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what is norminal condion

#9727  Permalink Top

what is norminal condion

Feb-19-20 11:19:19

Hello,

I am reading Modelica Code from some Librarys. in the code there is always some norminal values. For example, in a model variable x is declared and the author then declare a parameter x_nom and claim it is the norminal value for x. I am not quite understand the thought behind this. Why should norminal value be defined?

thanks

#9728  Permalink Top

Re: what is norminal condion

Feb-19-20 11:28:50

If you have a variable x that has start-value 0 and is part of a non-linear system, we need to know if x is expected to be a very large or very small value in order for the non-linear system solver to scale better. These are files in the simulation runtime using the attribute:

Code:

$ grep -RI nominal OMCompiler/SimulationRuntime/c | cut -d: -f1 | uniq

OMCompiler/SimulationRuntime/c/optimization/DataManagement/MoveData.c

OMCompiler/SimulationRuntime/c/linearization/linearize.cpp

OMCompiler/SimulationRuntime/c/util/simulation_options.c

OMCompiler/SimulationRuntime/c/simulation_data.h

OMCompiler/SimulationRuntime/c/simulation/simulation_input_xml.c

OMCompiler/SimulationRuntime/c/simulation/solver/nonlinearSolverNewton.c

OMCompiler/SimulationRuntime/c/simulation/solver/linearSolverTotalPivot.c

OMCompiler/SimulationRuntime/c/simulation/solver/nonlinearSystem.c

OMCompiler/SimulationRuntime/c/simulation/solver/dassl.c

OMCompiler/SimulationRuntime/c/simulation/solver/perform_simulation.c.inc

OMCompiler/SimulationRuntime/c/simulation/solver/kinsolSolver.c

OMCompiler/SimulationRuntime/c/simulation/solver/radau.c

OMCompiler/SimulationRuntime/c/simulation/solver/linearSystem.c

OMCompiler/SimulationRuntime/c/simulation/solver/dae_mode.c

OMCompiler/SimulationRuntime/c/simulation/solver/ida_solver.c

OMCompiler/SimulationRuntime/c/simulation/solver/initialization/initialization.c

OMCompiler/SimulationRuntime/c/simulation/solver/perform_qss_simulation.c.inc

OMCompiler/SimulationRuntime/c/simulation/solver/nonlinearSolverHybrd.c

OMCompiler/SimulationRuntime/c/simulation/solver/nonlinearSolverHomotopy.c

OMCompiler/SimulationRuntime/c/openmodelica_func.h

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