#include <stdlib.h>
#include <math.h>
#include "include/hholder.h"

Include dependency graph for hholder.c:

Functions
double	householder_transform (double vector, int N, double help)
int	householder_hm (double tau, double vector, double *matrix, int rowNr, int columnNr)
int	householder_hv (double tau, int size, double v, double w)
double	householder_norm (double *v, int size)

Function Documentation

int householder_hm	(	double	tau,
		double *	vector,
		double **	matrix,
		int	rowNr,
		int	columnNr
	)

applies a householder transformation defined by vector "vector" and scalar tau to the left-hand side of the matrix. (I - tau vector vector^T)*matrix The result of the transform is stored in matrix.

Returns:: Returns 0 if ok.

Parameters:

tau	Coefficient defining householder transform
vector	Vector defining householder transform
matrix	the matrix that is to be transformed
rowNr	Nr of rows in matrix
columnNr	Nr of columns in matrix

Definition at line 97 of file hholder.c.

Referenced by qr_decomp().

int householder_hv	(	double	tau,
		int	size,
		double *	v,
		double *	w
	)

applies a householder transformation defined by vector v and coeffiecient tau to vector w w = (I - tau v v^T) w

Returns:: Returns 0 if ok.

Definition at line 155 of file hholder.c.

Referenced by qr_QTvec(), and qr_Qvec().

double householder_norm	(	double *	v,
		int	size
	)

Returns the euclidean norm of a vector

Definition at line 193 of file hholder.c.

Referenced by householder_transform().

double householder_transform	(	double *	vector,
		int	N,
		double *	help
	)

This function prepares a Householder transformation P = I - tau h h^T which can be used to zero all the elements of the input vector except the first one that will get value beta. On output the elements 1 - size-1 of the vector h are stored in locations vector[1] - vector[size-1] of the input vector and value of beta is stored in location vector[0].

Returns:: The scalar tau is returned.

Parameters:

vector	The N-vector to be transformed
N	size of the vector
help	N-array of working space

Definition at line 36 of file hholder.c.

References householder_norm().

Referenced by qr_decomp().

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Functions

Function Documentation