Changes between Version 1 and Version 2 of Ticket #702, comment 1
- Timestamp:
- Jun 30, 2017 11:29:07 AM (7 years ago)
Legend:
- Unmodified
- Added
- Removed
- Modified
-
Ticket #702, comment 1
v1 v2 1 1 More practically, the cylinder model does not support carbon nanotubes, with length 10 um and diameter 1 nm. 2 2 3 Calculations for different numbers of integration steps attached. Simulations were run with explore/symint.py in the ticket-776-orientation branch, along with the I(q, theta) function that is being integrated for a few different q points.3 Calculations for different numbers of integration steps attached. First image shows the highly oscillatory function that we are integrating at several q points. The second image shows the results for a few different optimization strategies. Trapezoidal method for 65000 points and 525000 points are indistinguishable on the graph, and so that is likely the true value. 4 4 5 The current code supports lengths up to 0.1 um. Switching to a 150 point gaussian will allow up to 1-2 um. A 1000 point gaussian will brings the error down to 1.5% for the 10 um length. The GPU may prefer 1024. 5 Repeating the tests with different lengths, it seems that the current code with the 76 point Gaussian integration supports lengths up to 0.1 um. Switching to a 150 point Gaussian will allow up to 1-2 um. Using Gaussian integration with 1024 points (not shown) gives results within 1.5% of the 525000 point trapz. [1024 is a nicer number for GPUs to work with, though any multiple of 4 ought to be fine.] 6 7 Simulations were run with explore/symint.py in the ticket-776-orientation branch. 8 9 [[Image(I-q-theta.png, 700px)]] 10 [[Image(I-q-integrated.png, 700px)]]
