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SUBROUTINE CTRMM(SIDE,UPLO,TRANSA,DIAG,M,N,ALPHA,A,LDA,B,LDB)
* .. Scalar Arguments ..
COMPLEX ALPHA
INTEGER LDA,LDB,M,N
CHARACTER DIAG,SIDE,TRANSA,UPLO
* ..
* .. Array Arguments ..
COMPLEX A(LDA,*),B(LDB,*)
* ..
*
* Purpose
* =======
*
* CTRMM performs one of the matrix-matrix operations
*
* B := alpha*op( A )*B, or B := alpha*B*op( A )
*
* where alpha is a scalar, B is an m by n matrix, A is a unit, or
* non-unit, upper or lower triangular matrix and op( A ) is one of
*
* op( A ) = A or op( A ) = A' or op( A ) = conjg( A' ).
*
* Arguments
* ==========
*
* SIDE - CHARACTER*1.
* On entry, SIDE specifies whether op( A ) multiplies B from
* the left or right as follows:
*
* SIDE = 'L' or 'l' B := alpha*op( A )*B.
*
* SIDE = 'R' or 'r' B := alpha*B*op( A ).
*
* Unchanged on exit.
*
* UPLO - CHARACTER*1.
* On entry, UPLO specifies whether the matrix A is an upper or
* lower triangular matrix as follows:
*
* UPLO = 'U' or 'u' A is an upper triangular matrix.
*
* UPLO = 'L' or 'l' A is a lower triangular matrix.
*
* Unchanged on exit.
*
* TRANSA - CHARACTER*1.
* On entry, TRANSA specifies the form of op( A ) to be used in
* the matrix multiplication as follows:
*
* TRANSA = 'N' or 'n' op( A ) = A.
*
* TRANSA = 'T' or 't' op( A ) = A'.
*
* TRANSA = 'C' or 'c' op( A ) = conjg( A' ).
*
* Unchanged on exit.
*
* DIAG - CHARACTER*1.
* On entry, DIAG specifies whether or not A is unit triangular
* as follows:
*
* DIAG = 'U' or 'u' A is assumed to be unit triangular.
*
* DIAG = 'N' or 'n' A is not assumed to be unit
* triangular.
*
* Unchanged on exit.
*
* M - INTEGER.
* On entry, M specifies the number of rows of B. M must be at
* least zero.
* Unchanged on exit.
*
* N - INTEGER.
* On entry, N specifies the number of columns of B. N must be
* at least zero.
* Unchanged on exit.
*
* ALPHA - COMPLEX .
* On entry, ALPHA specifies the scalar alpha. When alpha is
* zero then A is not referenced and B need not be set before
* entry.
* Unchanged on exit.
*
* A - COMPLEX array of DIMENSION ( LDA, k ), where k is m
* when SIDE = 'L' or 'l' and is n when SIDE = 'R' or 'r'.
* Before entry with UPLO = 'U' or 'u', the leading k by k
* upper triangular part of the array A must contain the upper
* triangular matrix and the strictly lower triangular part of
* A is not referenced.
* Before entry with UPLO = 'L' or 'l', the leading k by k
* lower triangular part of the array A must contain the lower
* triangular matrix and the strictly upper triangular part of
* A is not referenced.
* Note that when DIAG = 'U' or 'u', the diagonal elements of
* A are not referenced either, but are assumed to be unity.
* Unchanged on exit.
*
* LDA - 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 ), when SIDE = 'R' or 'r'
* then LDA must be at least max( 1, n ).
* Unchanged on exit.
*
* B - COMPLEX array of DIMENSION ( LDB, n ).
* Before entry, the leading m by n part of the array B must
* contain the matrix B, and on exit is overwritten by the
* transformed matrix.
*
* LDB - 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 ).
* Unchanged on exit.
*
*
* 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.
*
*
* .. External Functions ..
LOGICAL LSAME
EXTERNAL LSAME
* ..
* .. External Subroutines ..
EXTERNAL XERBLA
* ..
* .. Intrinsic Functions ..
