REAL*8 FUNCTION TRAB(NRA,NCA,A,LDA,NRB,NCB,B,LDB)
C  This routine computes tr(AB), where A:kxm, B:mxk.
C  Inputs
C  NRA      Rows in A
C  NCA      Columns in A
C  A        Matrix A
C  LDA      Leading dimension of A
C  NRB      Rows in B
C  NCB      Columns in B
C  B        Matrix B
C  LDB      Leading dimension of B
      IMPLICIT REAL*8 (A-H,O-Z)
      DIMENSION A(LDA,NCA),B(LDB,NCB)
      IF((NCA.NE.NRB).OR.(NRA.NE.NCB))GO TO 110
      AA=0.0D0
      DO 10 I=1,NRA
      DO 10 J=1,NCA
   10 AA=AA+A(I,J)*B(J,I)
      TRAB=AA
      RETURN
  110 WRITE(6,115)NRA,NCA,NRB,NCB
  115 FORMAT(' Order inconsistency in TRAB:',4I6)
      STOP
      END