---
name: "sqrt15.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/sqrt15.f"
---

# sqrt15.f(3)

## NAME

TESTING/LIN/sqrt15.f

## SYNOPSIS

### Functions/Subroutines

subroutine **sqrt15** (scale, rksel, m, n, nrhs, a, lda, b, ldb, s, rank, norma, normb, iseed, work, lwork)\
 **SQRT15**

## Function/Subroutine Documentation

### subroutine sqrt15 (integer scale, integer rksel, integer m, integer n, integer nrhs, real, dimension( lda, \* ) a, integer lda, real, dimension( ldb, \* ) b, integer ldb, real, dimension( \* ) s, integer rank, real norma, real normb, integer, dimension( 4 ) iseed, real, dimension( lwork ) work, integer lwork)

**SQRT15**

**Purpose:**

```
!>
!> SQRT15 generates a matrix with full or deficient rank and of various
!> norms.
!>
```

**Parameters**

*SCALE*

```
!>          SCALE is INTEGER
!>          SCALE = 1: normally scaled matrix
!>          SCALE = 2: matrix scaled up
!>          SCALE = 3: matrix scaled down
!>
```

*RKSEL*

```
!>          RKSEL is INTEGER
!>          RKSEL = 1: full rank matrix
!>          RKSEL = 2: rank-deficient matrix
!>
```

*M*

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

*N*

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

*NRHS*

```
!>          NRHS is INTEGER
!>          The number of columns of B.
!>
```

*A*

```
!>          A is REAL array, dimension (LDA,N)
!>          The M-by-N matrix A.
!>
```

*LDA*

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

*B*

```
!>          B is REAL array, dimension (LDB, NRHS)
!>          A matrix that is in the range space of matrix A.
!>
```

*LDB*

```
!>          LDB is INTEGER
!>          The leading dimension of the array B.
!>
```

*S*

```
!>          S is REAL array, dimension MIN(M,N)
!>          Singular values of A.
!>
```

*RANK*

```
!>          RANK is INTEGER
!>          number of nonzero singular values of A.
!>
```

*NORMA*

```
!>          NORMA is REAL
!>          one-norm of A.
!>
```

*NORMB*

```
!>          NORMB is REAL
!>          one-norm of B.
!>
```

*ISEED*

```
!>          ISEED is integer array, dimension (4)
!>          seed for random number generator.
!>
```

*WORK*

```
!>          WORK is REAL array, dimension (LWORK)
!>
```

*LWORK*

```
!>          LWORK is INTEGER
!>          length of work space required.
!>          LWORK >= MAX(M+MIN(M,N),NRHS*MIN(M,N),2*N+M)
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **146** of file **sqrt15.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.