_lat2_(3) | Library Functions Manual | _lat2_(3) |

# NAME

_lat2_ - <em>lat2</em>: triangular matrix, convert double <=> single

# SYNOPSIS

## Functions

subroutine **dlat2s** (uplo, n, a, lda, sa, ldsa, info)

**DLAT2S** converts a double-precision triangular matrix to a
single-precision triangular matrix. subroutine **zlat2c** (uplo, n, a,
lda, sa, ldsa, info)

**ZLAT2C** converts a double complex triangular matrix to a complex
triangular matrix.

# Detailed Description

# Function Documentation

## subroutine dlat2s (character uplo, integer n, double precision, dimension( lda, * ) a, integer lda, real, dimension( ldsa, * ) sa, integer ldsa, integer info)

**DLAT2S** converts a double-precision triangular matrix to a
single-precision triangular matrix.

**Purpose:**

DLAT2S converts a DOUBLE PRECISION triangular matrix, SA, to a SINGLE PRECISION triangular matrix, A. RMAX is the overflow for the SINGLE PRECISION arithmetic DLAS2S checks that all the entries of A are between -RMAX and RMAX. If not the conversion is aborted and a flag is raised. This is an auxiliary routine so there is no argument checking.

**Parameters**

*UPLO*

UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular.

*N*

N is INTEGER The number of rows and columns of the matrix A. N >= 0.

*A*

A is DOUBLE PRECISION array, dimension (LDA,N) On entry, the N-by-N triangular coefficient matrix A.

*LDA*

LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).

*SA*

SA is REAL array, dimension (LDSA,N) Only the UPLO part of SA is referenced. On exit, if INFO=0, the N-by-N coefficient matrix SA; if INFO>0, the content of the UPLO part of SA is unspecified.

*LDSA*

LDSA is INTEGER The leading dimension of the array SA. LDSA >= max(1,M).

*INFO*

INFO is INTEGER = 0: successful exit. = 1: an entry of the matrix A is greater than the SINGLE PRECISION overflow threshold, in this case, the content of the UPLO part of SA in exit is unspecified.

**Author**

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **110** of file **dlat2s.f**.

## subroutine zlat2c (character uplo, integer n, complex*16, dimension( lda, * ) a, integer lda, complex, dimension( ldsa, * ) sa, integer ldsa, integer info)

**ZLAT2C** converts a double complex triangular matrix to a
complex triangular matrix.

**Purpose:**

ZLAT2C converts a COMPLEX*16 triangular matrix, SA, to a COMPLEX triangular matrix, A. RMAX is the overflow for the SINGLE PRECISION arithmetic ZLAT2C checks that all the entries of A are between -RMAX and RMAX. If not the conversion is aborted and a flag is raised. This is an auxiliary routine so there is no argument checking.

**Parameters**

*UPLO*

UPLO is CHARACTER*1 = 'U': A is upper triangular; = 'L': A is lower triangular.

*N*

N is INTEGER The number of rows and columns of the matrix A. N >= 0.

*A*

A is COMPLEX*16 array, dimension (LDA,N) On entry, the N-by-N triangular coefficient matrix A.

*LDA*

LDA is INTEGER The leading dimension of the array A. LDA >= max(1,N).

*SA*

SA is COMPLEX array, dimension (LDSA,N) Only the UPLO part of SA is referenced. On exit, if INFO=0, the N-by-N coefficient matrix SA; if INFO>0, the content of the UPLO part of SA is unspecified.

*LDSA*

LDSA is INTEGER The leading dimension of the array SA. LDSA >= max(1,M).

*INFO*

INFO is INTEGER = 0: successful exit. = 1: an entry of the matrix A is greater than the SINGLE PRECISION overflow threshold, in this case, the content of the UPLO part of SA in exit is unspecified.

**Author**

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **110** of file **zlat2c.f**.

# Author

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