Ticket #2606 (closed: fixed)
Plotting negative values incorrectly when Log scale set in preferences
| Reported by: | Nick Draper | Owned by: | Steve Williams |
|---|---|---|---|
| Priority: | major | Milestone: | Iteration 28 |
| Component: | MantidPlot | Keywords: | |
| Cc: | ann.terry@… | Blocked By: | |
| Blocking: | Tester: | Anders Markvardsen |
Description
From Nick:
It only occurs when you set your preferences of the a scale to log in the preferences window and then do a plot with a negative number on that scale. In this case the negative number is translated to a very high number in the plot.
If you leave the preferences for Y axis as linear, and then manually change them to Log by right clicking the plot and selecting axes->log, log Then this works fine and the negative values are ignored rather than be plotted arbitrarily high.
I understand this is not ideal at the moment and we will change it such that negative values are ignored throughout
From Ann Terry and Stephen King:
It occurs when Mantid plots the 2D data on a graph where the default axes set in Preferences are log-log. If they are set to lin-lin the plot is fine.
Screen shot and output workspace in babylon5/loq.
Change History
comment:2 Changed 10 years ago by Steve Williams
- Status changed from new to accepted
The following workspace is a test case, plotting it when your view->preferences->2D Plots->Axes->DefaultY is set to log gives you the spurious 1020.
CreateWorkspace(OutputWorkspace="first_postive",DataX="1,2,3,5,6,7,8",DataY="1,-1,3,5,4,5",DataE="1,1,3,5,4,5",UnitX="TOF",VerticalAxisUnit="TOF",VerticalAxisValues="2")
comment:6 Changed 9 years ago by Steve Williams
- Status changed from accepted to verify
- Resolution set to fixed
comment:7 Changed 9 years ago by Anders Markvardsen
- Status changed from verify to verifying
- Tester set to Anders Markvardsen
comment:8 Changed 9 years ago by Anders Markvardsen
- Status changed from verifying to closed
Now when using the script
CreateWorkspace(OutputWorkspace="first_postive",DataX="1,2,3,5,6,7,8",DataY="1,-1,3,5,4,5",DataE="1,1,3,5,4,5",UnitX="TOF",VerticalAxisUnit="TOF",VerticalAxisValues="2")
and log set in preference negative data points not plotted.
(By the way trac does not seem react properly this morning...., this is the 3rd time I try and pass ticket...)
From Richard Heenan:
Note that having got the 1e20 numbers on a log axis, they stay there on changing the axes back to linear and do not revert to their proper (negative) values.