1STRMV(1)                         BLAS routine                         STRMV(1)
2
3
4

NAME

6       STRMV - one of the matrix-vector operations   x := A*x, or x := A'*x,
7

SYNOPSIS

9       SUBROUTINE STRMV(UPLO,TRANS,DIAG,N,A,LDA,X,INCX)
10
11           INTEGER                                      INCX,LDA,N
12
13           CHARACTER                                    DIAG,TRANS,UPLO
14
15           REAL                                         A(LDA,*),X(*)
16

PURPOSE

18       STRMV  performs one of the matrix-vector operations
19
20       where  x  is an n element vector and  A is an n by n unit, or non-unit,
21       upper or lower triangular matrix.
22
23

ARGUMENTS

25       UPLO   - CHARACTER*1.
26              On entry, UPLO specifies whether the matrix is an upper or lower
27              triangular matrix as follows:
28
29              UPLO = 'U' or 'u'   A is an upper triangular matrix.
30
31              UPLO = 'L' or 'l'   A is a lower triangular matrix.
32
33              Unchanged on exit.
34
35       TRANS  - CHARACTER*1.
36              On  entry, TRANS specifies the operation to be performed as fol‐
37              lows:
38
39              TRANS = 'N' or 'n'   x := A*x.
40
41              TRANS = 'T' or 't'   x := A'*x.
42
43              TRANS = 'C' or 'c'   x := A'*x.
44
45              Unchanged on exit.
46
47       DIAG   - CHARACTER*1.
48              On entry, DIAG specifies whether or not A is unit triangular  as
49              follows:
50
51              DIAG = 'U' or 'u'   A is assumed to be unit triangular.
52
53              DIAG = 'N' or 'n'   A is not assumed to be unit triangular.
54
55              Unchanged on exit.
56
57       N      - INTEGER.
58              On  entry,  N specifies the order of the matrix A.  N must be at
59              least zero.  Unchanged on exit.
60
61       A      - REAL             array of DIMENSION ( LDA, n ).
62              Before entry with  UPLO = 'U' or 'u', the leading n by  n  upper
63              triangular part of the array A must contain the upper triangular
64              matrix and the strictly lower triangular part of A is not refer‐
65              enced.   Before entry with UPLO = 'L' or 'l', the leading n by n
66              lower triangular part of the array A must contain the lower tri‐
67              angular  matrix  and  the strictly upper triangular part of A is
68              not referenced.  Note that when  DIAG = 'U' or 'u', the diagonal
69              elements  of  A are not referenced either, but are assumed to be
70              unity.  Unchanged on exit.
71
72       LDA    - INTEGER.
73              On entry, LDA specifies the first dimension of A as declared  in
74              the  calling  (sub)  program.  LDA must be at least max( 1, n ).
75              Unchanged on exit.
76
77       X      - REAL             array of dimension at least
78              ( 1 + ( n - 1 )*abs( INCX ) ).  Before  entry,  the  incremented
79              array X must contain the n element vector x. On exit, X is over‐
80              written with the tranformed vector x.
81
82       INCX   - INTEGER.
83              On entry, INCX specifies the increment for the  elements  of  X.
84              INCX must not be zero.  Unchanged on exit.
85
86              Level 2 Blas routine.
87
88              --  Written on 22-October-1986.  Jack Dongarra, Argonne National
89              Lab.  Jeremy Du Croz, Nag Central Office.  Sven Hammarling,  Nag
90              Central Office.  Richard Hanson, Sandia National Labs.
91
92
93
94BLAS routine                     November 2006                        STRMV(1)