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<DIV><SPAN class=156322015-06012005><FONT size=2>I have encountered a problem
when trying to use the \fp package within multido and pst-3dplot, that I cannot
figure out. Specifically the problem arises when I try to use an \fp test
(\FPifpos...).</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2>I am trying to produce an
accurate pspicture of an elliptic orbit, going around the earth. In this
case, the orbit is "centered" with one of its foci (and not the ellipse center)
at the center of the earth. In my first solution (rather brute force and
dumb ignorance) I used the fp routines to repeatedly determine points on the
orbit path in 1 degree steps. I the used the new pstRotPoint routine
written by Herbert Voss to rotate everything into inertial space (a total of
three rotations for each point). After some initial difficulty (mostly my
own typing problems) I produced a satisfactory picture. However, as some
portions of the orbit lie above the equatorial plane and some below, I wished to
use two different line styles or colors to distinguish them (a bit of a hidden
line thing).</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2>As soon as I include an
\FPifpos ...\else ...\fi set of statements I produce a "compiler" error that I
cannot find. (see below). I can step or "scroll" through the errors (and
if I cut back the number of points to less than 100) can produce the picture I
want. However, I need 360 points to produce a complete and "smooth"
curve. At this point the compilation fails.</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2>Attached are the following
files</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2>1) the .tex file for the
example, with the "offending" fp routines commented out</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005><FONT size=2>2) a .pdf file produced
"without" the offending fp calls.</FONT></SPAN></DIV>
<DIV><SPAN class=156322015-06012005></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005>Note that because of the very large number
of fp calls this file takes a few moments to compile. You will need the
latest version of pst-3dplot in order to compile properly.</SPAN></DIV>
<DIV><SPAN class=156322015-06012005></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005>Subsequently I have found a much more
elegant way in which to solve the original problem (i.e. draw a picture of a
proper orbit) but would like to know what is wrong.</SPAN></DIV>
<DIV><SPAN class=156322015-06012005></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005>Thanks</SPAN></DIV>
<DIV><SPAN class=156322015-06012005></SPAN> </DIV>
<DIV><SPAN class=156322015-06012005>Bruce
Burlton<BR></SPAN></DIV></FONT></DIV></BODY></HTML>