naive.c File Reference

Source code for naive discrete Legendre transform. More...

#include "s2kit/naive.h"
#include <math.h>
#include <string.h>

Go to the source code of this file.

Functions
void	DLTNaive (double *data, const int bw, const int m, double *weights, double *result, double *pml_table, double *workspace)
	The naive forward discrete Legendre transform. More...
void	InvDLTNaive (double *coeffs, const int bw, const int m, double *result, double *pml_table)
	The inverse discrete Legendre transform. More...

Detailed Description

Source code for naive discrete Legendre transform.

Source code to synthesize functions using a naive DLT based on recurrence. This algorithm is stable and does not require any precomputed functions, but the slowest one.

Definition in file naive.c.

Function Documentation

DLTNaive()

void DLTNaive	(	double *	data,
		const int	bw,
		const int	m,
		double *	weights,
		double *	result,
		double *	pml_table,
		double *	workspace
	)

The naive forward discrete Legendre transform.

Computes the discrete Legendre transform of a function via summing naively. I.e. this is the forward discrete Legendre transform.

Note

See an example of use in test_DLT_naive.c

Parameters

data	array of size 2*bw containing the sample points
bw	bandwidth
m	order
weights	weights for Legendre transform
result	array of size bw-m which will contain the coefficients
pml_table	array of size 2*bw*(bw-m) which contains the precomputed Pmls
workspace	space for computations of size 2*bw

Note

weights should be generated by GenerateWeightsForDLT().

pml_table should be generated by GeneratePmlTable() and contains Legendres with norm equal to 1.

Definition at line 34 of file naive.c.

InvDLTNaive()

void InvDLTNaive	(	double *	coeffs,
		const int	bw,
		const int	m,
		double *	result,
		double *	pml_table
	)

The inverse discrete Legendre transform.

Synthesizes a function from a list of coefficients of a Legendre series. I.e. this is the inverse discrete Legendre transform.

Note

See an example of use in test_DLT_naive.c

Parameters

coeffs	array of size bw-m. The first coefficient is for Pmm
bw	bandwidth
m	order
result	array of size 2*bw which will contain the synthesized function
pml_table	array of size 2*bw*(bw-m) which contains the precomputed Pmls

Note

pml_table should be generated by GeneratePmlTable() and contains Legendres with norm equal to 1.

Definition at line 78 of file naive.c.