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Annotation of rpl/lapack/lapack/zlarcm.f, revision 1.7

1.1       bertrand    1:       SUBROUTINE ZLARCM( M, N, A, LDA, B, LDB, C, LDC, RWORK )
                      2: *
                      3: *  -- LAPACK auxiliary routine (version 3.2) --
                      4: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
                      5: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
                      6: *     November 2006
                      7: *
                      8: *     .. Scalar Arguments ..
                      9:       INTEGER            LDA, LDB, LDC, M, N
                     10: *     ..
                     11: *     .. Array Arguments ..
                     12:       DOUBLE PRECISION   A( LDA, * ), RWORK( * )
                     13:       COMPLEX*16         B( LDB, * ), C( LDC, * )
                     14: *     ..
                     15: *
                     16: *  Purpose
                     17: *  =======
                     18: *
                     19: *  ZLARCM performs a very simple matrix-matrix multiplication:
                     20: *           C := A * B,
                     21: *  where A is M by M and real; B is M by N and complex;
                     22: *  C is M by N and complex.
                     23: *
                     24: *  Arguments
                     25: *  =========
                     26: *
                     27: *  M       (input) INTEGER
                     28: *          The number of rows of the matrix A and of the matrix C.
                     29: *          M >= 0.
                     30: *
                     31: *  N       (input) INTEGER
                     32: *          The number of columns and rows of the matrix B and
                     33: *          the number of columns of the matrix C.
                     34: *          N >= 0.
                     35: *
                     36: *  A       (input) DOUBLE PRECISION array, dimension (LDA, M)
                     37: *          A contains the M by M matrix A.
                     38: *
                     39: *  LDA     (input) INTEGER
                     40: *          The leading dimension of the array A. LDA >=max(1,M).
                     41: *
                     42: *  B       (input) DOUBLE PRECISION array, dimension (LDB, N)
                     43: *          B contains the M by N matrix B.
                     44: *
                     45: *  LDB     (input) INTEGER
                     46: *          The leading dimension of the array B. LDB >=max(1,M).
                     47: *
                     48: *  C       (input) COMPLEX*16 array, dimension (LDC, N)
                     49: *          C contains the M by N matrix C.
                     50: *
                     51: *  LDC     (input) INTEGER
                     52: *          The leading dimension of the array C. LDC >=max(1,M).
                     53: *
                     54: *  RWORK   (workspace) DOUBLE PRECISION array, dimension (2*M*N)
                     55: *
                     56: *  =====================================================================
                     57: *
                     58: *     .. Parameters ..
                     59:       DOUBLE PRECISION   ONE, ZERO
                     60:       PARAMETER          ( ONE = 1.0D0, ZERO = 0.0D0 )
                     61: *     ..
                     62: *     .. Local Scalars ..
                     63:       INTEGER            I, J, L
                     64: *     ..
                     65: *     .. Intrinsic Functions ..
                     66:       INTRINSIC          DBLE, DCMPLX, DIMAG
                     67: *     ..
                     68: *     .. External Subroutines ..
                     69:       EXTERNAL           DGEMM
                     70: *     ..
                     71: *     .. Executable Statements ..
                     72: *
                     73: *     Quick return if possible.
                     74: *
                     75:       IF( ( M.EQ.0 ) .OR. ( N.EQ.0 ) )
                     76:      $   RETURN
                     77: *
                     78:       DO 20 J = 1, N
                     79:          DO 10 I = 1, M
                     80:             RWORK( ( J-1 )*M+I ) = DBLE( B( I, J ) )
                     81:    10    CONTINUE
                     82:    20 CONTINUE
                     83: *
                     84:       L = M*N + 1
                     85:       CALL DGEMM( 'N', 'N', M, N, M, ONE, A, LDA, RWORK, M, ZERO,
                     86:      $            RWORK( L ), M )
                     87:       DO 40 J = 1, N
                     88:          DO 30 I = 1, M
                     89:             C( I, J ) = RWORK( L+( J-1 )*M+I-1 )
                     90:    30    CONTINUE
                     91:    40 CONTINUE
                     92: *
                     93:       DO 60 J = 1, N
                     94:          DO 50 I = 1, M
                     95:             RWORK( ( J-1 )*M+I ) = DIMAG( B( I, J ) )
                     96:    50    CONTINUE
                     97:    60 CONTINUE
                     98:       CALL DGEMM( 'N', 'N', M, N, M, ONE, A, LDA, RWORK, M, ZERO,
                     99:      $            RWORK( L ), M )
                    100:       DO 80 J = 1, N
                    101:          DO 70 I = 1, M
                    102:             C( I, J ) = DCMPLX( DBLE( C( I, J ) ),
                    103:      $                  RWORK( L+( J-1 )*M+I-1 ) )
                    104:    70    CONTINUE
                    105:    80 CONTINUE
                    106: *
                    107:       RETURN
                    108: *
                    109: *     End of ZLARCM
                    110: *
                    111:       END