[Wien] accuracy problems

[Sorin Lazar]

Hi everyone,

We are seeing some accuracy trouble with Wien2k when combining various 
compilers and blas+lapack libraries on PowerMac systems.
The data from the TiC sample case is as follows:

    compiler      library                                        result
1) Absoft         Absoft                                        correct
2) Absoft         vecLib                                        incorrect
3) xlf               veclib                                         incorrect
4) xlf               manually compiled blas/lapack     incorrect

The incorrect results are pretty similar for the three wrong cases. From 
1-3 the vecLib libraries would seem the culprit. But 4 kills that logic. 
 From this data, it seems that it is not just the compiler or just the 
library. 2+3 tells you it is not just the compiler that is giving the 
error. 3+4 tells you the library is not the sole culprit.
Someone who was helpful in finding out the above data suggested that it 
could be some numerical instability issue in the Wien2k code. The code runs 
fine of course on many platforms, including PowerMacs using all-Absoft. Has 
anyone ever seen something similar, perhaps using development-stage 
versions of the code?

kind regards,
Sorin Lazar, Peter Klaver
PhD student Delft University
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