      SUBROUTINE NEGPLN(PLN)
      DIMENSION PLN( 306 )
C SUB. CHANGES SIGN OF ASYM. PLN IN S. HEMI.
      DO 2 LL=1, 17
      JLE=(LL-1)* 18
      DO 1 IND=2, 18 ,2
      PLN(JLE+IND)=-PLN(JLE+IND)
1     CONTINUE
2     CONTINUE
C(DEBUGLINE) VERSION CREATED JULY 8 1982 BY J.SELA,NMC.
      RETURN
      END
