Add moment calculation(s) to statistics module

[Peter Peterson]

Add a calculation of the first n-modes to Kernel/Statistics and expose it to python. The function signature should be:

std::vector<double> getMomentsAboutOrigin(const vector<TYPE>& x,
                                const vector<TYPE>& y, const int maxMoment=3);
std::vector<double> getMomentsAboutMean(const vector<TYPE>& x,
                                const vector<TYPE>& y, const int maxMoment=3);

[Peter Peterson]

Re #7672. Added moment calculations to Kernel/Statistics.

The two methods are getMomentsAboutOrigin and getMomentsAboutMean. They work for densities and histograms.

Changeset: 1ff6fd9a126450d3e5f9e36fc9ca5e4f1156b02c

[Peter Peterson]

The function signature was changed because you need to have the x-axis as well. Also there are two types of moments that people might want so just have both.

[Peter Peterson]

This is on ​feature/7672_moment_calc.

To test: since this is really only available from c++, it is probably better to look at the additional unit tests and see if they make sense.

[Russell Taylor]

Test is failing on Windows (sometimes)

[Martyn Gigg]

I ran it in debug and Visual Studio immediately flagged up an out-of-bounds error at Statistics.cpp:364 that must be throwing it off. The fix is obvious as it's the same that is done in the function above so I'll put it in.

[Martyn Gigg]

Fix loop limit that caused out of bounds error on vector access.

Refs #7672

Changeset: a01a48939f3ca754a2546bdf5f5368df99cd9f0c

[Michael Reuter]

The two sets of loops in both functions are nearly identical with the exception of the calculation of temp. The loop max y.size() takes care of both density and histogram cases. Each of the two loops can be consolidated into one.

[Peter Peterson]

Re #7672. Refactored according to Michael's comments.

Changeset: a0636ccee09271bec331241a2e6cfb79fccb10c0

[Peter Peterson]

Assuming that I refactored everything fine (and windoze doesn't break again) the testing should be the same as before.

[Michael Reuter]

Merge remote-tracking branch 'origin/feature/7672_moment_calc'

[Stuart Campbell]

This ticket has been transferred to github issue ​8517