---
name: "ztrt06.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/ztrt06.f"
---

# ztrt06.f(3)

## NAME

TESTING/LIN/ztrt06.f

## SYNOPSIS

### Functions/Subroutines

subroutine **ztrt06** (rcond, rcondc, uplo, diag, n, a, lda, rwork, rat)\
 **ZTRT06**

## Function/Subroutine Documentation

### subroutine ztrt06 (double precision rcond, double precision rcondc, character uplo, character diag, integer n, complex\*16, dimension( lda, \* ) a, integer lda, double precision, dimension( \* ) rwork, double precision rat)

**ZTRT06**

**Purpose:**

```
!>
!> ZTRT06 computes a test ratio comparing RCOND (the reciprocal
!> condition number of a triangular matrix A) and RCONDC, the estimate
!> computed by ZTRCON.  Information about the triangular matrix A is
!> used if one estimate is zero and the other is non-zero to decide if
!> underflow in the estimate is justified.
!>
```

**Parameters**

*RCOND*

```
!>          RCOND is DOUBLE PRECISION
!>          The estimate of the reciprocal condition number obtained by
!>          forming the explicit inverse of the matrix A and computing
!>          RCOND = 1/( norm(A) * norm(inv(A)) ).
!>
```

*RCONDC*

```
!>          RCONDC is DOUBLE PRECISION
!>          The estimate of the reciprocal condition number computed by
!>          ZTRCON.
!>
```

*UPLO*

```
!>          UPLO is CHARACTER
!>          Specifies whether the matrix A is upper or lower triangular.
!>          = 'U':  Upper triangular
!>          = 'L':  Lower triangular
!>
```

*DIAG*

```
!>          DIAG is CHARACTER
!>          Specifies whether or not the matrix A is unit triangular.
!>          = 'N':  Non-unit triangular
!>          = 'U':  Unit triangular
!>
```

*N*

```
!>          N is INTEGER
!>          The order of the matrix A.  N >= 0.
!>
```

*A*

```
!>          A is COMPLEX*16 array, dimension (LDA,N)
!>          The triangular matrix A.  If UPLO = 'U', the leading n by n
!>          upper triangular part of the array A contains the upper
!>          triangular matrix, and the strictly lower triangular part of
!>          A is not referenced.  If UPLO = 'L', the leading n by n lower
!>          triangular part of the array A contains the lower triangular
!>          matrix, and the strictly upper triangular part of A is not
!>          referenced.  If DIAG = 'U', the diagonal elements of A are
!>          also not referenced and are assumed to be 1.
!>
```

*LDA*

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

*RWORK*

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

*RAT*

```
!>          RAT is DOUBLE PRECISION
!>          The test ratio.  If both RCOND and RCONDC are nonzero,
!>             RAT = MAX( RCOND, RCONDC )/MIN( RCOND, RCONDC ) - 1.
!>          If RAT = 0, the two estimates are exactly the same.
!>
```

**Author**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line **120** of file **ztrt06.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.