Integration accuracy without contacts about consim HOT 7 CLOSED

yes I know why this issue appears, it is just that exponential solver still has pinocchio::aba() for integrating in the air here compare pinocchio::ComputeMInverse() here

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Maybe @jcarpent could help us with this. We are computing the forward dynamics with 3 different methods here. They should all give the same results, but they don't. For instance:

When I do the same in Python I get the same results, so clearly there's something wrong with the way we are using these methods in C++. Any idea what could be the problem?

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Thanks to the PR of @jcarpent now the Euler simulator gives consistent results when the robot is in the air. However, this is not the case for the ExponentialSimulator. Here some results:

Basically it seems that everything works except for Exp-Cholesky. But Cholesky works fine in the Euler simulator.

Moreover, what's really weird is that if I replace this line in the code with this:

dvMean_.noalias() = data_->Minv*mDv_; 

(as it was done in the PR by @jcarpent ) and recompile, then I get different results also for Exp-ABA, which shouldn't be affected by this change:

The line corresponding to Exp-ABA is a bit hard to spot, but it's basically overlapping with the one of Exp-Cholesky.

The only possible explanation I have for this is some memory issues. Any other idea?

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hi @andreadelprete ,
there was a minor bug here that i fixed, could you confirm that his fixes the issue you see with Exp-Cholesky ?

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I confirm that this solves the problem. However, I am still worried about the result I reported above, because I am afraid there might be some issues with the memory. I don't know how to proceed to try and find them though.

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Could we do a meeting to explain me in details the issue you have in mind?

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Let's close this issue for now

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