```      SUBROUTINE ZGEMM(TRANSA,TRANSB,M,N,K,ALPHA,A,LDA,B,LDB,BETA,C,LDC)
*     .. Scalar Arguments ..
DOUBLE COMPLEX ALPHA,BETA
INTEGER K,LDA,LDB,LDC,M,N
CHARACTER TRANSA,TRANSB
*     ..
*     .. Array Arguments ..
DOUBLE COMPLEX A(LDA,*),B(LDB,*),C(LDC,*)
*     ..
*
*  Purpose
*  =======
*
*  ZGEMM  performs one of the matrix-matrix operations
*
*     C := alpha*op( A )*op( B ) + beta*C,
*
*  where  op( X ) is one of
*
*     op( X ) = X   or   op( X ) = X'   or   op( X ) = conjg( X' ),
*
*  alpha and beta are scalars, and A, B and C are matrices, with op( A )
*  an m by k matrix,  op( B )  a  k by n matrix and  C an m by n matrix.
*
*  Arguments
*  ==========
*
*  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.
*
*  TRANSB - CHARACTER*1.
*           On entry, TRANSB specifies the form of op( B ) to be used in
*           the matrix multiplication as follows:
*
*              TRANSB = 'N' or 'n',  op( B ) = B.
*
*              TRANSB = 'T' or 't',  op( B ) = B'.
*
*              TRANSB = 'C' or 'c',  op( B ) = conjg( B' ).
*
*           Unchanged on exit.
*
*  M      - INTEGER.
*           On entry,  M  specifies  the number  of rows  of the  matrix
*           op( A )  and of the  matrix  C.  M  must  be at least  zero.
*           Unchanged on exit.
*
*  N      - INTEGER.
*           On entry,  N  specifies the number  of columns of the matrix
*           op( B ) and the number of columns of the matrix C. N must be
*           at least zero.
*           Unchanged on exit.
*
*  K      - INTEGER.
*           On entry,  K  specifies  the number of columns of the matrix
*           op( A ) and the number of rows of the matrix op( B ). K must
*           be at least  zero.
*           Unchanged on exit.
*
*  ALPHA  - COMPLEX*16      .
*           On entry, ALPHA specifies the scalar alpha.
*           Unchanged on exit.
*
*  A      - COMPLEX*16       array of DIMENSION ( LDA, ka ), where ka is
*           k  when  TRANSA = 'N' or 'n',  and is  m  otherwise.
*           Before entry with  TRANSA = 'N' or 'n',  the leading  m by k
*           part of the array  A  must contain the matrix  A,  otherwise
*           the leading  k by m  part of the array  A  must contain  the
*           matrix A.
*           Unchanged on exit.
*
*  LDA    - INTEGER.
*           On entry, LDA specifies the first dimension of A as declared
*           in the calling (sub) program. When  TRANSA = 'N' or 'n' then
*           LDA must be at least  max( 1, m ), otherwise  LDA must be at
*           least  max( 1, k ).
*           Unchanged on exit.
*
*  B      - COMPLEX*16       array of DIMENSION ( LDB, kb ), where kb is
*           n  when  TRANSB = 'N' or 'n',  and is  k  otherwise.
*           Before entry with  TRANSB = 'N' or 'n',  the leading  k by n
*           part of the array  B  must contain the matrix  B,  otherwise
*           the leading  n by k  part of the array  B  must contain  the
*           matrix B.
*           Unchanged on exit.
*
*  LDB    - INTEGER.
*           On entry, LDB specifies the first dimension of B as declared
*           in the calling (sub) program. When  TRANSB = 'N' or 'n' then
*           LDB must be at least  max( 1, k ), otherwise  LDB must be at
*           least  max( 1, n ).
*           Unchanged on exit.
*
*  BETA   - COMPLEX*16      .
*           On entry,  BETA  specifies the scalar  beta.  When  BETA  is
*           supplied as zero then C need not be set on input.
*           Unchanged on exit.
