?lascl

Perform scalar operations on a matrix.

Interface Definition

C interface:

void slascl_(const char *type, const int *kl, const int *ku, const float *cfrom, const float *cto, const int *m, const int *n, float *a, const int *lda, int *info);

void dlascl_(const char *type, const int *kl, const int *ku, const double *cfrom, const double *cto, const int *m, const int *n, double *a, const int *lda, int *info);

void clascl_(const char *type, const int *kl, const int *ku, const float *cfrom, const float *cto, const int *m, const int *n, float _Complex *a, const int *lda, int *info);

void zlascl_(const char *type, const int *kl, const int *ku, const double *cfrom, const double *cto, const int *m, const int *n, double _Complex *a, const int *lda, int *info);

Fortran interface:

SLASCL(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO);

DLASCL(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO);

CLASCL(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO);

ZLASCL(TYPE, KL, KU, CFROM, CTO, M, N, A, LDA, INFO);

Parameters

Parameter	Type	Description	Input/Output
TYPE	Character	'G': Matrix A is a full matrix. 'L': Matrix A is a lower triangular matrix. 'U': Matrix A is an upper triangular matrix. 'H': Matrix A is an upper Hessenberg matrix. 'B': Matrix A is a symmetric band matrix whose lower bandwidth is KL and upper bandwidth is KU. It only stores the part below the diagonal 'Q': Matrix A is a symmetric band matrix whose lower bandwidth is KL and upper bandwidth is KU. It only stores the part above the diagonal 'Z': Matrix A is a band matrix whose lower bandwidth is KL and upper bandwidth is KU.	Input
KL	Integer	Lower bandwidth of matrix A. This parameter is valid when TYPE is 'B', 'Q', or 'Z'.	Input
KU	Integer	Upper bandwidth of matrix A. This parameter is valid when TYPE is 'B', 'Q', or 'Z'.	Input
CFROM	Single-precision floating-point type for slascl Double-precision floating-point type for dlascl Single-precision floating-point type for clascl Double-precision floating-point type for zlascl	Denominator of the scalar value, that is, scalar = CTO/CFROM. It cannot be zero.	Input
CTO	Single-precision floating-point type for slascl Double-precision floating-point type for dlascl Single-precision floating-point type for clascl Double-precision floating-point type for zlascl	Numerator of the scalar value, that is, scalar = CTO/CFROM.	Input
M	Integer	Number of rows in matrix A, M ≥ 0.	Input
N	Integer	Number of columns in matrix A, N ≥ 0.	Input
A	A single-precision floating-point array for slascl A double-precision floating-point array for dlascl A complex single-precision array for clascl A complex double-precision array for zlascl	Matrix A, with a dimension of (LDA, N).	Input, output
LDA	Integer	Leading dimension of matrix A. If TYPE='G', 'L', 'U', or 'H', LDA≥max(1, M). If TYPE='B', LDA≥KL+1. If TYPE='Q', LDA≥KU+1. If TYPE='Z', LDA≥2*KL+KU+1.	Input
INFO	Integer	0: The execution is successful. Smaller than 0: The value of the -info-th parameter is invalid.	Output

Dependency

#include "klapack.h"

Examples

C interface:

const char type = 'G';
const int n = 4;
const int m = 4;
const int kl = 2;
const int ku = 2;
const double cfrom = 2.0;
const double cto = 1.0;
const int lda = m;
int info = 0;

double a[] = {1.0, 1.0, 1.0, 1.0,
              2.0, 2.0, 2.0, 2.0,
              3.0, 3.0, 3.0, 3.0,
              4.0, 4.0, 4.0, 4.0};

dlascl_(&type, &kl, &ku, &cfrom, &cto, &m, &n, a, &lda, &info);
/* 
 * Output: 
 * a output
 *   
 *  0.500000        0.500000        0.500000        0.500000
 *  1.000000        1.000000        1.000000        1.000000
 *  1.500000        1.500000        1.500000        1.500000
 *  2.000000        2.000000        2.000000        2.000000

Fortran interface:

CHARACTER :: type = "G"
PARAMETER (m = 4) 
PARAMETER (n = 4)
PARAMETER (kl = 2)
PARAMETER (ku = 2)
PARAMETER (lda = 4) 
REAL(8) :: cfrom
REAL(8) :: cto
REAL(8) :: a(lda, n)  
  
DATA cfrom / 2.0 / 
DATA cto / 1.0 /
DATA a / 1.0, 1.0, 1.0, 1.0,
         2.0, 2.0, 2.0, 2.0,
         3.0, 3.0, 3.0, 3.0,
         4.0, 4.0, 4.0, 4.0 /
 EXTERNAL DLASCL
 CALL DLASCL(type, kl, ku, cfrom, cto, m, n, a, lda, info);
* 
* Output: 
* a output
*  
*  0.500000        0.500000        0.500000        0.500000
*  1.000000        1.000000        1.000000        1.000000
*  1.500000        1.500000        1.500000        1.500000
*  2.000000        2.000000        2.000000        2.000000

Parent topic: Auxiliary Functions