ssymm(l)

1SSYMM(1)                         BLAS routine                         SSYMM(1)
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NAME

6       SSYMM - one of the matrix-matrix operations   C := alpha*A*B + beta*C,
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SYNOPSIS

9       SUBROUTINE SSYMM(SIDE,UPLO,M,N,ALPHA,A,LDA,B,LDB,BETA,C,LDC)
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11           REAL                                                     ALPHA,BETA
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13           INTEGER                                                  LDA,LDB,LDC,M,N
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15           CHARACTER                                                SIDE,UPLO
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17           REAL                                                     A(LDA,*),B(LDB,*),C(LDC,*)
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PURPOSE

20       SSYMM  performs one of the matrix-matrix operations
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22       or
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24          C := alpha*B*A + beta*C,
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26       where alpha and beta are scalars,  A is a symmetric matrix and  B and C
27       are  m by n matrices.
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ARGUMENTS

31       SIDE   - CHARACTER*1.
32              On entry,  SIDE  specifies whether   the   symmetric  matrix   A
33              appears on the  left or right  in the  operation as follows:
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35              SIDE = 'L' or 'l'   C := alpha*A*B + beta*C,
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37              SIDE = 'R' or 'r'   C := alpha*B*A + beta*C,
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39              Unchanged on exit.
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41       UPLO   - CHARACTER*1.
42              On   entry,    UPLO   specifies   whether  the  upper  or  lower
43              triangular  part  of  the  symmetric  matrix    A   is   to   be
44              referenced as follows:
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46              UPLO  =  'U' or 'u'   Only the upper triangular part of the sym‐
47              metric matrix is to be referenced.
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49              UPLO = 'L' or 'l'   Only the lower triangular part of  the  sym‐
50              metric matrix is to be referenced.
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52              Unchanged on exit.
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54       M      - INTEGER.
55              On  entry,  M  specifies the number of rows of the matrix  C.  M
56              must be at least zero.  Unchanged on exit.
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58       N      - INTEGER.
59              On entry, N specifies the number of columns of the matrix C.   N
60              must be at least zero.  Unchanged on exit.
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62       ALPHA  - REAL            .
63              On entry, ALPHA specifies the scalar alpha.  Unchanged on exit.
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65       A      - REAL             array of DIMENSION ( LDA, ka ), where ka is
66              m   when   SIDE = 'L' or 'l'  and is  n otherwise.  Before entry
67              with  SIDE = 'L' or 'l',  the  m by m   part  of  the  array   A
68              must  contain the  symmetric matrix,  such that when  UPLO = 'U'
69              or 'u', the leading m by m upper triangular part of the array  A
70              must  contain the upper triangular part of the  symmetric matrix
71              and the  strictly  lower triangular part of  A   is  not  refer‐
72              enced,   and when  UPLO = 'L' or 'l', the leading  m by m  lower
73              triangular part  of the  array  A must  contain  the  lower tri‐
74              angular  part   of the  symmetric matrix and the  strictly upper
75              triangular part of  A  is not referenced.   Before  entry   with
76              SIDE = 'R' or 'r',  the  n by n  part of the array  A  must con‐
77              tain the  symmetric matrix,  such that when  UPLO = 'U' or  'u',
78              the  leading  n by n upper triangular part of the array  A  must
79              contain the upper triangular part of the  symmetric  matrix  and
80              the   strictly   lower triangular part of  A  is not referenced,
81              and when  UPLO = 'L' or 'l', the leading  n by n  lower triangu‐
82              lar  part  of the  array  A must  contain  the  lower triangular
83              part  of the  symmetric matrix and the  strictly upper  triangu‐
84              lar part of  A  is not referenced.  Unchanged on exit.
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86       LDA    - INTEGER.
87              On  entry, LDA specifies the first dimension of A as declared in
88              the calling (sub) program.  When  SIDE = 'L' or  'l'   then  LDA
89              must  be  at least  max( 1, m ), otherwise  LDA must be at least
90              max( 1, n ).  Unchanged on exit.
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92       B      - REAL             array of DIMENSION ( LDB, n ).
93              Before entry, the leading  m by n part of  the  array   B   must
94              contain the matrix B.  Unchanged on exit.
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96       LDB    - INTEGER.
97              On  entry, LDB specifies the first dimension of B as declared in
98              the  calling  (sub)  program.   LDB  must  be  at  least max( 1,
99              m ).  Unchanged on exit.
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101       BETA   - REAL            .
102              On  entry,   BETA   specifies  the scalar  beta.  When  BETA  is
103              supplied as zero then C need not be set on input.  Unchanged  on
104              exit.
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106       C      - REAL             array of DIMENSION ( LDC, n ).
107              Before  entry,  the  leading   m by n  part of the array  C must
108              contain the matrix  C,  except when  beta   is  zero,  in  which
109              case  C  need  not  be  set on entry.  On exit, the array  C  is
110              overwritten by the  m by n updated matrix.
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112       LDC    - INTEGER.
113              On entry, LDC specifies the first dimension of C as declared  in
114              the  calling  (sub)  program.   LDC  must  be  at  least max( 1,
115              m ).  Unchanged on exit.
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117              Level 3 Blas routine.
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119              -- Written on 8-February-1989.  Jack Dongarra, Argonne  National
120              Laboratory.  Iain Duff, AERE Harwell.  Jeremy Du Croz, Numerical
121              Algorithms Group Ltd.   Sven  Hammarling,  Numerical  Algorithms
122              Group Ltd.
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129BLAS routine                     November 2006                        SSYMM(1)