*
* $Id$
*
* $Log$
*
*CMZ :  2.01/00 05/04/2000  14.35.18  by  Marialuigia Ambriola
*CMZ :  2.00/00 03/03/2000  15.39.05  by  Francesco Cafagna
*CMZ :  1.02/00 21/10/99  16.14.45  by  Francesco Cafagna
*CMZ :  1.00/02 25/03/96  15.18.51  by  Francesco Cafagna
*-- Author :    Paolo Papini   16/02/96
      SUBROUTINE FLIN3(V0,V1,V2,V3,F0,F1,F2,F3,V,FF)
************************************************************************
*                                                                      *
*                                 *
* A bit of housekeeping: delete print statement etc. etc., by F. Cafagna
* Called by: GUFLD                                                     *
* Author: Paolo Papini   16/02/96                                      *
*                                                                      *
************************************************************************
#include "gcunit.inc"
*
      REAL V0(3),V1(3),V2(3),V3(3),V(3),FF
      REAL F0,F1,F2,F3,DX,DY,DZ,X1,X2,X3,Y1,Y2,Y3,Z1,Z2,Z3,DET,
     +     S1,S3,S4
*
      F1=F1-F0
      F2=F2-F0
      F3=F3-F0
      DX=V(1)-V0(1)
      DY=V(2)-V0(2)
      DZ=V(3)-V0(3)
      X1=V1(1)-V0(1)
      X2=V2(1)-V0(1)
      X3=V3(1)-V0(1)
      Y1=V1(2)-V0(2)
      Y2=V2(2)-V0(2)
      Y3=V3(2)-V0(2)
      Z1=V1(3)-V0(3)
      Z2=V2(3)-V0(3)
      Z3=V3(3)-V0(3)
      DET=X1*Y2*Z3+Y1*Z2*X3+Z1*X2*Y3-Z1*Y2*X3-Z2*Y3*X1-Z3*Y1*X2
      S1=F1*(Y2*Z3-Z2*Y3)+F2*(Z1*Y3-Z3*Y1)+F3*(Y1*Z2-Z1*Y2)
      S2=F1*(Z2*X3-Z3*X2)+F2*(X1*Z3-Z1*X3)+F3*(Z1*X2-Z2*X1)
      S3=F1*(X2*Y3-Y2*X3)+F2*(Y1*X3-Y3*X1)+F3*(X1*Y2-Y1*X2)
      IF(DET.EQ.0.) THEN
*
* GMAIL routine used
*
         CHMAIL=' flin3 ERROR: MATRIX DETERMINANT EQUAL ZERO'
         CALL GMAIL(1,0)
         FF=F0
         RETURN
      END IF
      FF=F0+(S1*DX+S2*DY+S3*DZ)/DET
      RETURN
      END