---
name: "dppt03.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/dppt03.f"
---

# dppt03.f(3)

## NAME

TESTING/LIN/dppt03.f

## SYNOPSIS

### Functions/Subroutines

subroutine **dppt03** (uplo, n, a, ainv, work, ldwork, rwork, rcond, resid)\
 **DPPT03**

## Function/Subroutine Documentation

### subroutine dppt03 (character uplo, integer n, double precision, dimension( \* ) a, double precision, dimension( \* ) ainv, double precision, dimension( ldwork, \* ) work, integer ldwork, double precision, dimension( \* ) rwork, double precision rcond, double precision resid)

**DPPT03**

**Purpose:**

```
!>
!> DPPT03 computes the residual for a symmetric packed 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 DOUBLE PRECISION array, dimension (N*(N+1)/2)
!>          The original symmetric matrix A, stored as a packed
!>          triangular matrix.
!>
```

*AINV*

```
!>          AINV is DOUBLE PRECISION array, dimension (N*(N+1)/2)
!>          The (symmetric) inverse of the matrix A, stored as a packed
!>          triangular matrix.
!>
```

*WORK*

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

*LDWORK*

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

*RWORK*

```
!>          RWORK is DOUBLE PRECISION array, dimension (N)
!>
```

*RCOND*

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

*RESID*

```
!>          RESID is DOUBLE PRECISION
!>          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 **108** of file **dppt03.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.