*
*  C      - COMPLEX*16       array of 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  matrix
*           ( alpha*op( A )*op( B ) + beta*C ).
*
*  LDC    - 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 ).
*           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 DCONJG,MAX
*     ..
*     .. Local Scalars ..
DOUBLE COMPLEX TEMP
INTEGER I,INFO,J,L,NCOLA,NROWA,NROWB
LOGICAL CONJA,CONJB,NOTA,NOTB
*     ..
*     .. Parameters ..
DOUBLE COMPLEX ONE
PARAMETER (ONE= (1.0D+0,0.0D+0))
DOUBLE COMPLEX ZERO
PARAMETER (ZERO= (0.0D+0,0.0D+0))
*     ..
*
*     Set  NOTA  and  NOTB  as  true if  A  and  B  respectively are not
*     conjugated or transposed, set  CONJA and CONJB  as true if  A  and
*     B  respectively are to be  transposed but  not conjugated  and set
*     NROWA, NCOLA and  NROWB  as the number of rows and  columns  of  A
*     and the number of rows of  B  respectively.
*
NOTA = LSAME(TRANSA,'N')
NOTB = LSAME(TRANSB,'N')
CONJA = LSAME(TRANSA,'C')
CONJB = LSAME(TRANSB,'C')
IF (NOTA) THEN
NROWA = M
NCOLA = K
ELSE
NROWA = K
NCOLA = M
END IF
IF (NOTB) THEN
NROWB = K
ELSE
NROWB = N
END IF
*
*     Test the input parameters.
*
INFO = 0
IF ((.NOT.NOTA) .AND. (.NOT.CONJA) .AND.
+    (.NOT.LSAME(TRANSA,'T'))) THEN
INFO = 1
ELSE IF ((.NOT.NOTB) .AND. (.NOT.CONJB) .AND.
+         (.NOT.LSAME(TRANSB,'T'))) THEN
INFO = 2
ELSE IF (M.LT.0) THEN
INFO = 3
ELSE IF (N.LT.0) THEN
INFO = 4
ELSE IF (K.LT.0) THEN
INFO = 5
ELSE IF (LDA.LT.MAX(1,NROWA)) THEN
INFO = 8
ELSE IF (LDB.LT.MAX(1,NROWB)) THEN
INFO = 10
ELSE IF (LDC.LT.MAX(1,M)) THEN
INFO = 13
END IF
IF (INFO.NE.0) THEN
CALL XERBLA('ZGEMM ',INFO)
RETURN
END IF
*
*     Quick return if possible.
*
IF ((M.EQ.0) .OR. (N.EQ.0) .OR.
+    (((ALPHA.EQ.ZERO).OR. (K.EQ.0)).AND. (BETA.EQ.ONE))) RETURN
*
*     And when  alpha.eq.zero.
*
IF (ALPHA.EQ.ZERO) THEN
IF (BETA.EQ.ZERO) THEN
DO 20 J = 1,N
DO 10 I = 1,M
C(I,J) = ZERO
10             CONTINUE
20         CONTINUE
ELSE
DO 40 J = 1,N
DO 30 I = 1,M
C(I,J) = BETA*C(I,J)
30             CONTINUE
40         CONTINUE
END IF
RETURN
END IF
*
*     Start the operations.
*
IF (NOTB) THEN
IF (NOTA) THEN
*
*           Form  C := alpha*A*B + beta*C.
*
DO 90 J = 1,N
IF (BETA.EQ.ZERO) THEN
DO 50 I = 1,M
C(I,J) = ZERO
50                 CONTINUE
ELSE IF (BETA.NE.ONE) THEN
DO 60 I = 1,M
C(I,J) = BETA*C(I,J)
60                 CONTINUE
END IF
DO 80 L = 1,K
IF (B(L,J).NE.ZERO) THEN
TEMP = ALPHA*B(L,J)
DO 70 I = 1,M
C(I,J) = C(I,J) + TEMP*A(I,L)
70                     CONTINUE
END IF
80             CONTINUE
90         CONTINUE
ELSE IF (CONJA) THEN
*
*           Form  C := alpha*conjg( A' )*B + beta*C.
