y * ra - w * r + w1 * s;
+				ti = y * sa - w * s - w1 * r;
+				dr = w * zz - w1 * z1 - x * y;
+				di = w * z1 + w1 * zz - x1 * y;
+				if (dr == 0.0 && di == 0.0)
+					dr = epsb;
+				goto L775;
+
+			L782:
+				b[i + 1, na] = t1;
+				b[i + 1, en] = t2;
+				isw = 1;
+				if (Math.Abs(y) > Math.Abs(w) + Math.Abs(w1))
+					goto L785;
+				tr = -ra - x * b[(i + 1), na] + x1 * b[(i + 1), en];
+				ti = -sa - x * b[(i + 1), en] - x1 * b[(i + 1), na];
+				goto L773;
+
+			L785:
+				t1 = (-r - zz * b[(i + 1), na] + z1 * b[(i + 1), en]) / y;
+				t2 = (-s - zz * b[(i + 1), en] - z1 * b[(i + 1), na]) / y;
+
+			L787:
+				b[i, na] = t1;
+				b[i, en] = t2;
+
+			L790:
+				;
+			}
+
+			// End complex vector
+		L795:
+			isw = 3 - isw;
+
+		L800:
+			;
+		}
+
+		// End back substitution. Transform to original coordinate system.
+		for (jj = 0; jj < n; ++jj)
+		{
+			j = n - jj - 1;
+
+			for (i = 0; i < n; ++i)
+			{
+				zz = 0.0;
+				for (k = 0; k <= j; ++k)
+					zz += z[i, k] * b[k, j];
+				z[i, j] = zz;
+			}
+		}
+
+		// Normalize so that modulus of largest component of each vector is 1.
+		// (isw is 1 initially from before)
+		for (j = 0; j < n; ++j)
+		{
+			d = 0.0;
+			if (isw == 2) goto L920;
+			if (alfi[j] != 0.0) goto L945;
+
+			for (i = 0; i < n; ++i)
+			{
+				if ((Math.Abs(z[i, j])) > d)
+					d = (Math.Abs(z[i, j]));
+			}
+
+			for (i = 0; i < n; ++i)
+				z[i, j] /= d;
+
+			goto L950;
+
+		L920:
+			for (i = 0; i < n; ++i)
+			{
+				r = System.Math.Abs(z[i, j - 1]) + System.Math.Abs(z[i, j]);
+				if (r != 0.0)
+				{
+					// Computing 2nd power
+					double u1 = z[i, j - 1] / r;
+					double u2 = z[i, j] / r;
+					r *= Math.Sqrt(u1 * u1 + u2 * u2);
+				}
+				if (r > d)
+					d = r;
+			}
+
+			for (i = 0; i < n; ++i)
+			{
+				z[i, j - 1] /= d;
+				z[i, j] /= d;
+			}
+
+		L945:
+			isw = 3 - isw;
+
+		L950:
+			;
+		}
+
+		return 0;
+	}
+
+	#endregion
+
+
+
+	#region ICloneable Members
+
+	private GeneralizedEigenvalueDecomposition()
+	{
+	}
+
+	/// <summary>
+	///   Creates a new object that is a copy of the current instance.
+	/// </summary>
+	/// <returns>
+	///   A new object that is a copy of this instance.
+	/// </returns>
+	public object Clone()
+	{
+		var clone = new GeneralizedEigenvalueDecomposition();
+		clone.ai = (double[])ai.Clone();
+		clone.ar = (double[])ar.Clone();
+		clone.beta = (double[])beta.Clone();
+		clone.n = n;
+		clone.Z = (double[,])Z.Clone();
+		return clone;
+	}
+
+	#endregion
+
+}
+
new file mode 100644
--- /dev/null
+++ b/libQZ.pl
@@ -0,0 +1,949 @@
+#======================================================================
+#                    L I B Q Z . P L 
+#                    doc: Thu Mar 12 15:23:15 2015
+#                    dlm: Sun Mar 15 19:26:50 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 14 27 NIL 0 0 72 10 2 4 NIL ofnI
+#======================================================================
+
+# adaptation of EISPACK routines
+# www.netlib.org/eispack
+
+# HISTORY:
+# Mar 12, 2015: - created
+# Mar 15, 2015: - debugging
+
+use strict vars;
+
+my($N);												# size of input matrices A & B
+
+#----------------------------------------------------------------------
+# eig(\@A,\@B,\@evRe,\@evIm,\@V)
+#	- @ev{Re,Im} contain generalized eigenvalues
+#	- @evec contains corresponding right eigenvectors
+#	- A*V = B*V*D, where D is diagonal matrix of eigenvalues
+#----------------------------------------------------------------------
+
+sub eig($$$$$)
+{
+	my($aR,$bR,$erR,$eiR,$zR) = @_;					# args passed as refs
+	my(@alphaR,@alphaI,@beta);						# intermediate data
+
+	$N = scalar(@{$aR});
+	croak(sprintf("eig(A,B): A(%dx%d) & B(%dx%d) must be matching square matrices\n",
+						$N,scalar(@{$aR->[0]}),scalar(@{$bR}),scalar(@{$bR->[0]})))
+		unless (@{$bR} == $N) && (@{$aR->[0]} == $N) && (@{$bR->[0]} == $N);
+
+	QZhes($aR,$bR,$zR);								# reduce A/B to upper Hessenberg/triangular forms
+	croak("QZit(): convergence failed\n")
+		unless (QZit($aR,$bR,$zR) == 0);			# reduce Hess A to quasi-triangular form
+	QZval($aR,$bR,$zR,\@alphaR,\@alphaI,\@beta);	# reduce A further
+	QZvec($aR,$bR,$zR,\@alphaR,\@alphaI,\@beta);	# compute eigenvectors & eigenvalues
+
+	for (my($i)=0; $i<$N; $i++) {
+		if ($beta[$i]==0 && $alphaR[$i]==0) {
+			$erR->[$i] = nan;
+			$eiR->[$i] = nan;
+		} else {
+			$erR->[$i] = $alphaR[$i] / $beta[$i];
+			$eiR->[$i] = $alphaI[$i] / $beta[$i];
+#			print(STDERR "gev[$i] = $erR->[$i]\n");
+		}
+	}
+}
+
+#----------------------------------------------------------------------
+# EISPACK routines
+#----------------------------------------------------------------------
+
+#----------------------------------------------------------------------
+# QZhes(\@A,\@B,\@Z)
+#	- first step in QZ algorithm (Moler & Stewart, SIAM JNA, 1973)
+#----------------------------------------------------------------------
+
+sub QZhes($$$)
+{
+	my($aR,$bR,$zR) = @_;
+	my($i,$j,$k,$l,$l1,$lb,$nk1);	
+	my($r,$s,$t,$u1,$u2,$v1,$v2,$rho);
+
+	croak("QZhes: need at least 3x3 matrices\n")
+		unless ($N >= 2);
+
+	for ($j=0; $j<$N; $j++) {						# init Z to identity matrix
+		for ($i=0; $i<$N; $i++) {
+			$zR->[$i][$j] = 0;
+		}
+		$zR->[$j][$j] = 1;
+    }
+
+	for ($l=0; $l<$N-1; $l++) {
+		$l1 = $l + 1;
+		for ($s=0,$i=$l1; $i<$N; $i++) {
+			$s += abs($bR->[$i][$l]);
+		}
+		next if ($s == 0);
+		$s += abs($bR->[$l][$l]);
+
+		for ($r=0,$i=$l; $i<$N; $i++)
+		{
+			$bR->[$i][$l] /= $s;
+			$r += $bR->[$i][$l]**2;
+		}
+	
+		$r = SIGN(sqrt($r),$bR->[$l][$l]);
+		$bR->[$l][$l] += $r;
+		$rho = $r * $bR->[$l][$l];
+	
+		for ($j=$l1; $j<$N; $j++) {
+			for ($t=0,$i=$l; $i<$N; $i++) {
+				$t += $bR->[$i][$l] * $bR->[$i][$j];
+			}
+			$t = -$t / $rho;
+			for ($i=$l; $i<$N; $i++) {
+				$bR->[$i][$j] += $t * $bR->[$i][$l];
+			}
+		}
+	
+		for ($j=0; $j<$N; $j++) {
+			for ($t=0,$i=$l; $i<$N; $i++) {
+				$t += $bR->[$i][$l] * $aR->[$i][$j];
+			}
+			$t = -$t / $rho;
+			for ($i=$l; $i<$N; $i++) {
+				$aR->[$i][$j] += $t * $bR->[$i][$l];
+			}
+		}
+	
+		$bR->[$l][$l] = -$s * $r;
+		for ($i=$l1; $i<$N; $i++) {
+			$bR->[$i][$l] = 0;
+		}
+	}
+
+	for ($k=0; $k<$N-2; $k++) {
+		$nk1 = $N - 2 - $k;
+
+		for ($lb=0; $lb<$nk1; $lb++) {
+			$l = $N - $lb - 2;
+			$l1 = $l + 1;
+
+			$s = (abs($aR->[$l][$k])) + (abs($aR->[$l1][$k]));
+			next if ($s == 0);
+			
+			$u1 = $aR->[$l][$k] / $s;
+			$u2 = $aR->[$l1][$k] / $s;
+			$r = SIGN(sqrt($u1**2+$u2**2),$u1);
+			$v1 = -($u1 + $r) / $r;
+			$v2 = -$u2 / $r;
+			$u2 = $v2 / $v1;
+	
+			for ($j=$k; $j<$N; $j++) {
+				$t = $aR->[$l][$j] + $u2 * $aR->[$l1][$j];
+				$aR->[$l][$j] += $t * $v1;
+				$aR->[$l1][$j] += $t * $v2;
+			}
+	
+			$aR->[$l1][$k] = 0;
+	
+			for ($j=$l; $j<$N; $j++) {
+				$t = $bR->[$l][$j] + $u2 * $bR->[$l1][$j];
+				$bR->[$l][$j] += $t * $v1;
+				$bR->[$l1][$j] += $t * $v2;
+			}
+	
+			$s = (abs($bR->[$l1][$l1])) + (abs($bR->[$l1][$l]));
+			next if ($s == 0);
+			
+			$u1 = $bR->[$l1][$l1] / $s;
+			$u2 = $bR->[$l1][$l] / $s;
+			$r = SIGN(sqrt($u1**2 + $u2**2),$u1);
+			$v1 = -($u1 + $r) / $r;
+			$v2 = -$u2 / $r;
+			$u2 = $v2 / $v1;
+	
+			for ($i=0; $i<=$l1; $i++) {						# overwrite B with upper triangular form
+				$t = $bR->[$i][$l1] + $u2 * $bR->[$i][$l];
+				$bR->[$i][$l1] += $t * $v1;
+				$bR->[$i][$l] += $t * $v2;
+			}
+			$bR->[$l1][$l] = 0;
+	
+			for ($i=0; $i<$N; $i++) {						# overwrite A with upper Hessenberg form
+				$t = $aR->[$i][$l1] + $u2 * $aR->[$i][$l];
+				$aR->[$i][$l1] += $t * $v1;
+				$aR->[$i][$l] += $t * $v2;
+			}
+	
+			for ($i=0; $i<$N; $i++) {						# define matrix Z, used for eigenvectors
+				$t = $zR->[$i][$l1] + $u2 * $zR->[$i][$l];
+				$zR->[$i][$l1] += $t * $v1;
+				$zR->[$i][$l] += $t * $v2;
+			}
+		} # for ($lb=0; $lb<$nk1; $lb++)
+	} # for ($k=0; $k<$N-2; $k++)
+}
+
+#----------------------------------------------------------------------
+# QZit(\@A,\@B,\@Z)
+#	- second step in QZ algorithm (Moler & Stewart, SIAM JNA, 1973)
+#	- !0 return value indicates that convergence failed
+#----------------------------------------------------------------------
+
+sub QZit($$$$)
+{
+	my($aR,$bR,$zR) = @_;
+
+	my($i,$j,$k);
+	my($r,$s,$t,$a1,$a2);
+	my($k1,$k2,$l1,$ll);
+	my($u1,$u2,$u3);
+	my($v1,$v2,$v3);
+	my($a11,$a12,$a21,$a22,$a33,$a34,$a43,$a44);
+	my($b11,$b12,$b22,$b33,$b34,$b44);
+	my($na,$en,$ld);
+	my($ep,$km1,$ani,$bni);
+	my($ish,$itn,$its,$enm2,$lor1,$epsa,$epsb,$enorn,$notlas);
+	my($l,$a3,$sh,$lm1,$anorm,$bnorm) = (0,0,0,0,0,0);
+
+	for ($i=0; $i<$N; $i++) {
+		$ani = $bni = 0;
+		$ani = abs($aR->[$i][$i-1])
+			unless ($i == 0);
+		for ($j=$i; $j<$N; $j++) {
+			$ani += abs($aR->[$i][$j]);
+			$bni += abs($bR->[$i][$j]);
+		}
+		$anorm = $ani if ($ani > $anorm);
+		$bnorm = $bni if ($bni > $bnorm);
+	}
+	$anorm = 1 if ($anorm == 0);
+	$bnorm = 1 if ($bnorm == 0);
+
+	$ep = 1.11022302462516e-16;	# $EPS=1; $EPS /= 2 while 0.5 + $EPS/2 > 0.5;
+	$epsa = $ep * $anorm;
+	$epsb = $ep * $bnorm;
+
+	$lor1 = 0;
+	$enorn = $N;
+	$en = $N - 1;
+	$itn = $N * 30;
+
+L60:
+	goto L1001 if ($en <= 1);
+	$its = 0;
+	$na = $en - 1;
+	$enm2 = $na;
+
+L70:
+	$ish = 2;
+	for ($ll=0; $ll<=$en; $ll++) {
+		$lm1 = $en - $ll - 1;
+		$l = $lm1 + 1;
+		goto L95 if ($l == 0);
+		last if ((abs($aR->[$l][$lm1])) <= $epsa)
+	}
+
+L90:
+	$aR->[$l][$lm1] = 0;
+	goto L95 if ($l < $na);
+	$en = $lm1;
+	goto L60;
+
+L95:
+	$ld = $l;
+
+L100:
+	$l1 = $l + 1;
+	$b11 = $bR->[$l][$l];
+	goto L120 if (abs($b11) > $epsb);
+	$bR->[$l][$l] = 0;
+	$s = (abs($aR->[$l][$l]) + abs($aR->[$l1][$l]));
+	$u1 = $aR->[$l][$l] / $s;
+	$u2 = $aR->[$l1][$l] / $s;
+	$r = SIGN(sqrt($u1**2 + $u2**2),$u1);
+	$v1 = -($u1 + $r) / $r;
+	$v2 = -$u2 / $r;
+	$u2 = $v2 / $v1;
+
+	for ($j=$l; $j<$enorn; $j++) {
+		$t = $aR->[$l][$j] + $u2 * $aR->[$l1][$j];
+		$aR->[$l][$j] += $t * $v1;
+		$aR->[$l1][$j] += $t * $v2;
+
+		$t = $bR->[$l][$j] + $u2 * $bR->[$l1][$j];
+		$bR->[$l][$j] += $t * $v1;
+		$bR->[$l1][$j] += $t * $v2;
+	}
+	$aR->[$l][$lm1] = -$aR->[$l][$lm1]
+		if ($l != 0);
+		
+	$lm1 = $l;
+	$l = $l1;
+	goto L90;
+
+L120:
+	$a11 = $aR->[$l][$l] / $b11;
+	$a21 = $aR->[$l1][$l] / $b11;
+
+	goto L140 	if ($ish == 1);
+	goto L1000 	if ($itn == 0);
+	goto L155 	if ($its == 10);
+
+	$b22 = $bR->[$l1][$l1];
+	$b22 = $epsb if (abs($b22) < $epsb);
+	$b33 = $bR->[$na][$na];
+	$b33 = $epsb if (abs($b33) < $epsb);
+	$b44 = $bR->[$en][$en];
+	$b44 = $epsb if (abs($b44) < $epsb);
+	
+	$a33 = $aR->[$na][$na] / $b33;
+	$a34 = $aR->[$na][$en] / $b44;
+	$a43 = $aR->[$en][$na] / $b33;
+	$a44 = $aR->[$en][$en] / $b44;
+	$b34 = $bR->[$na][$en] / $b44;
+	
+	$t = ($a43 * $b34 - $a33 - $a44) / 2;
+	$r = $t * $t + $a34 * $a43 - $a33 * $a44;
+	goto L150 if ($r < 0);
+
+	$ish = 1;
+	$r = sqrt($r);
+	$sh = -$t + $r;
+	$s = -$t - $r;
