# ztrsv.f man page

ztrsv.f ā

## Synopsis

### Functions/Subroutines

subroutine ztrsv (UPLO, TRANS, DIAG, N, A, LDA, X, INCX)
ZTRSV

## Function/Subroutine Documentation

### subroutine ztrsv (character UPLO, character TRANS, character DIAG, integer N, complex*16, dimension(lda,*) A, integer LDA, complex*16, dimension(*) X, integer INCX)

ZTRSV

Purpose:

``` ZTRSV  solves one of the systems of equations

A*x = b,   or   A**T*x = b,   or   A**H*x = b,

where b and x are n element vectors and A is an n by n unit, or
non-unit, upper or lower triangular matrix.

No test for singularity or near-singularity is included in this
routine. Such tests must be performed before calling this routine.```
Parameters:

UPLO

```          UPLO is CHARACTER*1
On entry, UPLO specifies whether the matrix is an upper or
lower triangular matrix as follows:

UPLO = 'U' or 'u'   A is an upper triangular matrix.

UPLO = 'L' or 'l'   A is a lower triangular matrix.```

TRANS

```          TRANS is CHARACTER*1
On entry, TRANS specifies the equations to be solved as
follows:

TRANS = 'N' or 'n'   A*x = b.

TRANS = 'T' or 't'   A**T*x = b.

TRANS = 'C' or 'c'   A**H*x = b.```

DIAG

```          DIAG is CHARACTER*1
On entry, DIAG specifies whether or not A is unit
triangular as follows:

DIAG = 'U' or 'u'   A is assumed to be unit triangular.

DIAG = 'N' or 'n'   A is not assumed to be unit
triangular.```

N

```          N is INTEGER
On entry, N specifies the order of the matrix A.
N must be at least zero.```

A

```          A is COMPLEX*16 array, dimension ( LDA, N )
Before entry with  UPLO = 'U' or 'u', the leading n by n
upper triangular part of the array A must contain the upper
triangular matrix and the strictly lower triangular part of
A is not referenced.
Before entry with UPLO = 'L' or 'l', the leading n by n
lower triangular part of the array A must contain the lower
triangular matrix and the strictly upper triangular part of
A is not referenced.
Note that when  DIAG = 'U' or 'u', the diagonal elements of
A are not referenced either, but are assumed to be unity.```

LDA

```          LDA is INTEGER
On entry, LDA specifies the first dimension of A as declared
in the calling (sub) program. LDA must be at least
max( 1, n ).```

X

```          X is COMPLEX*16 array, dimension at least
( 1 + ( n - 1 )*abs( INCX ) ).
Before entry, the incremented array X must contain the n
element right-hand side vector b. On exit, X is overwritten
with the solution vector x.```

INCX

```          INCX is INTEGER
On entry, INCX specifies the increment for the elements of
X. INCX must not be zero.```
Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

December 2016

Further Details:

```  Level 2 Blas routine.

-- Written on 22-October-1986.
Jack Dongarra, Argonne National Lab.
Jeremy Du Croz, Nag Central Office.
Sven Hammarling, Nag Central Office.
Richard Hanson, Sandia National Labs.```

Definition at line 151 of file ztrsv.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page ztrsv(3) is an alias of ztrsv.f(3).

Sat Jun 24 2017 Version 3.7.1 LAPACK