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As for tcl/tk 8.4, the plan is that we build python against the same version used by the ftools (sometimes referred to as heasoft). We have a copy of heasoft installed at SLAC, currently on a rh9 build..but I'll be doing a rhel4 build soon. That build is located at $GLASTROOT/applications/heasoft/
Versions installed:
numpy 1.2.0
pyfits 1.3
4SuiteXML 1.0.2
Installing Python 2.5.1 (built against tcltk 8.4) for Linux
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