---
name: "spot03.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/spot03.f"
---

# spot03.f(3)

## NAME

TESTING/LIN/spot03.f

## SYNOPSIS

### Functions/Subroutines

subroutine **spot03** (uplo, n, a, lda, ainv, ldainv, work, ldwork, rwork, rcond, resid)\
 **SPOT03**

## Function/Subroutine Documentation

### subroutine spot03 (character uplo, integer n, real, dimension( lda, \* ) a, integer lda, real, dimension( ldainv, \* ) ainv, integer ldainv, real, dimension( ldwork, \* ) work, integer ldwork, real, dimension( \* ) rwork, real rcond, real resid)

**SPOT03**

**Purpose:**

```
!>
!> SPOT03 computes the residual for a symmetric matrix times its
!> inverse:
!>    norm( I - A*AINV ) / ( N * norm(A) * norm(AINV) * 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)
!>
```

*AINV*

```
!>          AINV is REAL array, dimension (LDAINV,N)
!>          On entry, the inverse of the matrix A, stored as a symmetric
!>          matrix in the same format as A.
!>          In this version, AINV is expanded into a full matrix and
!>          multiplied by A, so the opposing triangle of AINV will be
!>          changed; i.e., if the upper triangular part of AINV is
!>          stored, the lower triangular part will be used as work space.
!>
```

*LDAINV*

```
!>          LDAINV is INTEGER
!>          The leading dimension of the array AINV.  LDAINV >= max(1,N).
!>
```

*WORK*

```
!>          WORK is REAL array, dimension (LDWORK,N)
!>
```

*LDWORK*

```
!>          LDWORK is INTEGER
!>          The leading dimension of the array WORK.  LDWORK >= max(1,N).
!>
```

*RWORK*

```
!>          RWORK is REAL array, dimension (N)
!>
```

*RCOND*

```
!>          RCOND is REAL
!>          The reciprocal of the condition number of A, computed as
!>          ( 1/norm(A) ) / norm(AINV).
!>
```

*RESID*

```
!>          RESID is REAL
!>          norm(I - A*AINV) / ( N * norm(A) * norm(AINV) * EPS )
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **123** of file **spot03.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.