Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 3/31/2025
Public

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dlat2s

Converts a double-precision triangular matrix to a single-precision triangular matrix.

Syntax

call dlat2s( uplo, n, a, lda, sa, ldsa, info )

Include Files

  • mkl.fi

Description

This routine converts a double-precision triangular matrix A to a single-precision triangular matrix SA. dlat2s checks that all the elements of A are between -RMAX and RMAX, where RMAX is the overflow for the single-precision arithmetic. If this condition is not met, the conversion is aborted and a flag is raised. The routine does no parameter checking.

Input Parameters

uplo

CHARACTER*1.

Specifies whether the matrix A is upper or lower triangular:

= 'U': A is upper triangular,

= 'L': A is lower triangular.

n

INTEGER. The number of rows and columns of the matrix A. n≥ 0.

a

DOUBLE PRECISION.

Array, DIMENSION (lda, *).

On entry, the n-by-n triangular matrix A.

lda

INTEGER. The leading dimension of the array a. lda ≥ max(1,n).

ldsa

INTEGER. The leading dimension of the array sa. ldsa ≥ max(1,n).

Output Parameters

sa

REAL.

Array, DIMENSION (ldsa, *).

Only the part of sa determined by uplo is referenced. On exit,

  • if info = 0, the n-by-n triangular matrix SA,

  • if info > 0, the content of the part of sa determined by uplo is unspecified.

info

INTEGER.

=0: successful exit,

> 0: an element of the matrix A is greater than the single-precision overflow threshold; in this case, the content of the part of sa determined by uplo is unspecified on exit.