C         SUBROUTINE TO CALCULATE PARTIAL SUMS  PSUM
C
          SUBROUTINE PRTSUM(MODULE,ISON)
          COMMON/CENTS/C(3,15)
          COMMON/PROD/PAC(3,3,15)
          COMMON/SUMIT/PSUM(3,16,5)
          COMMON/LINKIT/ISTRT,LINKS(6,15)
          IF(MODULE.EQ.0)GO TO 99
C         PICK OUT PARENT
          IMOD=LINKS(1,MODULE)
          I=1
10        I=I+1
          NUMSON=LINKS(I,MODULE)
          IF(NUMSON.NE.ISON)GO TO 10
          NUMSON=I-1
          IF(IMOD.EQ.0)GO TO 12
          I=1
11        I=I+1
          INSON=LINKS(I,IMOD)
          IF(INSON.NE.MODULE)GO TO 11
          INSON=I-1
          GO TO 13
12        INSON=1
          IMOD=16
13        DO 69 J=1,3
          SUM=0.
          DO 68 I=1,3
68        SUM=PAC(J,I,MODULE)*C(I,ISON)+SUM
69        PSUM(J,MODULE,NUMSON)=SUM
          DO 67 I=1,3
67    PSUM(I,MODULE,NUMSON)=PSUM(I,MODULE,NUMSON)+PSUM(I,
     2IMOD,INSON)
99        RETURN
          END