neutrons / multiphonon

multiphonon (getDOS)
MIT License
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Negative value in A1(E=0) #38

Closed yxqd closed 7 years ago

yxqd commented 7 years ago

We were using crude interpolation to determine A1(E) at E=0 (https://github.com/sns-chops/multiphonon/blob/e6ed8b84aa165c6a17a95c6f3d3678d45d7e5df8/multiphonon/forward/phonon.py#L182). It may leads to negative value. Here is an example a1e

A1(E=0) is not critical to the later calculation since it is just one point, and A2+(E) are convolutions of A1(E). However, negative value is too strange. Should force non-negative.