+	$sh = $s if (abs($s-$a44) < abs($sh-$a44));
+
+	for ($ll=$ld; $ll<$enm2; $ll++) {
+		$l = $enm2 + $ld - $ll - 1;
+		goto L140 if ($l == $ld);
+		$lm1 = $l - 1;
+		$l1 = $l + 1;
+		$t = $aR->[$l+1][$l+1];
+		$t -= $sh * $bR->[$l][$l] if (abs($bR->[$l][$l]) > $epsb);
+		goto L100 if (abs($aR->[$l][$lm1]) <= (abs($t / $aR->[$l1][$l])) * $epsa);
+	}
+
+L140:
+	$a1 = $a11 - $sh;
+	$a2 = $a21;
+	$aR->[$l][$lm1] = -$aR->[$l][$lm1] if ($l != $ld);
+	goto L160;
+
+L150:
+	$a12 = $aR->[$l][$l1] / $b22;
+	$a22 = $aR->[$l1][$l1] / $b22;
+	$b12 = $bR->[$l][$l1] / $b22;
+	$a1 = (($a33 - $a11) * ($a44 - $a11) - $a34 * $a43 + $a43 * $b34 * $a11) / $a21 + $a12 - $a11 * $b12;
+	$a2 = $a22 - $a11 - $a21 * $b12 - ($a33 - $a11) - ($a44 - $a11) + $a43 * $b34;
+	$a3 = $aR->[$l1+1][$l] / $b22;
+	goto L160;
+
+L155:
+	$a1 = 0;
+	$a2 = 1;
+	$a3 = 1.1605;
+
+L160:
+	$its++;
+	$itn--;
+	$lor1 = $ld;
+	for ($k=$l; $k<=$na; $k++) {
+
+		$notlas = ($k!=$na) && ($ish==2);
+		$k1 = $k + 1;
+		$k2 = $k + 2;
+		$km1 = MAX($k,$l+1)-1;
+		$ll = MIN($en,$k1+$ish);
+		goto L190 if ($notlas);
+
+		if ($k != $l) {
+			$a1 = $aR->[$k,$km1];
+			$a2 = $aR->[$k1,$km1];
+		}
+
+		$s = abs($a1) + abs($a2);
+		goto L70 if ($s == 0);
+		$u1 = $a1 / $s;
+		$u2 = $a2 / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2), $u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$u2 = $v2 / $v1;
+
+		for ($j=$km1; $j<$enorn; $j++) {
+			$t = $aR->[$k][$j] + $u2 * $aR->[$k1][$j];
+			$aR->[$k][$j] += $t * $v1;
+			$aR->[$k1][$j] += $t * $v2;
+			$t = $bR->[$k][$j] + $u2 * $bR->[$k1][$j];
+			$bR->[$k][$j] += $t * $v1;
+			$bR->[$k1][$j] += $t * $v2;
+		}
+
+		$aR->[$k1,$km1] = 0 if ($k != $l);
+		goto L240;
+
+	L190:
+		goto L200 if ($k == $l);
+		$a1 = $aR->[$k,$km1];
+		$a2 = $aR->[$k1,$km1];
+		$a3 = $aR->[$k2][$km1];
+
+	L200:
+		$s = abs($a1) + abs($a2) + abs($a3);
+		next if ($s == 0);
+		$u1 = $a1 / $s;
+		$u2 = $a2 / $s;
+		$u3 = $a3 / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2 + $u3**2), $u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$v3 = -$u3 / $r;
+		$u2 = $v2 / $v1;
+		$u3 = $v3 / $v1;
+
+		for ($j=$km1; $j<$enorn; $j++) {
+			$t = $aR->[$k][$j] + $u2 * $aR->[$k1][$j] + $u3 * $aR->[$k2][$j];
+			$aR->[$k][$j] += $t * $v1;
+			$aR->[$k1][$j] += $t * $v2;
+			$aR->[$k2][$j] += $t * $v3;
+
+			$t = $bR->[$k][$j] + $u2 * $bR->[$k1][$j] + $u3 * $bR->[$k2][$j];
+			$bR->[$k][$j] += $t * $v1;
+			$bR->[$k1][$j] += $t * $v2;
+			$bR->[$k2][$j] += $t * $v3;
+		}
+
+		goto L220 if ($k == $l);
+		$aR->[$k1,$km1] = $aR->[$k2][$km1] = 0;
+
+	L220:
+		$s = (abs($bR->[$k2][$k2])) + (abs($bR->[$k2][$k1])) + (abs($bR->[$k2][$k]));
+		goto L240 if ($s == 0);
+		$u1 = $bR->[$k2][$k2] / $s;
+		$u2 = $bR->[$k2][$k1] / $s;
+		$u3 = $bR->[$k2][$k] / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2 + $u3**2), $u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$v3 = -$u3 / $r;
+		$u2 = $v2 / $v1;
+		$u3 = $v3 / $v1;
+
+		for ($i=$lor1; $i<$ll+1; $i++) {
+			$t = $aR->[$i][$k2] + $u2 * $aR->[$i][$k1] + $u3 * $aR->[$i][$k];
+			$aR->[$i][$k2] += $t * $v1;
+			$aR->[$i][$k1] += $t * $v2;
+			$aR->[$i][$k] += $t * $v3;
+			$t = $bR->[$i][$k2] + $u2 * $bR->[$i][$k1] + $u3 * $bR->[$i][$k];
+			$bR->[$i][$k2] += $t * $v1;
+			$bR->[$i][$k1] += $t * $v2;
+			$bR->[$i][$k] += $t * $v3;
+		}
+
+		$bR->[$k2][$k] = $bR->[$k2][$k1] = 0;
+
+		for ($i=0; $i<$N; $i++) {
+			$t = $zR->[$i][$k2] + $u2 * $zR->[$i][$k1] + $u3 * $zR->[$i][$k];
+			$zR->[$i][$k2] += $t * $v1;
+			$zR->[$i][$k1] += $t * $v2;
+			$zR->[$i][$k] += $t * $v3;
+		}
+
+	L240:
+		$s = (abs($bR->[$k1][$k1])) + (abs($bR->[$k1][$k]));
+		next if ($s == 0);
+		$u1 = $bR->[$k1][$k1] / $s;
+		$u2 = $bR->[$k1][$k] / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2), $u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$u2 = $v2 / $v1;
+
+		for ($i=$lor1; $i<$ll+1; $i++) {
+			$t = $aR->[$i][$k1] + $u2 * $aR->[$i][$k];
+			$aR->[$i][$k1] += $t * $v1;
+			$aR->[$i][$k] += $t * $v2;
+			$t = $bR->[$i][$k1] + $u2 * $bR->[$i][$k];
+			$bR->[$i][$k1] += $t * $v1;
+			$bR->[$i][$k] += $t * $v2;
+		}
+
+		$bR->[$k1][$k] = 0;
+
+		for ($i=0; $i<$N; $i++) {
+			$t = $zR->[$i][$k1] + $u2 * $zR->[$i][$k];
+			$zR->[$i][$k1] += $t * $v1;
+			$zR->[$i][$k] += $t * $v2;
+		}
+
+	} # for loop beginning at L160
+
+	goto L70; # End QZ step
+
+L1000:										# convergence failure
+	$bR->[$N-1][0] = $epsb;
+	return($en + 1);
+
+L1001:										# convergance okay
+	$bR->[$N-1][0] = $epsb;
+	return 0;
+}
+
+#----------------------------------------------------------------------
+# QZval(\@A,\@B,\@Z,\@alphaR,\@alphaI,\@beta);
+#----------------------------------------------------------------------
+
+sub QZval($$$$$$)
+{
+	my($aR,$bR,$zR,$alfrR,$alfiR,$betaR) = @_;
+	my($i,$j,$na,$en,$nn,$c,$d,$r,$s,$t,$di,$ei);
+	my($a1,$a2,$u1,$u2,$v1,$v2);
+	my($a11,$a12,$a21,$a22,$b11,$b12,$b22);
+	my($bn,$cq,$dr,$cz,$ti,$tr);
+	my($a1i,$a2i,$a11i,$a12i,$a22i,$a11r,$a12r,$a22r);
+	my($sqi,$ssi,$sqr,$szi,$ssr,$szr);
+	my($an,$e,$isw) = (0,0,1);
+	my($epsb) = $bR->[$N-1][0];
+
+	for ($nn=0; $nn<$N; $nn++) {
+		$en = $N - $nn - 1;
+		$na = $en - 1;
+
+		goto L505 if ($isw == 2);
+		goto L410 if ($en == 0);
+		goto L420 if ($aR->[$en][$na] != 0);
+
+	L410:
+		$alfrR->[$en] = ($bR->[$en][$en] < 0) ? -$alfrR->[$en] : $aR->[$en][$en];
+		$betaR->[$en] = (abs($bR->[$en][$en]));