INTRINSIC CONJG,MAX
* ..
* .. Local Scalars ..
COMPLEX TEMP
INTEGER I,INFO,J,K,NROWA
LOGICAL LSIDE,NOCONJ,NOUNIT,UPPER
* ..
* .. Parameters ..
COMPLEX ONE
PARAMETER (ONE= (1.0E+0,0.0E+0))
COMPLEX ZERO
PARAMETER (ZERO= (0.0E+0,0.0E+0))
* ..
*
* Test the input parameters.
*
LSIDE = LSAME(SIDE,'L')
IF (LSIDE) THEN
NROWA = M
ELSE
NROWA = N
END IF
NOCONJ = LSAME(TRANSA,'T')
NOUNIT = LSAME(DIAG,'N')
UPPER = LSAME(UPLO,'U')
*
INFO = 0
IF ((.NOT.LSIDE) .AND. (.NOT.LSAME(SIDE,'R'))) THEN
INFO = 1
ELSE IF ((.NOT.UPPER) .AND. (.NOT.LSAME(UPLO,'L'))) THEN
INFO = 2
ELSE IF ((.NOT.LSAME(TRANSA,'N')) .AND.
+ (.NOT.LSAME(TRANSA,'T')) .AND.
+ (.NOT.LSAME(TRANSA,'C'))) THEN
INFO = 3
ELSE IF ((.NOT.LSAME(DIAG,'U')) .AND. (.NOT.LSAME(DIAG,'N'))) THEN
INFO = 4
ELSE IF (M.LT.0) THEN
INFO = 5
ELSE IF (N.LT.0) THEN
INFO = 6
ELSE IF (LDA.LT.MAX(1,NROWA)) THEN
INFO = 9
ELSE IF (LDB.LT.MAX(1,M)) THEN
INFO = 11
END IF
IF (INFO.NE.0) THEN
CALL XERBLA('CTRMM ',INFO)
RETURN
END IF
*
* Quick return if possible.
*
IF (M.EQ.0 .OR. N.EQ.0) RETURN
*
* And when alpha.eq.zero.
*
IF (ALPHA.EQ.ZERO) THEN
DO 20 J = 1,N
DO 10 I = 1,M
B(I,J) = ZERO
10 CONTINUE
20 CONTINUE
RETURN
END IF
*
* Start the operations.
*
IF (LSIDE) THEN
IF (LSAME(TRANSA,'N')) THEN
*
* Form B := alpha*A*B.
*
IF (UPPER) THEN
DO 50 J = 1,N
DO 40 K = 1,M
IF (B(K,J).NE.ZERO) THEN
TEMP = ALPHA*B(K,J)
DO 30 I = 1,K - 1
B(I,J) = B(I,J) + TEMP*A(I,K)
30 CONTINUE
IF (NOUNIT) TEMP = TEMP*A(K,K)
B(K,J) = TEMP
END IF
40 CONTINUE
50 CONTINUE
ELSE
DO 80 J = 1,N
DO 70 K = M,1,-1
IF (B(K,J).NE.ZERO) THEN
TEMP = ALPHA*B(K,J)
B(K,J) = TEMP
IF (NOUNIT) B(K,J) = B(K,J)*A(K,K)
DO 60 I = K + 1,M
B(I,J) = B(I,J) + TEMP*A(I,K)
60 CONTINUE
END IF
70 CONTINUE
80 CONTINUE
END IF
ELSE
*
* Form B := alpha*A'*B or B := alpha*conjg( A' )*B.
