NAME

ctpmv - perform one of the matrix-vector operations   x := A∗x, or x := A’∗x, or x := conjg( A’ )∗x

SYNOPSIS

SUBROUTINE CTPMV ( UPLO, TRANS, DIAG, N, AP, X, INCX )

INTEGER INCX, N

CHARACTER∗1 DIAG, TRANS, UPLO

COMPLEX AP( ∗ ), X( ∗ )

#include <sunperf.h>

void ctpmv(char uplo, char trans, char diag, int n, complex ∗cap, complex ∗cx, int incx) ;

PURPOSE

CTPMV  performs one of the matrix-vector operations x := A∗x, or x := A’∗x, or x := conjg( 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, supplied in packed form. 
 

PARAMETERS

UPLO - 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.
 
Unchanged on exit.

TRANS - CHARACTER∗1. 
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 := conjg( A’ )∗x.
 
Unchanged on exit.

DIAG - 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.
 
Unchanged on exit.

N - INTEGER. 
On entry, N specifies the order of the matrix A. N must be at least zero. Unchanged on exit.

AP - COMPLEX          array of DIMENSION at least
( ( n∗( n + 1 ) )/2 ). Before entry with  UPLO = ’U’ or ’u’, the array AP must contain the upper triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 1, 2 ) and a( 2, 2 ) respectively, and so on. Before entry with UPLO = ’L’ or ’l’, the array AP must contain the lower triangular matrix packed sequentially, column by column, so that AP( 1 ) contains a( 1, 1 ), AP( 2 ) and AP( 3 ) contain a( 2, 1 ) and a( 3, 1 ) respectively, and so on. Note that when  DIAG = ’U’ or ’u’, the diagonal elements of A are not referenced, but are assumed to be unity. Unchanged on exit.

X - COMPLEX          array of dimension at least
( 1 + ( n - 1 )∗abs( INCX ) ). Before entry, the incremented array X must contain the n element vector x. On exit, X is overwritten with the tranformed vector x.

INCX - INTEGER. 
On entry, INCX specifies the increment for the elements of X. INCX must not be zero. Unchanged on exit.

SunOS 5.0  —  Last change: 10 Dec 1998