+		$alfiR->[$en] = 0;
+		next;
+
+	L420:
+		goto L455 if (abs($bR->[$na][$na]) <= $epsb);
+		goto L430 if (abs($bR->[$en][$en]) > $epsb);
+		$a1 = $aR->[$en][$en];
+		$a2 = $aR->[$en][$na];
+		$bn = 0;
+		goto L435;
+
+	L430:
+		$an = abs($aR->[$na][$na]) + abs($aR->[$na][$en]) + abs($aR->[$en][$na]) + abs($aR->[$en][$en]);
+		$bn = abs($bR->[$na][$na]) + abs($bR->[$na][$en]) + abs($bR->[$en][$en]);
+		$a11 = $aR->[$na][$na] / $an;
+		$a12 = $aR->[$na][$en] / $an;
+		$a21 = $aR->[$en][$na] / $an;
+		$a22 = $aR->[$en][$en] / $an;
+		$b11 = $bR->[$na][$na] / $bn;
+		$b12 = $bR->[$na][$en] / $bn;
+		$b22 = $bR->[$en][$en] / $bn;
+		$e = $a11 / $b11;
+		$ei = $a22 / $b22;
+		$s = $a21 / ($b11 * $b22);
+		$t = ($a22 - $e * $b22) / $b22;
+
+		goto L431 if (abs($e) <= abs($ei));
+		$e = $ei;
+		$t = ($a11 - $e * $b11) / $b11;
+
+	L431:
+		$c = ($t - $s * $b12) / 2;
+		$d = $c**2 + $s * ($a12 - $e * $b12);
+		goto L480 if ($d < 0);
+
+		$e += $c + SIGN(sqrt($d),$c);
+		$a11 -= $e * $b11;
+		$a12 -= $e * $b12;
+		$a22 -= $e * $b22;
+
+		goto L432 if (abs($a11) + abs($a12) < abs($a21) + abs($a22));
+
+		$a1 = $a12;
+		$a2 = $a11;
+		goto L435;
+
+	L432:
+		$a1 = $a22;
+		$a2 = $a21;
+
+	L435:
+		$s = abs($a1) + abs($a2);
+		$u1 = $a1 / $s;
+		$u2 = $a2 / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2),$u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$u2 = $v2 / $v1;
+
+		for ($i=0; $i<=$en; $i++) {
+			$t = $aR->[$i][$en] + $u2 * $aR->[$i][$na];
+			$aR->[$i][$en] += $t * $v1;
+			$aR->[$i][$na] += $t * $v2;
+
+			$t = $bR->[$i][$e] + $u2 * $bR->[$i][$na];
+			$bR->[$i][$e] += $t * $v1;
+			$bR->[$i][$na] += $t * $v2;
+		}
+
+		for ($i=0; $i<$N; $i++) {
+			$t = $zR->[$i][$en] + $u2 * $zR->[$i][$na];
+			$zR->[$i][$en] += $t * $v1;
+			$zR->[$i][$na] += $t * $v2;
+		}
+
+		goto L475 if ($bn == 0);
+		goto L455 if ($an < abs($e) * $bn);
+		$a1 = $bR->[$na][$na];
+		$a2 = $bR->[$en][$na];
+		goto L460;
+
+	L455:
+		$a1 = $aR->[$na][$na];
+		$a2 = $aR->[$en][$na];
+
+	L460:
+		$s = abs($a1) + abs($a2);
+		goto L475 if ($s == 0);
+		$u1 = $a1 / $s;
+		$u2 = $a2 / $s;
+		$r = SIGN(sqrt($u1**2 + $u2**2),$u1);
+		$v1 = -($u1 + $r) / $r;
+		$v2 = -$u2 / $r;
+		$u2 = $v2 / $v1;
+
+		for ($j=$na; $j<$N; $j++) {
+			$t = $aR->[$na][$j] + $u2 * $aR->[$en][$j];
+			$aR->[$na][$j] += $t * $v1;
+			$aR->[$en][$j] += $t * $v2;
+			$t = $bR->[$na][$j] + $u2 * $bR->[$en][$j];
+			$bR->[$na][$j] += $t * $v1;
+			$bR->[$en][$j] += $t * $v2;
+		}
+
+	L475:
+		$aR->[$en][$na] = $bR->[$en][$na] = 0;
+		$alfrR->[$na] = $aR->[$na][$na];
+		$alfrR->[$en] = $aR->[$en][$en];
+		$alfrR->[$na] = -$alfrR->[$na]
+			if ($bR->[$na][$na] < 0);
+		$alfrR->[$en] = -$alfrR->[$en]
+			if ($bR->[$en][$en] < 0);
+		$betaR->[$na] = (abs($bR->[$na][$na]));
+		$betaR->[$en] = (abs($bR->[$en][$en]));
+		$alfiR->[$en] = $alfiR->[$na] = 0;
+		goto L505;
+
+	L480:
+		$e += $c;
+		$ei = sqrt(-$d);
+		$a11r = $a11 - $e * $b11;
+		$a11i = $ei * $b11;
+		$a12r = $a12 - $e * $b12;
+		$a12i = $ei * $b12;
+		$a22r = $a22 - $e * $b22;
+		$a22i = $ei * $b22;
+
+		goto L482
+			if (abs($a11r) + abs($a11i) + abs($a12r) + abs($a12i) <
+				abs($a21) + abs($a22r) + abs($a22i));
+
+		$a1 = $a12r; 	$a1i = $a12i;
+		$a2 = -$a11r;	$a2i = -$a11i;
+		goto L485;
+
+	L482:
+		$a1 = $a22r;
+		$a1i = $a22i;
+		$a2 = -$a21;
+		$a2i = 0;
+
+	L485:
+		$cz = sqrt($a1**2 + $a1i**2);
+		goto L487 if ($cz == 0);
+		$szr = ($a1 * $a2 + $a1i * $a2i) / $cz;
+		$szi = ($a1 * $a2i - $a1i * $a2) / $cz;
+		$r = sqrt($cz**2 + $szr**2 + $szi**2);
+		$cz /= $r; $szr /= $r; $szi /= $r;
+		goto L490;
+
+	L487:
+		$szr = 1;
+		$szi = 0;
+
+	L490:
+		goto L492 if ($an < (abs($e) + $ei) * $bn);
+		$a1 = $cz * $b11 + $szr * $b12;
+		$a1i = $szi * $b12;
+		$a2 = $szr * $b22;
+		$a2i = $szi * $b22;
+		goto L495;
+
+	L492:
+		$a1 = $cz * $a11 + $szr * $a12;
+		$a1i = $szi * $a12;
+		$a2 = $cz * $a21 + $szr * $a22;
+		$a2i = $szi * $a22;
+
+	L495:
+		$cq = sqrt($a1**2 + $a1i**2);
+		goto L497 if ($cq == 0);
+		$sqr = ($a1 * $a2 + $a1i * $a2i) / $cq;
+		$sqi = ($a1 * $a2i - $a1i * $a2) / $cq;
+		$r = sqrt($cq**2 + $sqr**2 + $sqi**2);
+		$cq /= $r;
+		$sqr /= $r;
+		$sqi /= $r;
+		goto L500;
+
+	L497:
+		$sqr = 1;
+		$sqi = 0;
+
+	L500:
+		$ssr = $sqr * $szr + $sqi * $szi;
+		$ssi = $sqr * $szi - $sqi * $szr;
+		$i = 0;
+		$tr = $cq * $cz * $a11 + $cq * $szr * $a12 + $sqr * $cz * $a21 + $ssr * $a22;
+   		$ti = $cq * $szi * $a12 - $sqi * $cz * $a21 + $ssi * $a22;
+		$dr = $cq * $cz * $b11 + $cq * $szr * $b12 + $ssr * $b22;
+		$di = $cq * $szi * $b12 + $ssi * $b22;
+		goto L503;
+
+	L502:
+		$i = 1;
+		$tr = $ssr * $a11 - $sqr * $cz * $a12 - $cq * $szr * $a21 + $cq * $cz * $a22;
+		$ti = -$ssi * $a11 - $sqi * $cz * $a12 + $cq * $szi * $a21;
+		$dr = $ssr * $b11 - $sqr * $cz * $b12 + $cq * $cz * $b22;
+		$di = -$ssi * $b11 - $sqi * $cz * $b12;
+
+	L503:
+		$t = $ti * $dr - $tr * $di;
+		$j = $na;
+		$j = $en if ($t < 0);
+
+		$r = sqrt($dr**2 + $di**2);
+		$betaR->[$j] = $bn * $r;
+		$alfrR->[$j] = $an * ($tr * $dr + $ti * $di) / $r;
+		$alfiR->[$j] = $an * $t / $r;
+		goto L502 if ($i == 0);
+
+	L505:
+		$isw = 3 - $isw;
+
+	} # main for $nn loop
+
+	$bR->[$N-1][0] = $epsb;
+	return 0;
+}
+
+#----------------------------------------------------------------------
+# QZvec(\@A,\@B,\@Z,\@alphaR,\@alphaI,\@beta)
+#----------------------------------------------------------------------
