# spst01.f - Man Page

TESTING/LIN/spst01.f

## Synopsis

### Functions/Subroutines

subroutine spst01 (uplo, n, a, lda, afac, ldafac, perm, ldperm, piv, rwork, resid, rank)
SPST01

## Function/Subroutine Documentation

### subroutine spst01 (character uplo, integer n, real, dimension( lda, * ) a, integer lda, real, dimension( ldafac, * ) afac, integer ldafac, real, dimension( ldperm, * ) perm, integer ldperm, integer, dimension( * ) piv, real, dimension( * ) rwork, real resid, integer rank)

SPST01

Purpose:

``` SPST01 reconstructs a symmetric positive semidefinite matrix A
from its L or U factors and the permutation matrix P and computes
the residual
norm( P*L*L'*P' - A ) / ( N * norm(A) * EPS ) or
norm( P*U'*U*P' - A ) / ( N * norm(A) * EPS ),
where EPS is the machine epsilon.```
Parameters

UPLO

```          UPLO is CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric matrix A is stored:
= 'U':  Upper triangular
= 'L':  Lower triangular```

N

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

A

```          A is REAL array, dimension (LDA,N)
The original symmetric matrix A.```

LDA

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

AFAC

```          AFAC is REAL array, dimension (LDAFAC,N)
The factor L or U from the L*L' or U'*U
factorization of A.```

LDAFAC

```          LDAFAC is INTEGER
The leading dimension of the array AFAC.  LDAFAC >= max(1,N).```

PERM

```          PERM is REAL array, dimension (LDPERM,N)
Overwritten with the reconstructed matrix, and then with the
difference P*L*L'*P' - A (or P*U'*U*P' - A)```

LDPERM

```          LDPERM is INTEGER
The leading dimension of the array PERM.
LDAPERM >= max(1,N).```

PIV

```          PIV is INTEGER array, dimension (N)
PIV is such that the nonzero entries are
P( PIV( K ), K ) = 1.```

RWORK

`          RWORK is REAL array, dimension (N)`

RESID

```          RESID is REAL
If UPLO = 'L', norm(L*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U'*U - A) / ( N * norm(A) * EPS )```

RANK

```          RANK is INTEGER
number of nonzero singular values of A.```
Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 132 of file spst01.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page spst01(3) is an alias of spst01.f(3).

Tue Nov 28 2023 12:08:43 Version 3.12.0 LAPACK