C^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                
      SUBROUTINE GSFSCA 
C^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                
      IMPLICIT REAL(A-H,O-Y)                                          
      IMPLICIT COMPLEX(Z)                                            
      INCLUDE 'PACVPP' 
C     --------------------TETRAHEDRON VOLUME-------------------------   
      FFF =    RLTV(1,1)*(RLTV(2,2)*RLTV(3,3)-RLTV(3,2)*RLTV(2,3))      
     &      +  RLTV(2,1)*(RLTV(3,2)*RLTV(1,3)-RLTV(1,2)*RLTV(3,3))      
     &      +  RLTV(3,1)*(RLTV(1,2)*RLTV(2,3)-RLTV(2,2)*RLTV(1,3))      
      RVOL = ABS(FFF)                                                   
      RETURN                                                            
      END