---
name: "dqrt12.f"
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/dqrt12.f"
---

# dqrt12.f(3)

## NAME

TESTING/LIN/dqrt12.f

## SYNOPSIS

### Functions/Subroutines

double precision function **dqrt12** (m, n, a, lda, s, work, lwork)\
 **DQRT12**

## Function/Subroutine Documentation

### double precision function dqrt12 (integer m, integer n, double precision, dimension( lda, \* ) a, integer lda, double precision, dimension( \* ) s, double precision, dimension( lwork ) work, integer lwork)

**DQRT12**

**Purpose:**

```
!>
!> DQRT12 computes the singular values `svlues' of the upper trapezoid
!> of A(1:M,1:N) and returns the ratio
!>
!>      || svlues - s ||/(||s||*eps*max(M,N))
!>
```

**Parameters**

*M*

```
!>          M is INTEGER
!>          The number of rows of the matrix A.
!>
```

*N*

```
!>          N is INTEGER
!>          The number of columns of the matrix A.
!>
```

*A*

```
!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The M-by-N matrix A. Only the upper trapezoid is referenced.
!>
```

*LDA*

```
!>          LDA is INTEGER
!>          The leading dimension of the array A.
!>
```

*S*

```
!>          S is DOUBLE PRECISION array, dimension (min(M,N))
!>          The singular values of the matrix A.
!>
```

*WORK*

```
!>          WORK is DOUBLE PRECISION array, dimension (LWORK)
!>
```

*LWORK*

```
!>          LWORK is INTEGER
!>          The length of the array WORK. LWORK >= max(M*N + 4*min(M,N) +
!>          max(M,N), M*N+2*MIN( M, N )+4*N).
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **88** of file **dqrt12.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.