On 2009-01-16 11:18-0000 Andrew Ross wrote:
> On Fri, Jan 16, 2009 at 12:10:22PM +0100, Arjen Markus wrote:
>>> On Fri, Jan 16, 2009 at 10:40:24AM +0000, Andrew Ross wrote:
>>> To follow up my own post - switching to tcl8.5 gives perfect results, so
>>> this is not a 32-bit issue. Perhaps we should add a note that tcl 8.5
>>> is recommended, although previous versions will work?
>> You should get the same perfect results if you add:
>> set tcl_precision 17
>> to the beginning of the test. This will instruct Tcl 8.4 to do
>> the same as Tcl 8.5 does by default. (Perhaps this should be
>> added to the README or to the examples themselves.)
> We should certainly document that somewhere. If fact, we should probably
> add it into the scripts automatically if the tcl version is < 8.5.
Arjen may well be right that "set tcl_precision 17" will completely fix the
problem for Tcl-8.4, but that needs to be confirmed. Also, there is an
issue of the best place to make that change (i.e., could it be done
centrally or does it have to be done for each example), and once the change
is done, additional cross-platform testing of all examples will be required.
All that is going to take time, and we are only two days away from our
release on Sunday. Arjen, if you can quickly figure out the best
implementation and get a commit done in the next few hours (or by early
Saturday (your time zone) at the latest), then that would give the rest of
us a chance to test your changes before the Sunday release. Otherwise I
think you should wait to deal with this issue post-release, and simply state
in README.release that the Tcl examples give identical results to the C
examples for Tcl-8.5, but there is a precision issue we hope to deal with
before the next release for Tcl-8.4.
Alan W. Irwin
Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).
Programming affiliations with the FreeEOS equation-of-state implementation
for stellar interiors (freeeos.sf.net); PLplot scientific plotting software
package (plplot.org); the libLASi project (unifont.org/lasi); the Loads of
Linux Links project (loll.sf.net); and the Linux Brochure Project