Revert primal dual test to meaningful result

[mmcleod89]

• Brings primal dual test into line with others (checks the MSE rather than a strict regression test)
• Reverts previous changes made to measurement operator
• Now produces a reasonable looking image

The commit message attached to the code that had to be changed back was: "updated unit tests to be shorted and use un normed operators", which suggests that the un-normalised operators may be an issue for the implementation of the PD algorithm? (Commit 40be6b8)

[mmcleod89]

Original primal dual solution (solution.jpg) and current primal dual solution (pd_result.jpg) for context. I don't get exactly the same result but it looks very close.

[tkoskela]

It looks like the test still fails. Are we supposed to be multiplying average_intensity by 1e-3 in

purify/cpp/tests/algo_factory.cc

Line 130 in d8c9152

CHECK(mse <= average_intensity * 1e-3);

Is this a unit conversion?

[mmcleod89]

Not a unit conversion, just an loose attempt to check that the average error per pixel was significantly less than the average value per pixel as a first attempt at checking for similarity of solutions.

[mmcleod89]

I will play around a bit more with these tests and the UQ tomorrow

[mmcleod89]

These tests should pass when SOPT is updated to account for the change in the initial guess for PD