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visit-dav / visit

VisIt - Visualization and Data Analysis for Mesh-based Scientific Data
https://visit.llnl.gov
BSD 3-Clause "New" or "Revised" License
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More issues with coordinate transformations with Transform operator #17190

Open markcmiller86 opened 2 years ago

markcmiller86 commented 2 years ago

This report involves both the original ucd3d.silo file and the modified one attached in in #17189 where the x/y values are replaced with r/theta, all else being identical. In particlar, these lines in testtall.C, https://github.com/visit-dav/visit/blob/48af304262c8c0b2b329c1da175473e7ca6e1243/src/tools/data/datagen/testall.C#L2282-L2283 are modified to 

2282      Xv = r;
2283      Yv = theta;

This means that the mesh's coordinates are specified in cylindrical rather than cartesian system.

  1. Apply a cartesian-to-cylindrical coordinate Transform operator to the original mesh. You get something bizarre... Screen Shot 2021-12-10 at 3 41 20 PM Why? Isn't this doing the same thing that the above source code line changes do? Also, when I do a spatial extents query on the result, I get The actual extents are (2, 5, -3.14159, 9.2677, 0, 10) which is a bit odd in that the angle starts at -pi and the z is half the range it should be.
  2. Compare PC plots of 'd' variables in both the cylindrical (left) and original cases. You get a different d variable... Screen Shot 2021-12-10 at 3 45 52 PM There appears to be some off by one error.
  3. Compare PC plot of 'd' variable from cylindrical database with no transformation and with two coordinate Transform operators applied (cylincrical->cartesian followed by cartesian->cylindrical)...the bounding box is strange... Screen Shot 2021-12-10 at 3 49 47 PM Shouldn't these two be identical?
markcmiller86 commented 2 years ago

Ok, item 2, above is actually a bug I introduced in data generation for cylindrical case. I am fixing that now and will re-upload the data file to #17189