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Constraint Type: Lagrange multiplier Vs Penalty Function

Posted: 01 Jun 2026, 06:29
by sarif
Dear Support Team,

I have noticed that using Lagrange multipliers slows the analysis down significantly. The analysis time is many times longer than the penalty function. Are there significant differences in the analysis results while using the two types of constraints?

Re: Constraint Type: Lagrange multiplier Vs Penalty Function

Posted: 01 Jun 2026, 11:30
by seismosoft
Depending on the number of constraints that you have, the Lagrange multipliers increase the number of equations for the matrix calculations. Another issue that might cause the delay is the zero diagonal values introduced in the stiffness matrix that might cause numerical instabilities.
Seismosoft Support

Re: Constraint Type: Lagrange multiplier Vs Penalty Function

Posted: 02 Jun 2026, 04:30
by sarif
Okay. Thank you