+
+sub QZvec($$$$$$)
+{
+	my($aR,$bR,$zR,$alfrR,$alfiR,$betaR) = @_;
+	my($i,$j,$k,$m,$na,$ii,$en,$jj,$nn,$enm2,$d,$q,$t,$w,$y,$t1,$t2,$w1,$di);
+	my($ra,$dr,$sa,$ti,$rr,$tr,$alfm,$almi,$betm,$almr);
+	my($r,$s,$x,$x1,$z1,$zz,$isw) = (0,0,0,0,0,0,1);
+	my($epsb) = $bR->[$N-1][0];
+
+	for ($nn=0; $nn<$N; $nn++) {
+		$en = $N - $nn - 1;
+		$na = $en - 1;
+		goto L795 if ($isw == 2);
+		goto L710 if ($alfiR->[$en] != 0);
+
+		$m = $en;
+		$bR->[$en][$en] = 1;
+		next if ($na == -1);
+		$alfm = $alfrR->[$m];
+		$betm = $betaR->[$m];
+
+		for ($ii=0; $ii<=$na; $ii++) {
+			$i = $en - $ii - 1;
+			$w = $betm * $aR->[$i][$i] - $alfm * $bR->[$i][$i];
+			$r = 0;
+
+			for ($j=$m; $j<=$en; $j++) {
+				$r += ($betm * $aR->[$i][$j] - $alfm * $bR->[$i][$j]) * $bR->[$j][$en];
+			}
+
+			goto L630 if ($i == 0 || $isw == 2);
+			goto L630 if ($betm * $aR->[$i,$i-1] == 0);
+
+			$zz = $w;
+			$s = $r;
+			goto L690;
+
+		L630:
+			$m = $i;
+			goto L640 if ($isw == 2);
+
+			$t = $w;
+			$t = $epsb if ($w == 0);
+
+			$bR->[$i][$en] = -$r / $t;
+			next;
+
+		L640:
+			$x = $betm * $aR->[$i][$i+1] - $alfm * $bR->[$i][$i+1];
+			$y = $betm * $aR->[$i+1][$i];
+			$q = $w * $zz - $x * $y;
+			$t = ($x * $s - $zz * $r) / $q;
+			$bR->[$i][$en] = $t;
+			goto L650 if (abs($x) <= abs($zz));
+			$bR->[$i+1][$en] = (-$r - $w * $t) / $x;
+			goto L690;
+
+		L650:
+			$bR->[$i+1][$en] = (-$s - $y * $t) / $zz;
+
+		L690:
+			$isw = 3 - $isw;
+
+		} # for ($ii inner loop
+		next;
+
+	L710:
+		$m = $na;
+		$almr = $alfrR->[$m];
+		$almi = $alfiR->[$m];
+		$betm = $betaR->[$m];
+
+		$y = $betm * $aR->[$en][$na];
+		$bR->[$na][$na] = -$almi * $bR->[$en][$en] / $y;
+		$bR->[$na][$en] = ($almr * $bR->[$en][$en] - $betm * $aR->[$en][$en]) / $y;
+		$bR->[$en][$na] = 0;
+		$bR->[$en][$en] = 1;
+		$enm2 = $na;
+		goto L795 if ($enm2 == 0);
+
+		for ($ii=0; $ii<$enm2; $ii++) {
+			$i = $na - $ii - 1;
+			$w = $betm * $aR->[$i][$i] - $almr * $bR->[$i][$i];
+			$w1 = -$almi * $bR->[$i][$i];
+			$ra = $sa = 0;
+
+			for ($j=$m; j<=$en; $j++) {
+				$x = $betm * $aR->[$i][$j] - $almr * $bR->[$i][$j];
+				$x1 = -$almi * $bR->[$i][$j];
+				$ra = $ra + $x * $bR->[$j][$na] - $x1 * $bR->[$j][$en];
+				$sa = $sa + $x * $bR->[$j][$en] + $x1 * $bR->[$j][$na];
+			}
+
+			goto L770 if ($i == 0 || $isw == 2);
+			goto L770 if ($betm * $aR->[$i,$i-1] == 0);
+
+			$zz = $w; $z1 = $w1;
+			$r = $ra; $s = $sa;
+			$isw = 2;
+			next;
+
+		L770:
+			$m = $i;
+			goto L780 if ($isw == 2);
+			$tr = -$ra; $ti = -$sa;
+
+		L773:
+			$dr = $w; $di = $w1;
+
+		L775:
+			goto L777 if (abs($di) > abs($dr));
+			$rr = $di / $dr;
+			$d = $dr + $di * $rr;
+			$t1 = ($tr + $ti * $rr) / $d;
+			$t2 = ($ti - $tr * $rr) / $d;
+			if    ($isw == 1) { goto L787; }
+			elsif ($isw == 2) { goto L782; }
+
+		L777:
+			$rr = $dr / $di;
+			$d = $dr * $rr + $di;
+			$t1 = ($tr * $rr + $ti) / $d;
+			$t2 = ($ti * $rr - $tr) / $d;
+			if    ($isw == 1) { goto L787; }
+			elsif ($isw == 2) { goto L782; }
+
+		L780:
+			$x = $betm * $aR->[$i][$i+1] - $almr * $bR->[$i][$i+1];
+			$x1 = -$almi * $bR->[$i][$i+1];
+			$y = $betm * $aR->[$i+1][$i];
+			$tr = $y * $ra - $w * $r + $w1 * $s;
+			$ti = $y * $sa - $w * $s - $w1 * $r;
+			$dr = $w * $zz - $w1 * $z1 - $x * $y;
+			$di = $w * $z1 + $w1 * $zz - $x1 * $y;
+			$dr = $epsb if ($dr == 0 && $di == 0);
+			goto L775;
+
+		L782:
+			$bR->[$i+1][$na] = $t1;
+			$bR->[$i+1][$en] = $t2;
+			$isw = 1;
+			goto L785 if (abs($y) > abs($w) + abs($w1));
+			$tr = -$ra - $x * $bR->[$i+1][$na] + $x1 * $bR->[$i+1][$en];
+			$ti = -$sa - $x * $bR->[$i+1][$en] - $x1 * $bR->[$i+1][$na];
+			goto L773;
+
+		L785:
+			$t1 = (-$r - $zz * $bR->[$i+1][$na] + $z1 * $bR->[$i+1][$en]) / $y;
+			$t2 = (-$s - $zz * $bR->[$i+1][$en] - $z1 * $bR->[$i+1][$na]) / $y;
+
+		L787:
+			$bR->[$i][$na] = $t1;
+			$bR->[$i][$en] = $t2;
+
+		} # for ($ii inner loop
+
+	L795:
+		$isw = 3 - $isw;
+
+	} # for ($nn outer loop
+
+	for ($jj=0; $jj<$N; $jj++) {
+		$j = $N - $jj - 1;
+		for ($i=0; $i<$N; $i++) {
+			$zz = 0;
+			for ($k=0; $k<=$j; $k++) {
+				$zz += $zR->[$i][$k] * $bR->[$k][$j];
+			}
+			$zR->[$i][$j] = $zz;
+		}
+	}
+
+	for ($j=0; $j<$N; $j++) {
+		$d = 0;
+		goto L920 if ($isw == 2);
+		goto L945 if ($alfiR->[$j] != 0);
+		for ($i=0; $i<$N; $i++) {
+			$d = (abs($zR->[$i][$j])) if ((abs($zR->[$i][$j])) > $d);
+		}
+		for ($i=0; $i<$N; $i++) {
+			$zR->[$i][$j] /= $d;
+		}
+		next;
+
+	L920:
+		for ($i=0; $i<$N; $i++) {
+			$r = abs($zR->[$i][$j-1]) + abs($zR->[$i][$j]);
+			if ($r != 0) {
+				my($u1) = $zR->[$i][$j-1] / $r;
+				my($u2) = $zR->[$i][$j] / $r;
+				$r *= sqrt($u1**2 + $u2**2);
+			}
+			$d = $r if ($r > $d);
+		}
+
+		for ($i=0; $i<$N; $i++) {
+			$zR->[$i][$j-1] /= $d;
+			$zR->[$i][$j] /= $d;
+		}
+
+	L945:
+		$isw = 3 - $isw;
+
+	} # for ($j outer loop
+}
+
+1;
+
new file mode 100644
--- /dev/null
+++ b/libSVD.pl
@@ -0,0 +1,353 @@
+#======================================================================
+#                    L I B S V D . P L 
+#                    doc: Sat Jul 31 22:47:03 1999
+#                    dlm: Fri Mar 13 20:53:26 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 305 1 NIL 0 0 72 2 2 4 NIL ofnI
+#======================================================================
+
+# HISTORY:
+#	Jul 31, 1999: - created
+#	Jul 19, 2001: - done *something* (message only?)
