---
name: "_lag2_"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/_lag2_"
---
# \_lag2\_(3)
\lag2\: general matrix, convert double \<=\> single
## NAME
\_lag2\_ - \lag2\: general matrix, convert double \<=\> single
## SYNOPSIS
### Functions
subroutine **clag2z** (m, n, sa, ldsa, a, lda, info)\
**CLAG2Z** converts a complex single precision matrix to a complex double precision matrix. subroutine **dlag2s** (m, n, a, lda, sa, ldsa, info)\
**DLAG2S** converts a double precision matrix to a single precision matrix. subroutine **slag2d** (m, n, sa, ldsa, a, lda, info)\
**SLAG2D** converts a single precision matrix to a double precision matrix. subroutine **zlag2c** (m, n, a, lda, sa, ldsa, info)\
**ZLAG2C** converts a complex double precision matrix to a complex single precision matrix.
## Detailed Description
## Function Documentation
### subroutine clag2z (integer m, integer n, complex, dimension( ldsa, \* ) sa, integer ldsa, complex\*16, dimension( lda, \* ) a, integer lda, integer info)
**CLAG2Z** converts a complex single precision matrix to a complex double precision matrix.
**Purpose:**
```
!>
!> CLAG2Z converts a COMPLEX matrix, SA, to a COMPLEX*16 matrix, A.
!>
!> Note that while it is possible to overflow while converting
!> from double to single, it is not possible to overflow when
!> converting from single to double.
!>
!> This is an auxiliary routine so there is no argument checking.
!>
```
**Parameters**
*M*
```
!> M is INTEGER
!> The number of lines of the matrix A. M >= 0.
!>
```
*N*
```
!> N is INTEGER
!> The number of columns of the matrix A. N >= 0.
!>
```
*SA*
```
!> SA is COMPLEX array, dimension (LDSA,N)
!> On entry, the M-by-N coefficient matrix SA.
!>
```
*LDSA*
```
!> LDSA is INTEGER
!> The leading dimension of the array SA. LDSA >= max(1,M).
!>
```
*A*
```
!> A is COMPLEX*16 array, dimension (LDA,N)
!> On exit, the M-by-N coefficient matrix A.
!>
```
*LDA*
```
!> LDA is INTEGER
!> The leading dimension of the array A. LDA >= max(1,M).
!>
```
*INFO*
```
!> INFO is INTEGER
!> = 0: successful exit
!>
```
**Author**
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line **102** of file **clag2z.f**.
### subroutine dlag2s (integer m, integer n, double precision, dimension( lda, \* ) a, integer lda, real, dimension( ldsa, \* ) sa, integer ldsa, integer info)
**DLAG2S** converts a double precision matrix to a single precision matrix.
**Purpose:**
```
!>
!> DLAG2S converts a DOUBLE PRECISION matrix, A, to a SINGLE
!> PRECISION matrix, SA.
!>
!> RMAX is the overflow for the SINGLE PRECISION arithmetic
!> DLAG2S 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**
*M*
```
!> M is INTEGER
!> The number of lines of the matrix A. M >= 0.
!>
```
*N*
```
!> N is INTEGER
!> The number of columns of the matrix A. N >= 0.
!>
```
*A*
```
!> A is DOUBLE PRECISION array, dimension (LDA,N)
!> On entry, the M-by-N coefficient matrix A.
!>
```
*LDA*
```
!> LDA is INTEGER
!> The leading dimension of the array A. LDA >= max(1,M).
!>
```
*SA*
```
!> SA is REAL array, dimension (LDSA,N)
!> On exit, if INFO=0, the M-by-N coefficient matrix SA; if
!> INFO>0, the content 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 SA in exit is unspecified.
!>
```
**Author**
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line **107** of file **dlag2s.f**.
### subroutine slag2d (integer m, integer n, real, dimension( ldsa, \* ) sa, integer ldsa, double precision, dimension( lda, \* ) a, integer lda, integer info)
**SLAG2D** converts a single precision matrix to a double precision matrix.
**Purpose:**
```
!>
!> SLAG2D converts a SINGLE PRECISION matrix, SA, to a DOUBLE
!> PRECISION matrix, A.
!>
!> Note that while it is possible to overflow while converting
!> from double to single, it is not possible to overflow when
!> converting from single to double.
!>
!> This is an auxiliary routine so there is no argument checking.
!>
```
**Parameters**
*M*
```
!> M is INTEGER
!> The number of lines of the matrix A. M >= 0.
!>
```
*N*
```
!> N is INTEGER
!> The number of columns of the matrix A. N >= 0.
!>
```
*SA*
```
!> SA is REAL array, dimension (LDSA,N)
!> On entry, the M-by-N coefficient matrix SA.
!>
```
*LDSA*
```
!> LDSA is INTEGER
!> The leading dimension of the array SA. LDSA >= max(1,M).
!>
```
*A*
```
!> A is DOUBLE PRECISION array, dimension (LDA,N)
!> On exit, the M-by-N coefficient matrix A.
!>
```
*LDA*
```
!> LDA is INTEGER
!> The leading dimension of the array A. LDA >= max(1,M).
!>
```
*INFO*
```
!> INFO is INTEGER
!> = 0: successful exit
!>
```
**Author**
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line **103** of file **slag2d.f**.
### subroutine zlag2c (integer m, integer n, complex\*16, dimension( lda, \* ) a, integer lda, complex, dimension( ldsa, \* ) sa, integer ldsa, integer info)
**ZLAG2C** converts a complex double precision matrix to a complex single precision matrix.
**Purpose:**
```
!>
!> ZLAG2C converts a COMPLEX*16 matrix, SA, to a COMPLEX matrix, A.
!>
!> RMAX is the overflow for the SINGLE PRECISION arithmetic
!> ZLAG2C 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**
*M*
```
!> M is INTEGER
!> The number of lines of the matrix A. M >= 0.
!>
```
*N*
```
!> N is INTEGER
!> The number of columns of the matrix A. N >= 0.
!>
```
*A*
```
!> A is COMPLEX*16 array, dimension (LDA,N)
!> On entry, the M-by-N coefficient matrix A.
!>
```
*LDA*
```
!> LDA is INTEGER
!> The leading dimension of the array A. LDA >= max(1,M).
!>
```
*SA*
```
!> SA is COMPLEX array, dimension (LDSA,N)
!> On exit, if INFO=0, the M-by-N coefficient matrix SA; if
!> INFO>0, the content 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 SA in exit is unspecified.
!>
```
**Author**
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line **106** of file **zlag2c.f**.
## Author
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