id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,workpackage 835,Fractal model not useable with dQ data due to being undefined for negative q,smk78,pkienzle,"Reported by Rafal Kryszton and verified by smk78. Affects Mac & Win. The Fractal model in 4.1 builds and the 4.0.1 release is exhibiting unusual behaviour, not present in the 3.1.2 release, when dQ smearing is enabled. An error is thrown: Plotting Error: Data has no positive values, and therefore cannot be log-scaled. Depending on the root cause, this issue may affect other models. To demonstrate: Load the attached data. Send to Fitting. Select the Fractal model. Unselect all parameters. With Instrumental Smearing = None, set fractal_dim to a number other than 2 and hit Enter. The model should recompute. Now set Instrumental Smearing = Use dQ data and repeat. If fractal_dim is any value other than 2 the error is thrown and the model is not recomputed or disappears from view. Reselecting Instrumental Smearing = None redisplays the model line. Side Comment: The .txt file is the users original data file. This reads into 4.1/4.0.1 BUT NOT into 3.1.2. The .csv version reads into all. ",defect,closed,blocker,SasView 4.1.0,SasView,fixed,,,SasView Bug Fixing