More effective

[FreeBirdLjj]

More effective by following changes:

• Add const to some parameters
• Add shared() section to OpenMP pragma
• Move some calculations into inner loop so some temp array can be replaced by temp elements.

[myint]

Cool, thanks.

I've merged everything except a few of the unnecessary const parameters in the headers. (I completely agree that const parameters in the function implementation is very useful. But in the declaration I think it is unnecessary and possibly noisy to the reader.)