+#	Mar 11, 2015: - fixed syntax errors (code had never been used before)
+#	Mar 13, 2015: - combined from [sbbksb.pl] [svdcmp.pl] [pythag.pl] [svdfit.pl]
+
+require "$ANTS/nrutil.pl";
+use strict;
+
+#----------------------------------------------------------------------
+# SVBKSB routine from Numerical Recipes adapted to ANTS
+#
+#	solves Ax = b for x, given b
+#
+#	Notes:
+#		- A = U W V' as done in [svdcmp.pl]
+#----------------------------------------------------------------------
+
+sub svbksb($$$$$)
+{
+	my($uR,$wR,$vR,$bR,$xR) = @_;
+	my($jj,$j,$i);									# int
+	my($s);										# float
+	my(@tmp);									# float[]
+
+	&vector(\@tmp,1,$#{$wR});
+	for ($j=1; $j<=$#{$wR}; $j++) {
+		$s = 0;
+		if ($wR->[$j]) {
+			for ($i=1; $i<=$#{$uR}; $i++) {
+				$s += $uR->[$i][$j] * $bR->[$i];
+			}
+			$s /= $wR->[$j];
+		}
+		$tmp[$j]=$s;
+	}
+	for ($j=1; $j<=$#{$wR}; $j++) {
+		$s = 0;
+		for ($jj=1; $jj<=$#{$wR}; $jj++) {
+			$s += $vR->[$j][$jj] * $tmp[$jj];
+		}
+		$xR->[$j] = $s;
+	}
+}
+
+#----------------------------------------------------------------------
+# PYTHAG routine
+#----------------------------------------------------------------------
+
+sub pythag($$)
+{
+	my($a,$b) = @_;							# params
+	my($absa,$absb);						# float 
+
+	$absa = abs($a);
+	$absb = abs($b);
+	return $absa*sqrt(1.0+SQR($absb/$absa))
+		if ($absa > $absb);
+	return ($absb == 0 ? 0 : $absb*sqrt(1+$absa*$absa/$absb/$absb));
+}
+
+
+#----------------------------------------------------------------------
+# SVDCMP routine from Numerical Recipes adapted to ANTS
+#----------------------------------------------------------------------
+
+sub svdcmp($$$)
+{	
+	my($aR,$wR,$vR) = @_;							# params
+	my($flag,$i,$its,$j,$jj,$k,$l,$nm);				# int 
+	my($anorm,$c,$f,$g,$h,$s,$scale,$x,$y,$z);		# float
+	my(@rv1);										# float[]
+
+	vector(\@rv1,1,$#{$vR});
+	$g = $scale = $anorm = 0;
+	for ($i=1; $i<=$#{$vR}; $i++) {
+		$l = $i+1;
+		$rv1[$i] = $scale*$g;
+		$g = $s = $scale = 0;
+		if ($i <= $#{$aR}) {
+			for ($k=$i; $k<=$#{$aR}; $k++) {
+				$scale += abs($aR->[$k][$i]);
+			}
+			if ($scale) {
+				for ($k=$i; $k<=$#{$aR}; $k++) {
+					$aR->[$k][$i] /= $scale;
+					$s += $aR->[$k][$i]*$aR->[$k][$i];
+				}
+				$f = $aR->[$i][$i];
+				$g = -&SIGN(sqrt($s),$f);
+				$h = $f*$g-$s;
+				$aR->[$i][$i] = $f-$g;
+				for ($j=$l; $j<=$#{$vR}; $j++) {
+					for ($s=0,$k=$i; $k<=$#{$aR}; $k++) {
+						$s += $aR->[$k][$i]*$aR->[$k][$j];
+					}
+					$f = $s/$h;
+					for ($k=$i; $k<=$#{$aR}; $k++) {
+						$aR->[$k][$j] += $f*$aR->[$k][$i];
+					}
+				}
+				for ($k=$i; $k<=$#{$aR}; $k++) {
+					$aR->[$k][$i] *= $scale;
+				}
+			}
+		}
+		$wR->[$i] = $scale * $g;
+		$g = 0; $s = 0; $scale = 0;
+		if ($i <= $#{$aR} && $i != $#{$vR}) {
+			for ($k=$l; $k<=$#{$vR}; $k++) {
+				$scale += abs($aR->[$i][$k]);
+			}
+			if ($scale) {
+				for ($k=$l; $k<=$#{$vR}; $k++) {
+					$aR->[$i][$k] /= $scale;
+					$s += $aR->[$i][$k]*$aR->[$i][$k];
+				}
+				$f = $aR->[$i][$l];
+				$g = -&SIGN(sqrt($s),$f);
+				$h = $f*$g-$s;
+				$aR->[$i][$l] = $f-$g;
+				for ($k=$l; $k<=$#{$vR}; $k++) {
+					$rv1[$k] = $aR->[$i][$k]/$h;
+				}
+				for ($j=$l; $j<=$#{$aR}; $j++) {
+					for ($s=0,$k=$l; $k<=$#{$vR}; $k++) {
+						$s += $aR->[$j][$k]*$aR->[$i][$k];
+					}
+					for ($k=$l; $k<=$#{$vR}; $k++) {
+						$aR->[$j][$k] += $s*$rv1[$k];
+					}
+				}
+				for ($k=$l; $k<=$#{$vR}; $k++) {
+					$aR->[$i][$k] *= $scale;
+				}
+			}
+		}
+		$anorm = MAX($anorm,(abs($wR->[$i])+abs($rv1[$i])));
+	}
+	for ($i=$#{$vR}; $i>=1; $i--) {
+		if ($i < $#{$vR}) {
+			if ($g) {
+				for ($j=$l; $j<=$#{$vR}; $j++) {
+					$vR->[$j][$i] = ($aR->[$i][$j]/$aR->[$i][$l])/$g;
+				}
+				for ($j=$l; $j<=$#{$vR}; $j++) {
+					for ($s=0,$k=$l; $k<=$#{$vR}; $k++) {
+						$s += $aR->[$i][$k]*$vR->[$k][$j];
+					}
+					for ($k=$l; $k<=$#{$vR}; $k++) {
+						$vR->[$k][$j] += $s*$vR->[$k][$i];
+					}
+				}
+			}
+			for ($j=$l; $j<=$#{$vR}; $j++) {
+				$vR->[$i][$j] = 0; $vR->[$j][$i] = 0;
+			}
+		}
+		$vR->[$i][$i] = 1;
+		$g = $rv1[$i];
+		$l = $i;
+	}
+	for ($i=MIN($#{$aR},$#{$vR}); $i>=1; $i--) {
+		$l = $i+1;
+		$g = $wR->[$i];
+		for ($j=$l; $j<=$#{$vR}; $j++) {
+			$aR->[$i][$j] = 0;
+		}
+		if ($g) {
+			$g = 1/$g;
+			for ($j=$l; $j<=$#{$vR}; $j++) {
+				for ($s=0,$k=$l; $k<=$#{$aR}; $k++) {
+					$s += $aR->[$k][$i]*$aR->[$k][$j];
+				}
+				$f = ($s/$aR->[$i][$i])*$g;
+				for ($k=$i; $k<=$#{$aR}; $k++) {
+					$aR->[$k][$j] += $f*$aR->[$k][$i];
+				}
+			}
+			for ($j=$i; $j<=$#{$aR}; $j++) {
+				$aR->[$j][$i] *= $g;
+			}
+		} else {
+			for ($j=$i; $j<=$#{$aR}; $j++) {
+				$aR->[$j][$i] = 0;
+			}
+		}
+		++$aR->[$i][$i];
+	}
+	for ($k=$#{$vR}; $k>=1; $k--) {
+		for ($its=1; $its<=30; $its++) {
+			$flag = 1;
+			for ($l=$k; $l>=1; $l--) {
+				$nm = $l-1;
+				if ((abs($rv1[$l])+$anorm) == $anorm) {
+					$flag = 0;
+					last;
+				}
+				last if ($nm == 0) || ((abs($wR->[$nm])+$anorm) == $anorm);	## $nm == 0 test not in original code
+			}
+			if ($flag) {
+				$c = 0;
+				$s = 1;
+				for ($i=$l; $i<=$k; $i++) {
+					$f = $s*$rv1[$i];
+					$rv1[$i] = $c*$rv1[$i];
+					last if ((abs($f)+$anorm) == $anorm);
+					$g = $wR->[$i];
+					$h = &pythag($f,$g);
+					$wR->[$i] = $h;
+					$h = 1/$h;
+					$c = $g*$h;
+					$s = -$f*$h;
+					for ($j=1; $j<=$#{$aR}; $j++) {
