Implement Fullprof's polynomial background

[Wenduo Zhou]

Implement the polynomial background (Nba=0) defined in Fullprof.

[Wenduo Zhou]

Starting to implement (not finished). Refs #8109.

Changeset: e9fb8043daed7f0d1b2b52bb48a406f11b3e1b8c

[Wenduo Zhou]

Updated CMake. Refs #8109.

Changeset: 93a44423ee08b817abbb326570beb77bb416324c

[Wenduo Zhou]

Made progress in implementation. Refs #8109.

Changeset: 9d2449b7e77e355e903498a857429b369fbd1130

[Wenduo Zhou]

Fixed a bug and started implementing unit test. Refs #8109.

Changeset: 515a122bd3f8c67cd2843678b711d92a829fa3f5

[Wenduo Zhou]

Added unit test. Refs #8109.

Changeset: e36640c933a8aea756e854a9efb14b89a64c281d

[Wenduo Zhou]

For Testers

The math of this background function can be found at http://www.mantidproject.org/PolynomialBackground.

Here is a simple way to see how the function works:

1. Download attached data file. The data is from a Fullprof .prf file of a VULCAN Silicon run. The polynomial coefficients (listed below) are from the .pcr file.
2. In MantidPlot, run 'LoadAscii' to load this data file.
3. Launch fit interface on the loaded workspace;
4. Add the background function 'FullprofPolynomial';
5. Set the function as
   • n = 6
   • Bkpos = 11000.
   • A0 ~ A5 as 0.034, 0.027, -0.129, 0.161, -0.083, 0.015
6. Evaluate the function. You can see how close the Fullprof result and Mantid result are.
7. Fit the function. You should get a even better match while the refined coefficients should not have huge different from the input.

[Vickie Lynch]

Merge remote branch 'origin/feature/8109_new_fp_bkgd'

Full changeset: ​497e64d1da087163c0bbcc29fd70ac75a9a362eb

[Stuart Campbell]

This ticket has been transferred to github issue ​8954