How can I delete "almost"-zeros in expressions?

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Squier255

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Feb 15, 2019, 9:01:35 AM2/15/19

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Hi,

I use Matlab with Casadi 3.4.5 in combination with the IPOPT Interface. I noticed that I have a Jacobian matrix that contains values like "1e-12" which makes the jacobian less sparse and therefore the computation time less efficient.

My question is: Can I and if so how do I delete these entries? Or does IPOPT "ignore" them anyway somehow.

Thank you guys in advance.

Simon

Squier255

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Feb 25, 2019, 11:12:43 AM2/25/19

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Does nobody know?

Joel Andersson

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Feb 25, 2019, 1:44:54 PM2/25/19

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Nonzeros in the Jacobians are fixed at construction and does not depend on particular numerical values. If you want to avoid the small entries, you need to reformulate your problem accordingly. How IPOPT handles small entries is a question for the IPOPT mailing list. My guess is that it depends on the linear solver used.