las1.h

svd 算法代码 This directory contains instrumented SVDPACKC Version 1.0 (ANSI-C) programs for compiling

/************************************************************** 
 * Sparse svd via eigensystem of equivalent 2-cyclic matrix   *
 * The equivalent symmetric eigenvalue problem:		      *
 *							      *
 *  B x = lambda x, where x' = (u',v'), lambda = +/- sigma,   *
 *							      *
 *      [o  A]						      *
 *  B = [    ] , and A is m (nrow) by n (ncol).		      *
 *	[A' o]						      *
 *							      *
 * global variables and common areas used by las1 and its     *
 * procedures.						      *
 **************************************************************/ 

#define	LMTNW	600000  /* max. size of working area allowed  */
#define	NMAX	3000    /* bound on ncol, order of A   	      */
#define	NZMAX	100000  /* bound on number of nonzeros in A   */

int	ierr,		/* error flag			      */
	j,		/* number of lanczos steps taken      */
	neig,		/* number of ritz values stabilized   */
	nsig,		/* number of accepted ritz values     *
			 * based on kappa (relative accuracy) */
	ncol,		/* number of columns of A	      */
	nrow,		/* number of rows of A		      */
	mxvcount = 0; 

/************************************************************** 
 * pointers to areas holding input matrix which is stored in  *
 * harwell-boeing format.			              *	
 **************************************************************/
int	*pointr = NULL, /* pointer to column start array      */
	*rowind = NULL; /* pointer to row indices array	      */
float  *value = NULL;  /* pointer to nonzero values array    */

float  rnm,		/* norm of the next residual vector   */
	anorm,
	tol,
	eps,		/* positive machine epsilon	      */
	eps1,		/* roundoff estimate for dot product  *
			 * of two unit vector		      */
	reps,
	eps34;

float 	*xv1 = NULL,    /* temp arrays needed for computing   */
	*xv2 = NULL,    /* singular vectors		      */
		
        *a = NULL;	/* pointer to area used by user-      *
			 * supplied procedure store and holds *
			 * lanczos vectors 		      */

FILE	*fp_out1 = NULL;/* output file pointers		      */ 
int	 fp_out2;

char	*error[10] = {  /* error messages used by function    *
			 * check_parameters		      */
	    NULL,	
	  " SORRY, YOUR MATRIX IS TOO BIG ",
	  " ***** ENDL MUST BE LESS THAN ENDR *****",
	  " ***** MAXPRS CANNOT EXCEED LANMAX *****",
	  " ***** N = NROW + NCOL MUST BE GREATER THAN ZERO *****",
	  " ***** LANMAX (NUMBER OF LANCZOS STEPS) IS INVALID *****",
	  " ***** MAXPRS (NUMBER OF IEGENPAIRS DESIRED) IS INVALID *****",
	  " ***** 6*N+4*LANMAX+1 + LANMAX*LANMAX CANNOT EXCEED NW *****",
	  " ***** 6*N+4*LANMAX+1 CANNOT EXCEED NW *****",
	    NULL};