subroutine aptvplp (ax, ay, az, bx, by, bz, np, tol,
& cx, cy, cz, clen, nerr)
ccbeg.
cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
c
c SUBROUTINE APTVPLP
c
c call aptvplp (ax, ay, az, bx, by, bz, np, tol,
c & cx, cy, cz, clen, nerr)
c
c Version: aptvplp Updated 1990 November 26 10:00.
c aptvplp Originated 1990 April 5 14:30.
c
c Author: Arthur L. Edwards, LLNL, L-298, Telephone (925) 422-4123.
c
c
c Purpose: To find, for each of np sets of input data, the projection
c c = (cx, cy, cz) of the vector a = (ax, ay, az) on the plane
c with normal vector b = (bx, by, bz), and clen, the magnitude
c of vector "c". If the magnitude of vector "b" is too small,
c the orientation of the plane is indeterminate, and the
c returned value of clen will be -1.e+99. The components of
c vector "c" may be truncated to zero, if less than the estimated
c error in their calculation, based on tol.
c Flag nerr indicates any input error.
c
c Input: ax, ay, az, bx, by, bz, np, tol.
c
c Output: cx, cy, cz, clen, nerr.
c
c Calls: aptvadd, aptvdot, aptvunb
c
c
c Glossary:
c
c ax,ay,az Input The x, y, z components of vector "a". Size np.
c
c bx,by,bz Input The x, y, z components of vector "b". Size np.
c Normal to the projection plane. If too small,
c based on tol, to determine the orientation of the
c plane, clen will be returned as -1.e+99.
c
c clen Output The magnitude of vector "c". Size np.
c Zero if vector "a" is perpendicular to the plane.
c Will be -1.e+99 if vector "b" is too small.
c
c cx,cy,cz Output The x, y, z components of vector "c". Size np.
c The projection of vector "a" in the plane with
c normal vector "b". Each component may be truncated
c to zero, if less than the estimated error in its
c calculation, based on tol. If vector "b" is too
c small, based on tol, vector "c" will be equal to
c vector "a", but clen will be -1.e+99.
c
c nerr Output Indicates an input error, if not 0. See clen.
c 1 if np is not positive.
c
c np Input Size of arrays.
c
c tol Input Numerical tolerance limit.
c On Cray computers, recommend 1.e-5 to 1.e-11.
c
cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
ccend.
c.... Dimensioned arguments.
c---- Component x of vector "a".
dimension ax (1)
c---- Component y of vector "a".
dimension ay (1)
c---- Component z of vector "a".
dimension az (1)
c---- Component x of vector "b".
dimension bx (1)
c---- Component y of vector "b".
dimension by (1)
c---- Component z of vector "b".
dimension bz (1)
c---- Magnitude of vector "c".
dimension clen (1)
c---- Component x of vector "c".
dimension cx (1)
c---- Component y of vector "c".
dimension cy (1)
c---- Component z of vector "c".
dimension cz (1)
c.... Local variables.
c---- Component of vector "a" prll to "b".
common /laptvplp/ ahb (64)
c---- A very big number.
common /laptvplp/ big
c---- Magnitude of normal vector "b".
common /laptvplp/ blen (64)
c---- Component x of unit normal vector.
common /laptvplp/ hbx (64)
c---- Component y of unit normal vector.
common /laptvplp/ hby (64)
c---- Component z of unit normal vector.
common /laptvplp/ hbz (64)
c---- Index in local array.
common /laptvplp/ n
c---- First index of subset of data.
common /laptvplp/ n1
c---- Last index of subset of data.
common /laptvplp/ n2
c---- Index in external array.
common /laptvplp/ nn
c---- Size of current subset of data.
common /laptvplp/ ns
cbugc***DEBUG begins.
cbug 9901 format (/ 'aptvplp finding projection of A on plane with',
cbug & ' normal B:' /
cbug & (i3,' ax,ay,az=',1p3e22.14 /
cbug & ' bx,by,bz=',1p3e22.14))
cbug write ( 3, 9901) (n, ax(n), ay(n), az(n),
cbug & bx(n), by(n), bz(n), n = 1, np)
cbugc***DEBUG ends.
c.... Initialize.
c---- A very big number.
big = 1.e+99
nerr = 0
c.... Test for input errors.
if (np .le. 0) then
nerr = 1
go to 210
endif
c.... Set up the indices of the first subset of data.
n1 = 1
n2 = min (np, 64)
110 ns = n2 - n1 + 1
c.... Find the unit vector "hb" normal to the plane.
call aptvunb (bx(n1), by(n1), bz(n1), ns, 0.,
& hbx, hby, hbz, blen, nerr)
c.... Find the component of vector "a" perpendicular to the plane.
call aptvdot (ax(n1), ay(n1), az(n1), hbx, hby, hbz, ns, tol,
& ahb, nerr)
c.... Find the components of vector "a" in the plane.
call aptvadd (ax(n1), ay(n1), az(n1), -1., ahb,
& hbx, hby, hbz, ns, tol,
& cx(n1), cy(n1), cz(n1), clen(n1), nerr)
c.... See if vector "b" is too small to define plane.
c---- Loop over subset of data.
do 120 n = 1, ns
nn = n + n1 - 1
if (blen(n) .le. tol) then
clen(nn) = -big
endif
c---- End of loop over subset of data.
120 continue
c.... See if all data subsets are done.
c---- Do another subset of data.
if (n2 .lt. np) then
n1 = n2 + 1
n2 = min (np, n1 + 63)
go to 110
endif
cbugc***DEBUG begins.
cbug 9902 format (/ 'aptvplp results:' /
cbug & (i3,' clen= ',1pe22.14 /
cbug & ' cx,cy,cz=',1p3e22.14))
cbug write ( 3, 9902) (n, clen(n), cx(n), cy(n), cz(n), n = 1, np)
cbugc***DEBUG ends.
210 return
c.... End of subroutine aptvplp. (+1 line.)
end
UCRL-WEB-209832