---
name: "drzt02.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/drzt02.f"
---

# drzt02.f(3)

## NAME

TESTING/LIN/drzt02.f

## SYNOPSIS

### Functions/Subroutines

double precision function **drzt02** (m, n, af, lda, tau, work, lwork)\
 **DRZT02**

## Function/Subroutine Documentation

### double precision function drzt02 (integer m, integer n, double precision, dimension( lda, \* ) af, integer lda, double precision, dimension( \* ) tau, double precision, dimension( lwork ) work, integer lwork)

**DRZT02**

**Purpose:**

```
!>
!> DRZT02 returns
!>      || I - Q'*Q || / ( M * eps)
!> where the matrix Q is defined by the Householder transformations
!> generated by DTZRZF.
!>
```

**Parameters**

*M*

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

*N*

```
!>          N is INTEGER
!>          The number of columns of the matrix AF.
!>
```

*AF*

```
!>          AF is DOUBLE PRECISION array, dimension (LDA,N)
!>          The output of DTZRZF.
!>
```

*LDA*

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

*TAU*

```
!>          TAU is DOUBLE PRECISION array, dimension (M)
!>          Details of the Householder transformations as returned by
!>          DTZRZF.
!>
```

*WORK*

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

*LWORK*

```
!>          LWORK is INTEGER
!>          length of WORK array. LWORK >= N*N+N*NB.
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **89** of file **drzt02.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.