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

NAME

6       CHEMV - the matrix-vector operation   y := alpha*A*x + beta*y,
7

SYNOPSIS

9       SUBROUTINE CHEMV(UPLO,N,ALPHA,A,LDA,X,INCX,BETA,Y,INCY)
10
11           COMPLEX                                             ALPHA,BETA
12
13           INTEGER                                             INCX,INCY,LDA,N
14
15           CHARACTER                                           UPLO
16
17           COMPLEX                                             A(LDA,*),X(*),Y(*)
18

PURPOSE

20       CHEMV  performs the matrix-vector  operation
21
22       where alpha and beta are scalars, x and y are n element vectors  and  A
23       is an n by n hermitian matrix.
24
25

ARGUMENTS

27       UPLO   - CHARACTER*1.
28              On  entry,  UPLO specifies whether the upper or lower triangular
29              part of the array A is to be referenced as follows:
30
31              UPLO = 'U' or 'u'   Only the upper triangular part of A is to be
32              referenced.
33
34              UPLO = 'L' or 'l'   Only the lower triangular part of A is to be
35              referenced.
36
37              Unchanged on exit.
38
39       N      - INTEGER.
40              On entry, N specifies the order of the matrix A.  N must  be  at
41              least zero.  Unchanged on exit.
42
43       ALPHA  - COMPLEX         .
44              On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.
45
46       A      - COMPLEX          array of DIMENSION ( LDA, n ).
47              Before  entry  with  UPLO = 'U' or 'u', the leading n by n upper
48              triangular part of the array A must contain the upper triangular
49              part  of  the hermitian matrix and the strictly lower triangular
50              part of A is not referenced.  Before entry with UPLO  =  'L'  or
51              'l',  the  leading  n  by n lower triangular part of the array A
52              must contain the lower triangular part of the  hermitian  matrix
53              and  the  strictly upper triangular part of A is not referenced.
54              Note that the imaginary parts of the diagonal elements need  not
55              be set and are assumed to be zero.  Unchanged on exit.
56
57       LDA    - INTEGER.
58              On  entry, LDA specifies the first dimension of A as declared in
59              the calling (sub) program. LDA must be at least  max(  1,  n  ).
60              Unchanged on exit.
61
62       X      - COMPLEX          array of dimension at least
63              (  1  +  ( n - 1 )*abs( INCX ) ).  Before entry, the incremented
64              array X must contain the n element vector x.  Unchanged on 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 + ( n - 1 )*abs( INCY ) ).  Before  entry,  the  incremented
76              array Y must contain the n element vector y. On exit, Y is over‐
77              written by the updated vector y.
78
79       INCY   - INTEGER.
80              On entry, INCY specifies the increment for the  elements  of  Y.
81              INCY must not be zero.  Unchanged on exit.
82
83              Level 2 Blas routine.
84
85              --  Written on 22-October-1986.  Jack Dongarra, Argonne National
86              Lab.  Jeremy Du Croz, Nag Central Office.  Sven Hammarling,  Nag
87              Central Office.  Richard Hanson, Sandia National Labs.
88
89
90
91BLAS routine                     November 2006                        CHEMV(1)