modelica

This is a companion question to External Functions: Reference headers in C-script to compiled dll . That stack overflow question is using a Modelica external function call to a c-script. That c-script then uses c-functions contained within a .dll. Below is the initial preferred method I had attempted and a working attempt that I do not prefer. Initial Attempt: The following code would not work. My assumption was since I loaded the .dll Library libgsl in Modelica I could then simply use headers in the C-script to use function calls from that .dll. However, the dslog.txt file indicated that it

I created an part with the AC library, and when I was trying to simulate the model, there is an error says "Current version of the modelica translator can only handle array of components with fixed size". Not sure what is the meaning of it, and is there anyone has the same issue like this one? Thank you enter image description here Consider the following simple model: model M parameter Integer n(start=3, fixed=false); initial algorithm n := n; end M; It has a parameter n which can be changed before simulation starts. And array dimensions need to be parameter expressions. So you would think

I am integrating a relative small Finite Element (FE) model into Modelica. In doing so, I created a Model (Modelica class) that can read the mass (M) and stiffness (K) matrix in Matlab binary file format. I connected the FE model with some components from the Modelica Standard Library (Modelica.Mechanics.MultiBody). If M and K are very small (say 20x20), then Dymola is able to run the Model and provides pretty accurate results compared to Abaqus (but computational not that efficient). However, if I increase the complexity of the FE model that includes larger M and K (e.g. size(M)=[200,200]),

I have noticed that there are several integration methods available in OpenModelica simulation setup. I dont know what these are. Can I get some sort of information regarding these? Will the quality of results vary if the integration methods are changed? Short document on the integration methods available in OpenModelica: https://openmodelica.org/svn/OpenModelica/trunk/doc/SimulationRuntime/IntegrationAlgorithms/ Yes, the quality (simulation speed, even finding a solution) could vary if you choose different methods. The default is dassl. 来源： https://stackoverflow.com/questions/24257285

Using Dymola 2017. Case A) Calling an external c-script I have had success implementing simple external c functions that have no “# include <-->” statements: Modelica Function: function chirp input Modelica.SIunits.AngularVelocity w_start; input Modelica.SIunits.AngularVelocity w_end; input Real A; input Real M; input Real t; output Real u "output signal"; external "C" u=chirp(w_start,w_end,A,M,t) annotation(IncludeDirectory="modelica://ExternalFuncTest/Resources/Source/", Include="#include \"chirp.c\""); end chirp; C-script: double chirp(double w1, double w2, double A, double M, double time)

I'd like to model a closed hydraulic cycle as one can find in the Modelica Standard Library/Fluid/Examples/HeatingSystem. With the heating system as well as with my (minimalistic) example I've got the same problem: The system is overdetermined. You can find the HeatingSystem as a "bad example" in the following lecture, so I guess this is a well known problem, but I don't really get the point. http://www.modprod.liu.se/MODPROD2011/1.252944/modprod2011-day2-talk3-Keynote-Francesco-Casella-Control-and-Modelica.pdf (page 20) My example is: a pump model producer pipe_flange w,k; parameter Real a,b