*
DO 120 J = 1,N
DO 110 I = 1,M
TEMP = ZERO
DO 100 L = 1,K
TEMP = TEMP + DCONJG(A(L,I))*B(L,J)
100                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
110             CONTINUE
120         CONTINUE
ELSE
*
*           Form  C := alpha*A'*B + beta*C
*
DO 150 J = 1,N
DO 140 I = 1,M
TEMP = ZERO
DO 130 L = 1,K
TEMP = TEMP + A(L,I)*B(L,J)
130                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
140             CONTINUE
150         CONTINUE
END IF
ELSE IF (NOTA) THEN
IF (CONJB) THEN
*
*           Form  C := alpha*A*conjg( B' ) + beta*C.
*
DO 200 J = 1,N
IF (BETA.EQ.ZERO) THEN
DO 160 I = 1,M
C(I,J) = ZERO
160                 CONTINUE
ELSE IF (BETA.NE.ONE) THEN
DO 170 I = 1,M
C(I,J) = BETA*C(I,J)
170                 CONTINUE
END IF
DO 190 L = 1,K
IF (B(J,L).NE.ZERO) THEN
TEMP = ALPHA*DCONJG(B(J,L))
DO 180 I = 1,M
C(I,J) = C(I,J) + TEMP*A(I,L)
180                     CONTINUE
END IF
190             CONTINUE
200         CONTINUE
ELSE
*
*           Form  C := alpha*A*B'          + beta*C
*
DO 250 J = 1,N
IF (BETA.EQ.ZERO) THEN
DO 210 I = 1,M
C(I,J) = ZERO
210                 CONTINUE
ELSE IF (BETA.NE.ONE) THEN
DO 220 I = 1,M
C(I,J) = BETA*C(I,J)
220                 CONTINUE
END IF
DO 240 L = 1,K
IF (B(J,L).NE.ZERO) THEN
TEMP = ALPHA*B(J,L)
DO 230 I = 1,M
C(I,J) = C(I,J) + TEMP*A(I,L)
230                     CONTINUE
END IF
240             CONTINUE
250         CONTINUE
END IF
ELSE IF (CONJA) THEN
IF (CONJB) THEN
*
*           Form  C := alpha*conjg( A' )*conjg( B' ) + beta*C.
*
DO 280 J = 1,N
DO 270 I = 1,M
TEMP = ZERO
DO 260 L = 1,K
TEMP = TEMP + DCONJG(A(L,I))*DCONJG(B(J,L))
260                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
270             CONTINUE
280         CONTINUE
ELSE
*
*           Form  C := alpha*conjg( A' )*B' + beta*C
*
DO 310 J = 1,N
DO 300 I = 1,M
TEMP = ZERO
DO 290 L = 1,K
TEMP = TEMP + DCONJG(A(L,I))*B(J,L)
290                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
300             CONTINUE
310         CONTINUE
END IF
ELSE
IF (CONJB) THEN
*
*           Form  C := alpha*A'*conjg( B' ) + beta*C
*
DO 340 J = 1,N
DO 330 I = 1,M
TEMP = ZERO
DO 320 L = 1,K
TEMP = TEMP + A(L,I)*DCONJG(B(J,L))
320                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
330             CONTINUE
340         CONTINUE
ELSE
*
*           Form  C := alpha*A'*B' + beta*C
*
DO 370 J = 1,N
DO 360 I = 1,M
TEMP = ZERO
DO 350 L = 1,K
TEMP = TEMP + A(L,I)*B(J,L)
350                 CONTINUE
IF (BETA.EQ.ZERO) THEN
C(I,J) = ALPHA*TEMP
ELSE
C(I,J) = ALPHA*TEMP + BETA*C(I,J)
END IF
360             CONTINUE
370         CONTINUE
END IF
END IF
*
RETURN
*
*     End of ZGEMM .
*
END

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