subroutine aptlntr (px, py, pz, sx, sy, sz, ax, ay, az,
& bx, by, bz, cx, cy, cz, np, tol,
& dpmin, dint, fracps, qx, qy, qz, ipar, nerr)
ccbeg.
cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
c
c SUBROUTINE APTLNTR
c
c call aptlntr (px, py, pz, sx, sy, sz, ax, ay, az,
c & bx, by, bz, cx, cy, cz, np, tol,
c & dpmin, dint, fracps, qx, qy, qz, ipar, nerr)
c
c Version: aptlntr Updated 1990 May 25 16:20.
c aptlntr Originated 1990 May 25 16:20.
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 point of
c intersection of the line through points p = (px, py, pz)
c and s = (sx, sy, sz), with the plane through the points
c a = (ax, ay, az), b = (bx, by, bz) and c = (cx, cy, cz).
c The point of intersection will be defined by its distance dint
c from point "p", its fractional distance fracps along the line
c from "p" to "s", and its coordinates q = (qx, qy, qz).
c The perpendicular distance dpmin from the plane to point "p"
c is also returned.
c
c If point "p" coincides with point "s", based on tol, the result
c will be the same as if line "ps" is parallel to the plane.
c If points "a", "b" and "c" are colinear or congruent, based on
c tol, the result will be as if line "ps" lies in the plane.
c If line "ps" is parallel to the plane, ipar will be 1. If, in
c addition, dpmin is not zero, dint, fracps, and the coordinates
c of "q" will be very large. If the line is parallel to the plane
c and dpmin is zero, then the line is in the plane, and dint and
c fracps will be zero, and the coordinates of "q" will be
c (px, py, pz).
c
c Flag nerr indicates any input error.
c
c Input: px, py, pz, sx, sy, sz, ax, ay, az, bx, by, bz, cx, cy, cz,
c np, tol.
c
c Output: dpmin, dint, fracps, qx, qy, qz, ipar, nerr.
c
c Calls: aptlnpl, aptvpln
c
c
c Glossary:
c
c ax,ay,az Input The x, y, z coordinates of point "a" in the plane.
c Size np.
c
c bx,by,bz Input The x, y, z coordinates of point "b" in the plane.
c Size np.
c
c cx,cy,cz Input The x, y, z coordinates of point "c" in the plane.
c Size np.
c
c dint Output The distance of the point of intersection "q" from
c point "p". Positive if in the same direction as
c that from "p" to "s". Size np.
c Meaningless if ipar is not zero.
c
c dpmin Output The perpendicular distance to point "p" from the
c plane. Positive if point "p" is in the same
c direction from the plane as the normal vector "vn".
c If less than the estimated error in its calculation,
c dpmin will be truncated to zero. Size np.
c Meaningless if ipar = 2, 3, or 4.
c
c fracps Output Fractional distance of point "q" along the line
c segment from point "p" to point "s". Size np.
c May be negative or greater than 1.
c Meaningless if ipar is not zero.
c
c ipar Output 0 if the line is not parallel to the plane. Size np.
c 1 if it is. See dpmin, dint, fracps, qx, qy, qz.
c 2 if line "ps" is too short, based on tol.
c 3 if triangle "abc" is too small, based on tol.
c 4 if line "ps" is too short, and triangle "abc" is
c too small, based on tol.
c
c nerr Output Indicates an input error, if not 0.
c 1 if np is not positive.
c
c np Input Size of arrays.
c
c px,py,pz Input The x, y, z coordinates of point "p" on the line.
c Must differ from "s", based on tol. Size np.
c
c qx,qy,qz Output The x, y, z coordinates of the point of intersection
c of the line through "p" and "s" with the plane
c through point "a" with normal vector "vn".
c Meaningless if ipar is not zero. Size np.
c
c sx,sy,sz Input The x, y, z coordinates of point "s" on the line.
c Must differ from "p", based on tol. Size np.
