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<p><font size="-1">Dear Zhao <br>
</font></p>
<p><font size="-1">The mixing of PAW files is not implemented in
virtual. Most likely what is happening is that the file you
produced with virtual_v2.x is declared as a PAW in the header,
but as some PAW dataset is missing in the new UPF file, the
program goes in error when it tries to read them. <br>
</font></p>
<p><font size="-1">By the test that I have done virtual_v2.x produce
valid files for norm conserving and ultrasofts, but results are
reliable only in the norm conserving case. So I would stick to
norm conserving. <br>
</font></p>
<p><font size="-1">greetings - Pietro </font><br>
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