+						$y = $aR->[$j][$nm];
+						$z = $aR->[$j][$i];
+						$aR->[$j][$nm] = $y*$c+$z*$s;
+						$aR->[$j][$i] = $z*$c-$y*$s;
+					}
+				}
+			}
+			$z = $wR->[$k];
+			if ($l == $k) {
+				if ($z < 0) {
+					$wR->[$k] = -$z;
+					for ($j=1; $j<=$#{$vR}; $j++) {
+						$vR->[$j][$k] = -$vR->[$j][$k];
+					}
+				}
+#				print(STDERR "its($k) = $its\n");
+				last;
+			}
+			croak("no convergence in 30 svdcmp iterations\n") if ($its == 30);
+			$x = $wR->[$l];
+			$nm = $k-1;
+			$y = $wR->[$nm];
+			$g = $rv1[$nm];
+			$h = $rv1[$k];
+			$f = (($y-$z)*($y+$z)+($g-$h)*($g+$h))/(2.0*$h*$y);
+			$g = &pythag($f,1);
+			$f = (($x-$z)*($x+$z)+$h*(($y/($f+&SIGN($g,$f)))-$h))/$x;
+			$c = 1; $s = 1;
+			for ($j=$l; $j<=$nm; $j++) {
+				$i = $j+1;
+				$g = $rv1[$i];
+				$y = $wR->[$i];
+				$h = $s*$g;
+				$g = $c*$g;
+				$z = &pythag($f,$h);
+				$rv1[$j] = $z;
+				$c = $f/$z;
+				$s = $h/$z;
+				$f = $x*$c+$g*$s;
+				$g = $g*$c-$x*$s;
+				$h = $y*$s;
+				$y *= $c;
+				for ($jj=1; $jj<=$#{$vR}; $jj++) {
+					$x = $vR->[$jj][$j];
+					$z = $vR->[$jj][$i];
+					$vR->[$jj][$j] = $x*$c+$z*$s;
+					$vR->[$jj][$i] = $z*$c-$x*$s;
+				}
+				$z = &pythag($f,$h);
+				$wR->[$j] = $z;
+				if ($z) {
+					$z = 1/$z;
+					$c = $f*$z;
+					$s = $h*$z;
+				}
+				$f = $c*$g+$s*$y;
+				$x = $c*$y-$s*$g;
+				for ($jj=1; $jj<=$#{$aR}; $jj++) {
+					$y = $aR->[$jj][$j];
+					$z = $aR->[$jj][$i];
+					$aR->[$jj][$j] = $y*$c+$z*$s;
+					$aR->[$jj][$i] = $z*$c-$y*$s;
+				}
+			}
+			$rv1[$l] = 0;
+			$rv1[$k] = $f;
+			$wR->[$k] = $x;
+		}
+	}
+}
+
+#----------------------------------------------------------------------
+# SVDFIT routine from Numerical Recipes adapted to ANTS
+#
+# UNTESTED CODE!!!!!
+#
+# Notes:
+#   - x,y,sig are field numbers for data in $ants_
+#   - if sig is a negative number, -sig is used as constant input stddev
+#   - @a, @u, @v, @w, &funcs passed as refs
+#	- chi square is returned
+#----------------------------------------------------------------------
+#
+#{ # BEGIN static scope
+#
+#my($TOL) = 1.0e-5;
+#
+#sub svdfit($$$$$$$$)
+#{
+#	die("untested code");
+#	my($xfnr,$yfnr,$sig,$aR,$uR,$vR,$wR,$funcsR) = @_;
+#	my($j,$i);										# int
+#	my($chisq,$wmax,$tmp,$thresh,$sum);					# float
+#	my(@b,@afunc);									# float[]
+#
+#	&vector(\@b,1,$#ants_);
+#	&vector(\@afunc,1,$#{$aR});
+#	for ($i=0; $i<=$#ants_; $i++) {
+#		next if ($antsFlagged[$i]);
+#		&$funcsR($ants_[$i][$xfnr],\@afunc);
+#		$tmp = 1.0 / (($sig > 0) ? $ants_[$i][$sig] : -$sig);
+#		for ($j=1; $j<=$#{$aR}; $j++) {
+#			$uR->[$i][$j] = $afunc[$j]*$tmp;
+#		}
+#		$b[$i] = $ants_[$i][$yfnr]*$tmp;
+#	}
+#	&svdcmp($uR,$wR,$vR);
+#	for ($j=1; $j<=$#{$aR}; $j++) {
+#		$wmax = $wR->[$j] if ($wR->[$j] > $wmax);
+#	}
+#	$thresh = $TOL*$wmax;
+#	for ($j=1; $j<=$#{$aR}; $j++) {
+#		$wR->[$j] = 0 if ($wR->[$j] < $thresh);
+#	}
+#	&svbksb($uR,$wR,$vR,\@b,$aR);
+#	for ($i=0; $i<=$#ants_; $i++) {
+#		next if ($antsFlagged[$i]);
+#		&$funcsR($ants_[$i][$xfnr],\@afunc);
+#		for ($j=1; $j<=$#{$aR}; $j++) {
+#			$sum += $aR->[$j]*$afunc[$j];
+#		}
+#		$tmp = ($ants_[$i][$yfnr] - $sum) /
+#				(($sig > 0) ? $ants_[$i][$sig] : -$sig);
+#		$chisq += $tmp * $tmp;
+#	}
+#	return $chisq;
+#}
+#
+#} # END static scope
+
+1;
new file mode 100644
--- /dev/null
+++ b/libloopfit.pl
@@ -0,0 +1,114 @@
+#======================================================================
+#                    L I B L O O P F I T . P L 
+#                    doc: Thu Mar 12 08:05:26 2015
+#                    dlm: Sun Mar 15 19:46:49 2015
+#                    (c) 2015 A.M. Thurnherr
+#                    uE-Info: 47 22 NIL 0 0 72 2 2 4 NIL ofnI
+#======================================================================
+
+# HISTORY:
+#	Mar 12, 2015: - created
+#	Mar 15, 2015: - added [libQZ.pl]
+
+require "$ANTS/nrutil.pl";
+require "$ANTS/libSVD.pl";										# for circular fit
+require "$ANTS/libQZ.pl";										# for ellipse fit
+
+#----------------------------------------------------------------------
+# fitCircle(\@x,\@y) => ($r,$cx,$cy)
+#	\@x,\@y		references to list of data values
+#	$r			circle radius
+#	$cx,$cy		circle center
+#----------------------------------------------------------------------
+
+sub fitCircle($$)
+{
+	my($xR,$yR) = @_;
+	my(@A,@V,@W);
+	my($nSamp) = scalar(@{$xR});
+	my($nParam) = 3;
+	
+	matrix(\@A,1,$nSamp,1,$nParam); 							# rows, then columns
+	matrix(\@V,1,$nParam,1,$nParam);							# 3x3 matrix for circle fitting
+	vector(\@W,1,$nParam);										# diag matrix of singular values output as vector
+	vector(\@b,1,$nSamp);										# rhs
+	vector(\@coeff,1,$nParam);									# fit coefficients
+	
+	for ($r=1; $r<=$nSamp; $r++) {								# circle equation c1*x + c2*y + c3 = -(x^2 + y^2)
+		$A[$r][1] = $xR->[$r-1];								#	r  = sqrt((c1^2 + c2^2)/4 - c3)
+		$A[$r][2] = $yR->[$r-1];								#	cx = -c1/2
+		$A[$r][3] = 1;											#	cy = -c2/2
+		$b[$r] = -($xR->[$r-1]**2+$yR->[$r-1]**2);
+	}
+	
+	svdcmp(\@A,\@W,\@V);										# solve Ax = b, with x == coeff
+	svbksb(\@A,\@W,\@V,\@b,\@coeff);
+	
+	return ($coeff[1],$coeff[2],$coeff[3]);
+	my($r)	= sqrt(($coeff[1]**2+$coeff[2]**2)/4-$coeff[3]);
+	my($cx) = -0.5*$coeff[1];
+	my($cy) = -0.5*$coeff[2];
+	return ($r,$cx,$cy);
+}
+
+#----------------------------------------------------------------------
+# fitEllipse(\@x,\@y) => ?
