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MATRA

       SUBROUTINE  MATRA (T, PX,PY,PZ, DX,DY,DZ, ANGLE)
 C$    (Rotation About Arbitrary Axis)
 C$    Return in  T(*,*)  a  4-dimensional  transformation  matrix
 C$    corresponding to  a rotation  by "ANGLE"  degrees about  an
 C$    axis emerging  from a  point (PX,PY,PZ)  and lying  in  the
 C$    direction given by the vector (DX,DY,DZ).  If (DX,DY,DZ) is
 C$    specified as (0,0,0), an error message will be issued and a
 C$    unit  matrix   returned.    A   positive   rotation   angle
 C$    corresponds to a counterclockwise rotation about the  axis.
 C$
 C$    The algorithm  is  given by  D.F.  Rogers and  J.A.  Adams,
 C$    "Mathematical Elements for Computer Graphics",  Mcgraw-Hill
 C$    1976, pp. 54-59.
 C$    (30-JAN-82)