Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 6/24/2024
Public

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?lascl

Multiplies a general rectangular matrix by a real scalar defined as cto/cfrom.

Syntax

call slascl( type, kl, ku, cfrom, cto, m, n, a, lda, info )

call dlascl( type, kl, ku, cfrom, cto, m, n, a, lda, info )

call clascl( type, kl, ku, cfrom, cto, m, n, a, lda, info )

call zlascl( type, kl, ku, cfrom, cto, m, n, a, lda, info )

Include Files

  • mkl.fi

Description

The routine ?lascl multiplies the m-by-n real/complex matrix A by the real scalar cto/cfrom. The operation is performed without over/underflow as long as the final result cto*A(i,j)/cfrom does not over/underflow.

type specifies that A may be full, upper triangular, lower triangular, upper Hessenberg, or banded.

Input Parameters

type

CHARACTER*1. This parameter specifies the storage type of the input matrix.

= 'G': A is a full matrix.

= 'L': A is a lower triangular matrix.

= 'U': A is an upper triangular matrix.

= 'H': A is an upper Hessenberg matrix.

= 'B': A is a symmetric band matrix with lower bandwidth kl and upper bandwidth ku and with the only the lower half stored

= 'Q': A is a symmetric band matrix with lower bandwidth kl and upper bandwidth ku and with the only the upper half stored.

= 'Z': A is a band matrix with lower bandwidth kl and upper bandwidth ku. See description of the ?gbtrf function for storage details.

kl

INTEGER. The lower bandwidth of A. Referenced only if type = 'B', 'Q' or 'Z'.

ku

INTEGER. The upper bandwidth of A. Referenced only if type = 'B', 'Q' or 'Z'.

cfrom, cto

REAL for slascl/clascl

DOUBLE PRECISION for dlascl/zlascl

The matrix A is multiplied by cto/cfrom. A(i,j) is computed without over/underflow if the final result cto*A(i,j)/cfrom can be represented without over/underflow. cfrom must be nonzero.

m

INTEGER. The number of rows of the matrix A. m 0.

n

INTEGER. The number of columns of the matrix A. n 0.

a

REAL for slascl

DOUBLE PRECISION for dlascl

COMPLEX for clascl

DOUBLE COMPLEX for zlascl

Array, size (lda, n). The matrix to be multiplied by cto/cfrom. See type for the storage type.

lda

INTEGER. The leading dimension of the array a.

lda max(1,m).

Output Parameters

a

The multiplied matrix A.

info

INTEGER.

If info = 0 - successful exit

If info = -i < 0, the i-th argument had an illegal value.

See Also