---
name: "dpot06.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/dpot06.f"
---

# dpot06.f(3)

## NAME

TESTING/LIN/dpot06.f

## SYNOPSIS

### Functions/Subroutines

subroutine **dpot06** (uplo, n, nrhs, a, lda, x, ldx, b, ldb, rwork, resid)\
 **DPOT06**

## Function/Subroutine Documentation

### subroutine dpot06 (character uplo, integer n, integer nrhs, double precision, dimension( lda, \* ) a, integer lda, double precision, dimension( ldx, \* ) x, integer ldx, double precision, dimension( ldb, \* ) b, integer ldb, double precision, dimension( \* ) rwork, double precision resid)

**DPOT06**

**Purpose:**

```
!>
!> DPOT06 computes the residual for a solution of a system of linear
!> equations  A*x = b :
!>    RESID = norm(B - A*X,inf) / ( norm(A,inf) * norm(X,inf) * 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.
!>
```

*NRHS*

```
!>          NRHS is INTEGER
!>          The number of columns of B, the matrix of right hand sides.
!>          NRHS >= 0.
!>
```

*A*

```
!>          A is DOUBLE PRECISION array, dimension (LDA,N)
!>          The original M x N matrix A.
!>
```

*LDA*

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

*X*

```
!>          X is DOUBLE PRECISION array, dimension (LDX,NRHS)
!>          The computed solution vectors for the system of linear
!>          equations.
!>
```

*LDX*

```
!>          LDX is INTEGER
!>          The leading dimension of the array X.  If TRANS = 'N',
!>          LDX >= max(1,N); if TRANS = 'T' or 'C', LDX >= max(1,N).
!>
```

*B*

```
!>          B is DOUBLE PRECISION array, dimension (LDB,NRHS)
!>          On entry, the right hand side vectors for the system of
!>          linear equations.
!>          On exit, B is overwritten with the difference B - A*X.
!>
```

*LDB*

```
!>          LDB is INTEGER
!>          The leading dimension of the array B.  IF TRANS = 'N',
!>          LDB >= max(1,M); if TRANS = 'T' or 'C', LDB >= max(1,N).
!>
```

*RWORK*

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

*RESID*

```
!>          RESID is DOUBLE PRECISION
!>          The maximum over the number of right hand sides of
!>          norm(B - A*X) / ( norm(A) * norm(X) * EPS ).
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **125** of file **dpot06.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.