SSYMM  performs one of the matrix-matrix operations


    C := alpha*A*B + beta*C,


 or


    C := alpha*B*A + beta*C,


 where alpha and beta are scalars,  A is a symmetric matrix and  B and


 C are  m by n matrices.

SIDE

          SIDE is CHARACTER*1


           On entry,  SIDE  specifies whether  the  symmetric matrix  A


           appears on the  left or right  in the  operation as follows:


              SIDE = 'L' or 'l'   C := alpha*A*B + beta*C,


              SIDE = 'R' or 'r'   C := alpha*B*A + beta*C,

UPLO

          UPLO is CHARACTER*1


           On  entry,   UPLO  specifies  whether  the  upper  or  lower


           triangular  part  of  the  symmetric  matrix   A  is  to  be


           referenced as follows:


              UPLO = 'U' or 'u'   Only the upper triangular part of the


                                  symmetric matrix is to be referenced.


              UPLO = 'L' or 'l'   Only the lower triangular part of the


                                  symmetric matrix is to be referenced.

M

          M is INTEGER


           On entry,  M  specifies the number of rows of the matrix  C.


           M  must be at least zero.

N

          N is INTEGER


           On entry, N specifies the number of columns of the matrix C.


           N  must be at least zero.

ALPHA

          ALPHA is REAL


           On entry, ALPHA specifies the scalar alpha.

A

          A is REAL array, dimension ( LDA, ka ), where ka is


           m  when  SIDE = 'L' or 'l'  and is  n otherwise.


           Before entry  with  SIDE = 'L' or 'l',  the  m by m  part of


           the array  A  must contain the  symmetric matrix,  such that


           when  UPLO = 'U' or 'u', the leading m by m upper triangular


           part of the array  A  must contain the upper triangular part


           of the  symmetric matrix and the  strictly  lower triangular


           part of  A  is not referenced,  and when  UPLO = 'L' or 'l',


           the leading  m by m  lower triangular part  of the  array  A


           must  contain  the  lower triangular part  of the  symmetric


           matrix and the  strictly upper triangular part of  A  is not


           referenced.


           Before entry  with  SIDE = 'R' or 'r',  the  n by n  part of


           the array  A  must contain the  symmetric matrix,  such that


           when  UPLO = 'U' or 'u', the leading n by n upper triangular


           part of the array  A  must contain the upper triangular part


           of the  symmetric matrix and the  strictly  lower triangular


           part of  A  is not referenced,  and when  UPLO = 'L' or 'l',


           the leading  n by n  lower triangular part  of the  array  A


           must  contain  the  lower triangular part  of the  symmetric


           matrix and the  strictly upper triangular part of  A  is not


           referenced.

LDA

          LDA is INTEGER


           On entry, LDA specifies the first dimension of A as declared


           in the calling (sub) program.  When  SIDE = 'L' or 'l'  then


           LDA must be at least  max( 1, m ), otherwise  LDA must be at


           least  max( 1, n ).

B

          B is REAL array, dimension ( LDB, N )


           Before entry, the leading  m by n part of the array  B  must


           contain the matrix B.

LDB

          LDB is INTEGER


           On entry, LDB specifies the first dimension of B as declared


           in  the  calling  (sub)  program.   LDB  must  be  at  least


           max( 1, m ).

BETA

          BETA is REAL


           On entry,  BETA  specifies the scalar  beta.  When  BETA  is


           supplied as zero then C need not be set on input.

C

          C is REAL array, dimension ( LDC, N )


           Before entry, the leading  m by n  part of the array  C must


           contain the matrix  C,  except when  beta  is zero, in which


           case C need not be set on entry.


           On exit, the array  C  is overwritten by the  m by n updated


           matrix.

LDC

          LDC is INTEGER


           On entry, LDC specifies the first dimension of C as declared


           in  the  calling  (sub)  program.   LDC  must  be  at  least


           max( 1, m ).

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

  Level 3 Blas routine.


  -- Written on 8-February-1989.


     Jack Dongarra, Argonne National Laboratory.


     Iain Duff, AERE Harwell.


     Jeremy Du Croz, Numerical Algorithms Group Ltd.


     Sven Hammarling, Numerical Algorithms Group Ltd.