Resolution calculator gives incorrect results for sigma x, sigma y (Trac #1244)

[pkienzle]

SasView 4.2.1

Select menu >Tools >Q resolution estimator

Set Qx=0.005, Qy=0.03 and click "Compute"

Resolution is clearly elliptical but Sigma_x and Sigma_y are identical.

Hammouda's online [https://www.ncnr.nist.gov/staff/hammouda/distance_learning/chapter_15.pdf SANS course] (ch 15, pg 9) has formulas for sigma x and sigma y.

Migrated from http://trac.sasview.org/ticket/1244

{
    "status": "new",
    "changetime": "2019-03-12T22:47:10",
    "_ts": "2019-03-12 22:47:10.718454+00:00",
    "description": "SasView 4.2.1\n\nSelect menu >Tools >Q resolution estimator\n\nSet `Qx=0.005`, `Qy=0.03` and click \"Compute\"\n\nResolution is clearly elliptical but `Sigma_x` and `Sigma_y` are identical.\n\nHammouda's online [https://www.ncnr.nist.gov/staff/hammouda/distance_learning/chapter_15.pdf SANS course] (ch 15, pg 9) has formulas for sigma x and sigma y.\n",
    "reporter": "pkienzle",
    "cc": "",
    "resolution": "",
    "workpackage": "SasView Bug Fixing",
    "time": "2019-03-12T22:47:10",
    "component": "SasView",
    "summary": "Resolution calculator gives incorrect results for sigma x, sigma y",
    "priority": "major",
    "keywords": "",
    "milestone": "SasView 4.3.0",
    "owner": "",
    "type": "defect"
}

[butlerpd]

Actually I believe this is correct. Regardless, I think it is clear we should not be spending resources to fix in 4.x so am going to move this 5.1.

I would have to look at this again but believe there was a long discussion about 2D resolutions and in particular the fact that given them in x and y rather than radial and perpendicular was very problematic as the wavelength distribution only smears along the radial direction not the transverse one.... all of which opens up a whole new can of worms :-)