Opened 4 years ago

Closed 2 years ago

Last modified 2 years ago

#288 closed defect (fixed)

Problem with multishell model - glitches at high Q

Reported by: ajj Owned by: ajj
Priority: critical Milestone: SasView 4.1.0
Component: SasView Keywords:
Cc: Work Package: SasView Bug Fixing

Description

The multishell model has artifacts that appear when the dimension of the core is greater than some value (depends on Q range whether the artefacts are within the range).

Same problem appears in IGOR, so it is an underlying model issue. Suspect a problem with either integration or bessel function precision.

This needs fixing ASAP

Change History (7)

comment:1 Changed 4 years ago by butler

  • Milestone changed from SasView 3.1 to SasView Next Release +1

This probably is best worked through as part of new sasmodels. Since has existed in IGOR code for a while already and will require probably a fair amount of sleuthing that we may not have the bandwidth for we won't hold up the release 3.1 to fix this

comment:2 Changed 3 years ago by butler

  • Milestone changed from SasView Next Release +1 to SasView 4.0.0

comment:3 Changed 3 years ago by ajj

  • Priority changed from major to critical

comment:4 Changed 2 years ago by butler

  • Milestone changed from SasView 4.0.0 to SasView Next Release +1

once again running out of bandwidth to check this for the upcoming release 4.0 — moving to next release

comment:5 Changed 2 years ago by pkienzle

This ticket needs specific parameter values to check against, as well as a description of the artefacts. Many of the models have been updated to use more accurate bessel function approximations, at least for small qr, so this may already have been fixed.

comment:6 Changed 2 years ago by richardh

  • Resolution set to fixed
  • Status changed from new to closed
  • Summary changed from Problem with multishell model to Problem with multishell model - glitches at high Q

Symptom - regular glitches in I(Q) at high Q when using polydispersity in any core shell model.

FIX - users should increase number of steps NPTS and/or number of sigmas NSIGS to integrate over, in the polydispersity integral

comment:7 Changed 2 years ago by butler

  • Milestone changed from SasView Next Release +1 to SasView 4.1.0
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