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

NAME

6       CGEMV  - one of the matrix-vector operations   y := alpha*A*x + beta*y,
7       or y := alpha*A'*x + beta*y, or   y := alpha*conjg( A' )*x + beta*y,
8

SYNOPSIS

10       SUBROUTINE CGEMV(TRANS,M,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
11
12           COMPLEX                                                ALPHA,BETA
13
14           INTEGER                                                INCX,INCY,LDA,M,N
15
16           CHARACTER                                              TRANS
17
18           COMPLEX                                                A(LDA,*),X(*),Y(*)
19

PURPOSE

21       CGEMV performs one of the matrix-vector operations
22
23       where alpha and beta are scalars, x and y are vectors and A is an m  by
24       n matrix.
25
26

ARGUMENTS

28       TRANS  - CHARACTER*1.
29              On  entry, TRANS specifies the operation to be performed as fol‐
30              lows:
31
32              TRANS = 'N' or 'n'   y := alpha*A*x + beta*y.
33
34              TRANS = 'T' or 't'   y := alpha*A'*x + beta*y.
35
36              TRANS = 'C' or 'c'   y := alpha*conjg( A' )*x + beta*y.
37
38              Unchanged on exit.
39
40       M      - INTEGER.
41              On entry, M specifies the number of rows of  the  matrix  A.   M
42              must be at least zero.  Unchanged on exit.
43
44       N      - INTEGER.
45              On  entry, N specifies the number of columns of the matrix A.  N
46              must be at least zero.  Unchanged on exit.
47
48       ALPHA  - COMPLEX         .
49              On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.
50
51       A      - COMPLEX          array of DIMENSION ( LDA, n ).
52              Before entry, the leading m by n part of the array A  must  con‐
53              tain the matrix of coefficients.  Unchanged on exit.
54
55       LDA    - INTEGER.
56              On  entry, LDA specifies the first dimension of A as declared in
57              the calling (sub) program. LDA must be at least  max(  1,  m  ).
58              Unchanged on exit.
59
60       X      - COMPLEX          array of DIMENSION at least
61              (  1  +  (  n - 1 )*abs( INCX ) ) when TRANS = 'N' or 'n' and at
62              least ( 1 + ( m - 1 )*abs( INCX ) )  otherwise.   Before  entry,
63              the incremented array X must contain the vector x.  Unchanged on
64              exit.
65
66       INCX   - INTEGER.
67              On entry, INCX specifies the increment for the  elements  of  X.
68              INCX must not be zero.  Unchanged on exit.
69
70       BETA   - COMPLEX         .
71              On  entry, BETA specifies the scalar beta. When BETA is supplied
72              as zero then Y need not be set on input.  Unchanged on exit.
73
74       Y      - COMPLEX          array of DIMENSION at least
75              ( 1 + ( m - 1 )*abs( INCY ) ) when TRANS = 'N'  or  'n'  and  at
76              least  (  1  +  ( n - 1 )*abs( INCY ) ) otherwise.  Before entry
77              with BETA non-zero, the incremented array  Y  must  contain  the
78              vector y. On exit, Y is overwritten by the updated vector y.
79
80       INCY   - INTEGER.
81              On  entry,  INCY  specifies the increment for the elements of Y.
82              INCY must not be zero.  Unchanged on exit.
83
84              Level 2 Blas routine.
85
86              -- Written on 22-October-1986.  Jack Dongarra, Argonne  National
87              Lab.   Jeremy Du Croz, Nag Central Office.  Sven Hammarling, Nag
88              Central Office.  Richard Hanson, Sandia National Labs.
89
90
91
92BLAS routine                     November 2006                        CGEMV(1)