Fix incorrect parsing of FCIDUMP with complex-valued integrals

[bkesk]

The FCIDUMP format with complex-valued integrals should have format:

  V_real V_imag a b c d

and

boost::split(tok, msg, is_any_of(", \t()"), token_compress_on);

should split each line into 6 tokens, not 7, unless some unexpected whitespace character is included before V_real.

[xubwa]

I used (V_real, V_imag) a b c d in complex FCIDUMP. I'm not aware of a standard definition of complex valued FCIDUMP, it should just be a arbitrary choice. Dice's complex valued relativistic integral is generated from PySCF and BAGEL which both used the format I described.

[bkesk]

Thanks for the quick response. I suppose you're right. The general FCIDUMP format doesn't specify how to handle complex-valued integrals, it's just X a b c d where X can be real or complex. Let me see what happens when I use the format that you specified here.