Hi,

Eclipse's (Mars) CDT indexer does not parse Eigen 3 properly. I am trying to understand why that is the case, the indexer works well for every other library I've used. Moreover I have the same issue with Vim's YouCompleteMe plugin, the indexer is unable to resolve anything related to Eigen 3. I have read the suggestions related to IDEs in the FAQ ([here][http://eigen.tuxfamily.org/index.php?title=IDEs]), but the problem still pertains. The project compiles correctly, the include paths are set up as indicated in the link. Both YouCompleteMe and Eclipse CDT recognize the include path (e.g. <Eigen/Sparse>) correctly, it is the namespaces (Eigen::), classes and methods that are not recognized to belong to the included file (eg. Sparse). Is anyone aware of a workaround?

Apologies if this forum is not the right place to post this question, but since I have the issue with multiple plugins/IDEs, I am more inclined to think it is not a plugin/IDE specific issue. That being said, I am not sure at all what the problem might be. My only guess is that it might be due to the way Eigen groups include statements into files with no .h extension. However, the C++ standard library does that as well so... The issue seems to be relatively old and quite a few people have it, I was not able to find a suggestion that works for me.

On a side note, would anyone be able to clarify why the design choice of grouping include statements into files with no .h extension combined with avoiding to explicitly declare include statements in .h files was made? Is there a benefit in the speed of compilation or there other reasons?

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I managed to get it working using an eclipse project file generator (.project and .cproject) for cmake, i.e. (cmake -G "Eclipse CDT4 - Unix Makefiles"). I do not know why it works though. The include paths are exactly the same as the one I specified manually. I use the same include paths in Vim' YCM plugin configuration file as well, it still doesn't work there.