C MULAB     SOURCE    CB215821  26/08/24    21:17:26     12622          


      SUBROUTINE MULAB(A,B,R,ia,ja,ib,jb)
C
C     ***************************************************************
C     *                                                             *
C     *            MULTIPLICATION OF TWO MATRIX                     *
C     *            ----------------------------                     *
C     *                                                             *
C     *   INPUT : A,B : MATRIX TO MULTIPLY                          *
C     *                                                             *
C     *  OUTPUT :   R : RESULT                                      *
C     *                                                             *
C     ***************************************************************
C
      IMPLICIT REAL*8 (A-B,D-H,O-Z)
      implicit integer (I-K,M,N)
      implicit logical (L)
      implicit character*10 (C)

      parameter (idimrloc = 441)

      DIMENSION A(ia,ja),B(ib,jb),R(ia,jb)

      dimension rloc(idimrloc)

c     rloc is introduced to allow the results of R to be stored in A or in B
c     Example : Call mulAB(A,B,A,...)
c          or   Call mulAB(A,B,B,...)

      i0 = 0
      i1 = 1
      i3 = 3
      i6 = 6
      r0 = 0.

      if (ia*jb.gt.idimrloc) then
        write(2,3)ia,jb,ia*jb,idimrloc
    3   format(' ERROR from subr. MULAB.'/
     .  '   The dimensions of the result matrix are ',i3,'X',i3,' = ',
     .  i6,' > ',i6/
     .  '   Change idimrloc in MULAB')
        stop
      endif

      if (ja.ne.ib) then
        write(2,2000) ia,ja,ib,jb
        write(*,2000) ia,ja,ib,jb
 2000   format(' ERROR in subr. MULAB.'/
     .         ' It is impossible to multiply a matrix of dimensions',I3
     .  ,' x',i3/
     .         '                           by a matrix of dimensions',I3
     .  ,' x',i3)
        stop
      endif

      iloc = i0
      DO 2001 j=i1,jb
        DO 1 i=i1,ia
          iloc = iloc+i1
          SUM = r0
          DO 2 K=i1,ja
             SUM = SUM+A(i,K)*B(K,j)
    2     continue
          rloc(iloc) = SUM
c       end do
    1   continue
 2001 CONTINUE

      call AequalB(R,rloc,ia,jb,i1,i1)
c     **** *******

      RETURN
      END