*
IF (UPPER) THEN
DO 120 J = 1,N
DO 110 I = M,1,-1
TEMP = B(I,J)
IF (NOCONJ) THEN
IF (NOUNIT) TEMP = TEMP*A(I,I)
DO 90 K = 1,I - 1
TEMP = TEMP + A(K,I)*B(K,J)
90 CONTINUE
ELSE
IF (NOUNIT) TEMP = TEMP*CONJG(A(I,I))
DO 100 K = 1,I - 1
TEMP = TEMP + CONJG(A(K,I))*B(K,J)
100 CONTINUE
END IF
B(I,J) = ALPHA*TEMP
110 CONTINUE
120 CONTINUE
ELSE
DO 160 J = 1,N
DO 150 I = 1,M
TEMP = B(I,J)
IF (NOCONJ) THEN
IF (NOUNIT) TEMP = TEMP*A(I,I)
DO 130 K = I + 1,M
TEMP = TEMP + A(K,I)*B(K,J)
130 CONTINUE
ELSE
IF (NOUNIT) TEMP = TEMP*CONJG(A(I,I))
DO 140 K = I + 1,M
TEMP = TEMP + CONJG(A(K,I))*B(K,J)
140 CONTINUE
END IF
B(I,J) = ALPHA*TEMP
150 CONTINUE
160 CONTINUE
END IF
END IF
ELSE
IF (LSAME(TRANSA,'N')) THEN
*
* Form B := alpha*B*A.
*
IF (UPPER) THEN
DO 200 J = N,1,-1
TEMP = ALPHA
IF (NOUNIT) TEMP = TEMP*A(J,J)
DO 170 I = 1,M
B(I,J) = TEMP*B(I,J)
170 CONTINUE
DO 190 K = 1,J - 1
IF (A(K,J).NE.ZERO) THEN
TEMP = ALPHA*A(K,J)
DO 180 I = 1,M
B(I,J) = B(I,J) + TEMP*B(I,K)
180 CONTINUE
END IF
190 CONTINUE
200 CONTINUE
ELSE
DO 240 J = 1,N
TEMP = ALPHA
IF (NOUNIT) TEMP = TEMP*A(J,J)
DO 210 I = 1,M
B(I,J) = TEMP*B(I,J)
210 CONTINUE
DO 230 K = J + 1,N
IF (A(K,J).NE.ZERO) THEN
TEMP = ALPHA*A(K,J)
DO 220 I = 1,M
B(I,J) = B(I,J) + TEMP*B(I,K)
220 CONTINUE
END IF
230 CONTINUE
240 CONTINUE
END IF
ELSE
*
* Form B := alpha*B*A' or B := alpha*B*conjg( A' ).
*
IF (UPPER) THEN
DO 280 K = 1,N
DO 260 J = 1,K - 1
IF (A(J,K).NE.ZERO) THEN
IF (NOCONJ) THEN
TEMP = ALPHA*A(J,K)
ELSE
TEMP = ALPHA*CONJG(A(J,K))
END IF
DO 250 I = 1,M
B(I,J) = B(I,J) + TEMP*B(I,K)
250 CONTINUE
END IF
260 CONTINUE
TEMP = ALPHA
IF (NOUNIT) THEN
IF (NOCONJ) THEN
TEMP = TEMP*A(K,K)
ELSE
TEMP = TEMP*CONJG(A(K,K))
END IF
END IF
IF (TEMP.NE.ONE) THEN
DO 270 I = 1,M
B(I,K) = TEMP*B(I,K)
270 CONTINUE
END IF
280 CONTINUE
ELSE
DO 320 K = N,1,-1
DO 300 J = K + 1,N
IF (A(J,K).NE.ZERO) THEN
IF (NOCONJ) THEN
TEMP = ALPHA*A(J,K)
ELSE
TEMP = ALPHA*CONJG(A(J,K))
END IF
DO 290 I = 1,M
B(I,J) = B(I,J) + TEMP*B(I,K)
290 CONTINUE
END IF
300 CONTINUE
TEMP = ALPHA
IF (NOUNIT) THEN
IF (NOCONJ) THEN
TEMP = TEMP*A(K,K)
ELSE
TEMP = TEMP*CONJG(A(K,K))
END IF
END IF
IF (TEMP.NE.ONE) THEN
DO 310 I = 1,M
B(I,K) = TEMP*B(I,K)
310 CONTINUE
END IF
320 CONTINUE
END IF
END IF
END IF
*
RETURN
*
* End of CTRMM .
*
END
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