#======================================================================

#                    . . / L I B / L I B A L E C . P L 

#                    doc: Wed Jun  1 20:38:19 2011

#                    dlm: Thu Nov 16 09:20:00 2017

#                    (c) 2011 A.M. Thurnherr

#                    uE-Info: 36 30 NIL 0 0 70 2 2 4 NIL ofnI

#======================================================================

# HISTORY:

#	Nov 15, 2017: - created

require "$ANTS/libvec.pl";

require "$ANTS/libfuns.pl";

#----------------------------------------------------------------------

# User Routines

#----------------------------------------------------------------------

sub ALEC_u($$$$$$$)

{

    my($vx,$vy,$alpha,$compA,$compB,$beta,$magdec) =

		&antsFunUsage(7,'fffffff','<vx[cm/s]> <vy[cm/s]> <alpha> <compA> <compB> <beta>',@_);

	my($c) = ALEC_vel_speed($vx,$vy,$alpha);

	my($d) = ALEC_vel_dir($compA,$compB,$beta,$vx,$vy);

	return vel_u($c,$d-$magdec);

}

sub ALEC_v($$$$$$$)

{

    my($vx,$vy,$alpha,$compA,$compB,$beta,$magdec) =

		&antsFunUsage(7,'fffffff','<vx[cm/s]> <vy[cm/s]> <alpha> <compA> <compB> <beta>',@_);

	my($c) = ALEC_vel_speed($vx,$vy,$alpha);

	my($d) = ALEC_vel_dir($compA,$compB,$beta,$vx,$vy);

	return vel_v($c,$d-$magdec);

}

#------------------------------------------------------------------------------

# Routines mostly as per ALEC manual

#		- weird atan corrections cause data discontinuities

#			=> removed

#		- routines verified with first PITTA time series

# 	ALEC_vel_speed(vx,vy,alpha)

#	ALEC_heading(compA,compB,beta)

# 	ALEC_vel_instrument_dir(vx,vy)

# 	ALEC_vel_dir(compA,compB,beta,vx,vy)

#------------------------------------------------------------------------------

sub ALEC_vel_speed(@)

{

    my($vx,$vy,$alpha) = &antsFunUsage(3,'fff','<vx[cm/s]> <vy[cm/s]> <alpha>',@_);

	my($ssq) = ($vx**2 + $vy**2);

	return inf unless ($ssq > 1e-6);

	return (1 + $alpha*(4*$vx**2*$vy**2)/($ssq**2)) * sqrt($ssq);

}

sub ALEC_heading(@)

{

    my($compA,$compB,$beta) =

        &antsFunUsage(3,'fff','<compass output A> <compass output B> <beta>',@_);

    return angle_pos(deg(atan2($compA,$compB)) + $beta);

}

sub ALEC_vel_instrument_dir($$)

{

    my($vx,$vy) = &antsFunUsage(2,'ff','<vx[cm/s]> <vy[cm/s]>',@_);

	return deg(atan2($vx,$vy));

}

sub ALEC_vel_dir($$$$$)

{

    my($compA,$compB,$beta,$vx,$vy) =

        &antsFunUsage(5,'fffff','<compass output A> <compass output B> <beta> <vx[cm/s]> <vy[cm/s]>',@_);

    return ALEC_heading($compA,$compB,$beta) + ALEC_vel_instrument_dir($vx,$vy);

}

1;