fast1_transform.c File Reference

Perform the fast1 spherical harmonic transform. More...

#include "libftsh.h"

Defines
#define	ENTEREXIT   0
Functions
void	Pm_1d_analyse (REAL *outcoef, Pm_1D *inmat, REAL *infcn, Pm_1D_Workspace *pmnwork)
void	Pm_1d_synthesize (REAL *outfcn, Pm_1D *inmat, REAL *incoef, Pm_1D_Workspace *pmnwork)

---

Detailed Description

Perform the fast1 spherical harmonic transform.

Summary:

• Pm_1d_analyse transforms function values to coefficients.
• Pm_1d_synthesize transforms coefficients to function values.

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Function Documentation

void Pm_1d_analyse	(	REAL *	outcoef,
		Pm_1D *	inmat,
		REAL *	infcn,
		Pm_1D_Workspace *	pmnwork
	)

Expands (analyses) a function into spherical harmonic coefficients.

This routine only does one order (m) so it is really only an Associaded Legendre Function analyser.

INPUTS:

• inmat -- The precomuted matrix of Associated Legendre functions of the desired order in compressed Pm_1D format
• infcn -- an array of REALs to hold the function to expand. Its length is encoded in the number of columns in inmat.
• pmnwork -- a structure that holds workspace and a few global precomputed values.

OUTPUTS: outcoef -- an array of the coefficients computed. The information on how many of these to compute is encoded by the number of rows in inmat.

NOTES:

• We could check that (numbas[0]==numbas[1])||(numbas[0]==numbas[1]+1)
• ?UNROLL the parity LOOP ONCE DEBUGGED?

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void Pm_1d_synthesize	(	REAL *	outfcn,
		Pm_1D *	inmat,
		REAL *	incoef,
		Pm_1D_Workspace *	pmnwork
	)

Evaluates (synthesizes) a function from spherical harmonic coefficients.

This routine only does one order (m) so it is really only an Associaded Legendre Function synthesizer.

INPUTS:

• inmat -- The precomuted matrix of Associated Legendre functions of the desired order in compressed Pm_1D format
• incoef -- an array of the coefficients to use. The information on how many of these to use is encoded by the number of rows in inmat.
• pmnwork -- a structure that holds workspace and a few global precomputed values

OUTPUTS: outfcn -- an array of REALs to hold the computed function. Its length is encoded in the number of columns in inmat.

NOTES:

• we could check that (numbas[0]==numbas[1])||(numbas[0]==numbas[1]+1)

Here is the call graph for this function: