I am continuing to work with the fortran examples to make them as consistent
as possible with the C examples as a test of the fortran interface
* The first 5 fortran examples now give identical postscript file results to
the corresponding C examples.
* I believe there is nothing more I can do with the 6th and 7th examples to
make them consistent with the C equivalents. AFAIK, the arguments that get
passed to the C library in both cases should be identical within the
floating-point uncertainties of roughly 1 part in 10^16. Indeed, the
fortran and C versions give near identical visual results, but at 10x
magnification you can see some of the letter strokes changing slightly
between fortran and C. Also, diff shows lots of small differences between
the postscript files. I believe these differences are due to rounding
errors propagating by chance from our double-precision arguments through the
low-resolution (16-bit) rendering for all file devices and eventually to the
postscript rounding. I believe the propagation of rounding errors will be
much reduced when we have the option of using 32-bit (or even 64-bit)
rendering, but that is a low priority item at the moment.
Meanwhile, a much higher priority is to continue with the fortran example
consistency work; next on my list (possibly tomorrow) is implementing the
fortran API for plsurf3d and testing it with example 8.
My best wishes to the PLplot developers during this Christmas season.
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the PLplot scientific plotting software
package (plplot.org), the Yorick front-end to PLplot (yplot.sf.net), the
Loads of Linux Links project (loll.sf.net), and the Linux Brochure Project