Fix exported workspaces in ALC

[raquelalvarezbanos]

Reported by James Lord and Jamie Peck:

In the exported Baseline workspace, there are three histograms corresponding to the three histograms created after a normal fit ("Data", "Calc" and "Diff", called "Data", "Baseline" and "Corrected" in this interface). The "Data" histogram has its original errors (OK), the "Baseline" histogram seems to have HUGE error bars (Bad) and the "Corrected" data has errors=0 (Bad). The same happens in the PeakFitting step when exporting fitting results.

This is caused by two different issues:

1. When exporting fitting results, the interface does not use the output workspace created by the Fit algorithm. Instead, it is doing the following:

• It creates a Fit algorithm and stores "Data", "Diff" and the fitted function in separate member variables.

• When exporting, it takes both "Data" and "Diff", and populates the "Calc" histogram by creating a new "Fit" algorithm with 0 iterations (which takes the previously fitted function). This is causing the "Baseline" (or equivalently "Calc") data to have huge errors. The interface SHOULD export the three spectra resulting from the first "Fit" algorithm.

  This is a bug in the ALC interface and will be solved here.

1. The fit algorithm does not seem to compute errors for the "Diff" data, and therefore it causes the "Corrected" data in the interface to have zero errors.

   This is related to the Fit algorithm and is not going to be solved here, I will create a new ticket for it.

   Keywords: Muon, ALC

[raquelalvarezbanos]

This issue was originally trac ticket 11711