| 8:28:25 AM PDT - Wed, Apr 9th 2014 |
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Hi Ylniu,
The coefficients you are showing that vary in value are really small (of the order of 1.0e-14). The machine precision is only around 1,0e-15. Therefore the variations you are looking at are the result of the finite precision of the computer. The third coefficient is much larger (around 0.4) and you see that all digits are the same. So no, NWChem does not use a random number generator, but some numbers get so small that not all digits are significant to the overall result. The insignificant digits can essentially take any value. This is just a consequence of the finite precision of digital machines and basic numerical error analysis.
I hope that helps,
Huub
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