c***********************************************************************
SUBROUTINE NORMALPLANE0(
> X1,Y1,Z1,TAU,
< A,B,C,D)
c Given a point in space, r1=(X1,Y1,Z1), this
c subroutine returns the coefficients defining a plane through the
c equation A*x+B*y+C*z=D, which is normal to the vector r1 and passes
c through the point TAU*r1 (TAU thus being a parameter
c defining how close the plane is to the point).
implicit none
c#@# KKRtags: VORONOI geometry
c Input:
REAL*8 X1,Y1,Z1,TAU
c Output:
REAL*8 A,B,C,D
c Inside:
c The plane is defined by
c (A,B,C)*(X,Y,Z) = D = (tau * r1)**2
c so A,B,C are the coords. of the vector tau * r1.
c If tau=0 (plane passes through the origin), then D=0.
IF (TAU.NE.0.D0) THEN
A = TAU * X1
B = TAU * Y1
C = TAU * Z1
D = A*A + B*B + C*C
ELSE
A = X1
B = Y1
C = Z1
D = 0.D0
ENDIF
RETURN
END
