subroutine IRPL_GREATXSMALL Purpose intersections between a great circle and a small circle File irpl_greatxsmall.shl Class IRAS, Math Author 850712 Uwe Peppel Use subroutine IRPL_GREATXSMALL( polegc, I doubleprecision(3) theta, I real pint, O real(3,2) nrint ) O integer polegc coordinates of one pole of the great circle theta polar angle of the small circle (in rad) pint intersection points nrint number of intersection points found Description The input parameters have to be given in a rectangular coordinate system with the z-axis pointing to the center of the small circle. The great circle has to be specified by the coordinates of one of its poles, the small circle by its polar angle. If intersection points are found, they are given by the array PINT. nrint can be 0, 1, or 2. nrint =1 means that the two circles have one common point. For the trivial case of THETA = 90 and POLEGC = (0,0,1) where the two circles are identical, nrint is given the value -1. Update 900911 DK, all real variables to doubleprecision