[ Previous |
Next |
Contents |
Glossary |
Home |
Search ]

*AIX Version 4.3 Base Operating System and Extensions Technical Reference, Volume 2*

## STRMV, DTRMV, CTRMV, or ZTRMV Subroutine

### Purpose

Performs matrix-vector operations using a triangular matrix.

### Library

BLAS Library (**libblas.a**)

### FORTRAN Syntax

**SUBROUTINE STRMV(***UPLO***, ***TRANS***, ***DIAG***, ***N***,**
*A***, ***LDA***, ***X***, ***INCX***)**
**INTEGER** *INCX***,***LDA***,***N*
**CHARACTER*1** *DIAG***,***TRANS***,***UPLO*
**REAL** *A***(***LDA***,*), ***X***(*)**

**SUBROUTINE DTRMV(***UPLO***, ***TRANS***, ***DIAG***, ***N***,**
*A***, ***LDA***, ***X***, ***INCX***)**
**INTEGER** *INCX***,***LDA***,***N*
**CHARACTER*1** *DIAG***,***TRANS***,***UPLO*
**DOUBLE PRECISION** *A***(***LDA***,*), ***X***(*)**

**SUBROUTINE CTRMV(***UPLO***, ***TRANS***, ***DIAG***, ***N***,**
*A***, ***LDA***, ***X***, ***INCX***)**
**INTEGER** *INCX***,***LDA***,***N*
**CHARACTER*1** *DIAG***,***TRANS***,***UPLO*
**COMPLEX** *A***(***LDA***,*), ***X***(*)**

**SUBROUTINE ZTRMV(***UPLO***, ***TRANS***, ***DIAG***, ***N***,**
*A***, ***LDA***, ***X***, ***INCX***)**
**INTEGER** *INCX***,***LDA***,***N*
**CHARACTER*1** *DIAG***,***TRANS***,***UPLO*
**COMPLEX*16** *A***(***LDA***,*),***X***(*)**

### Description

The **STRMV**, **DTRMV**, **CTRMV**, or **ZTRMV** subroutine performs one of the matrix-vector operations:

`x := ``A`` * x`

OR

`x := ``A``' * x`

where x is an *N* element vector and *A* is an *N* by *N* unit, or non-unit, upper or lower triangular matrix.

### Parameters

*UPLO* |
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. |
Unchanged on exit. |

*TRANS* |
On entry, *TRANS* specifies the operation to be performed as follows:
*TRANS* = 'N' or 'n' |
x := *A ** x |
*TRANS* = 'T' or 't' |
x := *A*' * x |
*TRANS* = 'C' or 'c' |
x := *A*' * x |
Unchanged on exit. |

*DIAG* |
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. |
Unchanged on exit. |

*N* |
On entry, *N* specifies the order of the matrix *A*; *N* must be at least 0; unchanged on exit. |

*A* |
An array of dimension (* LDA*, *N* ); on 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; on 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. When *DIAG* = 'U' or 'u', the diagonal elements of* A *are not referenced, but are assumed to be unity; unchanged on exit. |

*LDA* |
On entry, *LDA* specifies the first dimension of *A *as declared in the calling (sub) program. *LDA *must be at least max( 1, *N* ); unchanged on exit. |

*X* |
A vector of dimension at least (1 + (*N*-1) * abs( *INCX* ) ). On entry, the incremented array *X* must contain the *N* element vector x; on exit, *X* is overwritten with the transformed vector x. |

*INCX* |
On entry, *INCX *specifies the increment for the elements of *X*; *INCX* must not be 0; unchanged on exit. |

[ Previous |
Next |
Contents |
Glossary |
Home |
Search ]