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---- Coordinate x of point "a".
dimension ax (1)
c---- Coordinate y of point "a".
dimension ay (1)
c---- Coordinate z of point "a".
dimension az (1)
c---- Coordinate x of point "b".
dimension bx (1)
c---- Coordinate y of point "b".
dimension by (1)
c---- Coordinate z of point "b".
dimension bz (1)
c---- Coordinate x of point "c".
dimension cx (1)
c---- Coordinate y of point "c".
dimension cy (1)
c---- Coordinate z of point "c".
dimension cz (1)
c---- Distance from point "p" to point "q".
dimension dint (1)
c---- Distance from plane to point "p".
dimension dpmin (1)
c---- Fractional distance of "q" along "ps".
dimension fracps (1)
c---- Line is parallel to plane, if 1.
dimension ipar (1)
c---- Coordinate x of point "p".
dimension px (1)
c---- Coordinate y of point "p".
dimension py (1)
c---- Coordinate z of point "p".
dimension pz (1)
c---- Coordinate x of point "q".
dimension qx (1)
c---- Coordinate y of point "q".
dimension qy (1)
c---- Coordinate z of point "q".
dimension qz (1)
c---- Coordinate x of point "s".
dimension sx (1)
c---- Coordinate y of point "s".
dimension sy (1)
c---- Coordinate z of point "s".
dimension sz (1)
c.... Local variables.
c---- First index of subset of data.
common /laptlntr/ n1
c---- Last index of subset of data.
common /laptlntr/ n2
c---- Size of current subset of data.
common /laptlntr/ ns
c---- Magnitude of normal vector "vn"..
common /laptlntr/ vlen (64)
c---- Component x of vector "vn".
common /laptlntr/ vnx (64)
c---- Component y of vector "vn".
common /laptlntr/ vny (64)
c---- Component z of vector "vn".
common /laptlntr/ vnz (64)
cbugc***DEBUG begins.
cbugc---- Index in arrays.
cbug common /laptlntr/ n
cbug 9901 format (/ 'aptlntr finding intersection of the line through:' /
cbug & (i3,' px,py,pz=',1p3e22.14 /
cbug & ' sx,sy,sz=',1p3e22.14 /
cbug & ' with the plane through:' /
cbug & ' ax,ay,az=',1p3e22.14 /
cbug & ' bx,by,bz=',1p3e22.14 /
cbug & ' cx,cy,cz=',1p3e22.14))
cbug write ( 3, 9901) (n, px(n), py(n), pz(n), sx(n), sy(n), sz(n),
cbug & ax(n), ay(n), az(n), bx(n), by(n), bz(n),
cbug & cx(n), cy(n), cz(n), n = 1, np)
cbugc***DEBUG ends.
c.... Initialize.
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 vector "vn" normal to the plane of triangle "abc".
call aptvpln (ax(n1), ay(n1), az(n1), bx(n1), by(n1), bz(n1),
& cx(n1), cy(n1), cz(n1), ns, tol, vnx, vny, vnz,
& vlen, nerr)
c.... Find the distances, point of intersection, etc.
call aptlnpl (px(n1), py(n1), pz(n1), sx(n1), sy(n1), sz(n1),
& ax(n1), ay(n1), az(n1), vnx, vny, vnz, ns, tol,
& dpmin(n1), dint(n1), fracps(n1),
& qx(n1), qy(n1), qz(n1), ipar(n1), nerr)
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 (/ 'aptlntr results:' /
cbug & (i3,' dpmin= ',1pe22.14,' ipar=',i2 /
cbug & ' dint= ',1pe22.14,' fracps=',1pe22.14 /
cbug & ' qx,qy,qz=',1p3e22.14))
cbug write ( 3, 9902) (n, dpmin(n), ipar(n), dint(n), fracps(n),
cbug & qx(n), qy(n), qz(n), n = 1, np)
cbugc***DEBUG ends.
210 return
c.... End of subroutine aptlntr. (+1 line.)
end
UCRL-WEB-209832