[BugFix] BeamDyn nodal outputs occasionally segfaulted #996
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The cause was an index that never got set. So this could result in attempting to retrieve a value from the output mapping array using an out of bounds index (sometimes a very large negative number). This never appeared in gcc compiled versions, but occasionally would appear in certain intel compiled versions (others initialized the value apparently).
jjonkman
approved these changes
Feb 10, 2022
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Feature or improvement description
BeamDyn would occasionally incur a segmentation fault when nodal outputs were requested. This appeared to happen only with certain Intel compiler version on Windows and was difficult to reproduce reliably. The root cause was the first entry in
NdIndxInverseindex lookup table not getting set (this index table is used to map the quadrature point node to the correct nodal output channel). Thus the first index value would be whatever was resident in that memory location and might be a value outside the range of the output nodes which would result in a segmentation fault.For whatever reason, I could only reproduce this error with some Intel compiles on Windows. It did not show up on Linux or with the gcc compilers. Maybe this is due to different memory layout or previous stored values in the particular memory space (hard to tell without spending more time on the issue).
This issue only affected the indexing for the first node, so may in some instances have caused incorrect outputs for the first node nodal outputs to not match the root outputs.
Related issue, if one exists
Maybe related: #248
Noted in forum post: https://forums.nrel.gov/t/sending-rtaeropwr-via-servodyn-to-bladed-style-dll-controller/2043/14
Impacted areas of the software
BeamDyn node based outputs are the only bit of code affected.