+#	\@x,\@y		references to list of data values
+#
+#	Direct Least Square Fitting of Ellipses
+#	Andrew Fitzgibbon, Maurizio Pilu, and Robert B. Fisher, MAY 1999
+# 	IEEE transactions on pattern analysis and machine intelligence 21(5): 476-480
+#----------------------------------------------------------------------
+
+sub fitEllipse($$)
+{
+	my($xR,$yR) = @_;
+	my($nSamp) = scalar(@{$xR});
+	
+	# design matrix D = [ x.*x x.*y y.*y x y ones(size(x)) ]; 
+	my(@D);
+	for (my($r)=0; $r<$nSamp; $r++) {
+		$D[$r][0] = $xR->[$r]**2;
+		$D[$r][1] = $xR->[$r] * $yR->[$r];
+		$D[$r][2] = $yR->[$r]**2;
+		$D[$r][3] = $xR->[$r];
+		$D[$r][4] = $yR->[$r];
+		$D[$r][5] = 1;
+	}
+
+	# scatter matrix S = D' * D;
+	my(@S);
+	for (my($i)=0; $i<6; $i++) {
+		for (my($j)=0; $j<6; $j++) {
+			for (my($k)=0; $k<$nSamp; $k++) {
+				$S[$i][$j] += $D[$k][$j] * $D[$k][$i];
+			}
+		}
+	}
+
+	# 6x6 constraint matrix C
+	my(@C);
+	for (my($r)=0; $r<6; $r++) {
+		for (my($c)=0; $c<6; $c++) {
+			$C[$r][$c] = 0;
+		}
+	}
+	$C[0][2] = -2; $C[1][1] = 1; $C[2][0] = -2;
+
+	# solve generalized eigensystem
+	my(@geRe,@geImg,@geVec);
+	eig(\@S,\@C,\@geRe,\@geImg,\@geVec);
+
+	# find only negative eigenvalue
+	my($i);
+	for ($i=0; $i<@geRe; $i++) {
+		last if (numberp($geRe[$i]) && ($geRe[$i] < 0));
+	}
+	croak("internal error") unless ($geRe[$i] < 0);
+
+	# get fitted parameters
+	return @{$geVec[$i]};
+
+}
+
+1;
--- a/pythag.pl
+++ b/pythag.pl
@@ -1,15 +1,16 @@
 #======================================================================
-#                    . / P Y T H A G . P L 
+#                    P Y T H A G . P L 
 #                    doc: Sun Aug  1 10:41:34 1999
-#                    dlm: Sun Aug  1 10:46:43 1999
+#                    dlm: Wed Mar 11 14:53:21 2015
 #                    (c) 1999 A.M. Thurnherr
-#                    uE-Info: 23 65 NIL 0 0 72 0 2 4 ofnI
+#                    uE-Info: 27 2 NIL 0 0 72 0 2 4 NIL ofnI
 #======================================================================
 
 # PYTHAG routine from Numerical Recipes adapted to ANTS
 
 # HISTORY:
 #	Aug 01, 1999: - manually converted from c-source
+#	Mar 11, 2015: - BUG: syntax errors (code had never been used)
 
 sub pythag($$)
 {
@@ -20,6 +21,7 @@
 	$absb = abs($b);
 	return $absa*sqrt(1.0+SQR($absb/$absa))
 		if ($absa > $absb);
-	return ($absb == 0 ? 0 : $absb*sqrt(1+$absa*$absa/$absb/$absb)));
+	return ($absb == 0 ? 0 : $absb*sqrt(1+$absa*$absa/$absb/$absb));
 }
 
+1;
--- a/svbksb.pl
+++ b/svbksb.pl
@@ -1,21 +1,26 @@
 #======================================================================
-#                    . / S V B K S B . P L 
+#                    S V B K S B . P L 
 #                    doc: Sat Jul 31 22:47:03 1999
-#                    dlm: Sat Jul 31 23:06:40 1999
+#                    dlm: Wed Mar 11 19:29:39 2015
 #                    (c) 1999 A.M. Thurnherr
-#                    uE-Info: 30 32 NIL 0 0 72 2 2 4 ofnI
+#                    uE-Info: 20 0 NIL 0 0 72 2 2 4 NIL ofnI
 #======================================================================
 
 # SVBKSB routine from Numerical Recipes adapted to ANTS
+#
+#	solves Ax = b for x, given b
+#
+#	Notes:
+#		- A = U W V' as done in [svdcmp.pl]
 
 # HISTORY:
 #	Jul 31, 1999: - manually converted from c-source
-
-# Notes:
-#   - everything passed as refs
+#	Mar 11, 2015: - fixed syntax errors (code had never been used before)
 
 require "$ANTS/nrutil.pl";
 
+use strict;
+
 sub svbksb($$$$$)
 {
 	my($uR,$wR,$vR,$bR,$xR) = @_;
@@ -37,9 +42,9 @@
 	for ($j=1; $j<=$#{$wR}; $j++) {
 		$s = 0;
 		for ($jj=1; $jj<=$#{$wR}; $jj++) {
-			$s += $vR->[$j][$jj] * tmp[$jj];
+			$s += $vR->[$j][$jj] * $tmp[$jj];
 		}
-		$x->[$j] = $s;
+		$xR->[$j] = $s;
 	}
 }
 
--- a/svdcmp.pl
+++ b/svdcmp.pl
@@ -1,15 +1,18 @@
 #======================================================================
 #                    S V D C M P . P L 
 #                    doc: Sun Aug  1 09:51:37 1999
-#                    dlm: Thu Jul 19 09:45:52 2001
+#                    dlm: Wed Mar 11 16:54:26 2015
 #                    (c) 1999 A.M. Thurnherr
-#                    uE-Info: 184 18 NIL 0 0 72 2 2 4 NIL ofnI
+#                    uE-Info: 188 1 NIL 0 0 72 10 2 4 NIL ofnI
 #======================================================================
 
 # SVDCMP routine from Numerical Recipes adapted to ANTS
 
 # HISTORY:
 #	Aug 01, 1999: - manually converted from c-source
+#	Jul 19, 2001: - done *something* (message only?)
+#	Mar 11, 2015: - picked up this never-used code because of need to fit circles
+
 
 # Notes:
 #   - everything passed as refs
@@ -17,18 +20,21 @@
 require "$ANTS/nrutil.pl";
 require "$ANTS/pythag.pl";
 
+use strict;
+
 sub svdcmp($$$)
-{
+{	
 	my($aR,$wR,$vR) = @_;							# params
 	my($flag,$i,$its,$j,$jj,$k,$l,$nm);				# int 
 	my($anorm,$c,$f,$g,$h,$s,$scale,$x,$y,$z);		# float
 	my(@rv1);										# float[]
 
 	vector(\@rv1,1,$#{$vR});
+	$g = $scale = $anorm = 0;
 	for ($i=1; $i<=$#{$vR}; $i++) {
 		$l = $i+1;
 		$rv1[$i] = $scale*$g;
-		$g = 0; $s = 0; $scale = 0;
+		$g = $s = $scale = 0;
 		if ($i <= $#{$aR}) {
 			for ($k=$i; $k<=$#{$aR}; $k++) {
 				$scale += abs($aR->[$k][$i]);
@@ -87,7 +93,7 @@
 				}
 			}
 		}
-		$anorm = &FMAX($anorm,(abs($wR->[$i])+abs($rv1[$i])));
+		$anorm = MAX($anorm,(abs($wR->[$i])+abs($rv1[$i])));
 	}
 	for ($i=$#{$vR}; $i>=1; $i--) {
 		if ($i < $#{$vR}) {
@@ -104,7 +110,7 @@
 					}
 				}
 			}
-			for ($j=$l; $j<=$#{$vR; $j++) {
+			for ($j=$l; $j<=$#{$vR}; $j++) {
 				$vR->[$i][$j] = 0; $vR->[$j][$i] = 0;
 			}
 		}
@@ -112,7 +118,7 @@
 		$g = $rv1[$i];
 		$l = $i;
 	}
-	for ($i=IMIN($#{$aR},$#{$vR}); $i>=1; $i--) {
+	for ($i=MIN($#{$aR},$#{$vR}); $i>=1; $i--) {
 		$l = $i+1;
 		$g = $wR->[$i];
 		for ($j=$l; $j<=$#{$vR}; $j++) {
@@ -146,9 +152,9 @@
 				$nm = $l-1;
 				if ((abs($rv1[$l])+$anorm) == $anorm) {
 					$flag = 0;
-					break;
+					last;
 				}
-				break if ((abs($wR->[$nm])+$anorm) == $anorm);
+				last if ($nm == 0) || ((abs($wR->[$nm])+$anorm) == $anorm);	## $nm == 0 test not in original code
 			}
 			if ($flag) {
 				$c = 0;
@@ -156,7 +162,7 @@
 				for ($i=$l; $i<=$k; $i++) {
 					$f = $s*$rv1[$i];
 					$rv1[$i] = $c*$rv1[$i];
-					break if ((abs($f)+$anorm) == $anorm);
+					last if ((abs($f)+$anorm) == $anorm);
 					$g = $wR->[$i];
 					$h = &pythag($f,$g);
 					$wR->[$i] = $h;
@@ -179,7 +185,8 @@
 						$vR->[$j][$k] = -$vR->[$j][$k];
 					}
 				}
-				break;
+#				print(STDERR "its($k) = $its\n");
+				last;
 			}
 			croak("no convergence in 30 svdcmp iterations\n") if ($its == 30);
 			$x = $wR->[$l];