C Collection of code snippets by Arne Vajhøj 
C (from articles on eksperten.dk / vajhoej.dk written sometime between 2004 and now) 
      PROGRAM MULTIARR
      INTEGER*4 N,M
      PARAMETER(N=10,M=10)
      INTEGER*4 I,J
      REAL*8 X(N,M)
      REAL*8 MXSUM
      EXTERNAL MXSUM
      DO 200 I=1,N
        DO 100 J=1,M
          X(I,J)=I*J
100     CONTINUE
200   CONTINUE
      WRITE(*,*) MXSUM(X,N,M)
      END
C
      REAL*8 FUNCTION MXSUM(X,N,M)
      INTEGER*4 N,M
      REAL*8 X(N,M)
      INTEGER*4 I,J
      REAL*8 RES
      RES=0
      DO 200 I=1,N
        DO 100 J=1,M
          RES=RES+X(I,J)
100     CONTINUE
200   CONTINUE
      MXSUM=RES
      END