modelica

问题 Is there a way to change the value of "Maximum number of event iterations" , eviter , that is set to 20 in dymola? 回答1: It seems like dymosim.ini is not used for regular simulations (Note the version in line 4: dymosim.ini states 1.1, whereas the dsin.txt has 1.4 written in Dymola 2019). I also could not find a function or variable in Dymola to change eviter , so the only solution I can think of is to edit dsin.txt before simulation. The code below shows how a function could look like which

问题 Motivation Modelica does store units of measurement (e.g. SI units and Non-SI units) as an attribute with regard to a variable. Here is an example for a Non-SI-unit: type Time_months = Real( quantity = "Time", unit = "mo", displayUnit = "months" ) Since for models in economics it will be rather akward to give rates in seconds, I would like to write a rather general unit conversion function that will allow to convert units of time. So ideally a function to convert to another time base should

问题 I want to do local senstivity analysis in Dymola to evaluate different parameters affecting the energy consumption in a building (for multi-familyhouse). Can anyone give me some suggestions, how to do it in Dymola (Modelica) software? 回答1: You could export you model as FMU and then follow one of many the different paths for sensitivity analysis with FMUs: PyFMI + SAlib Sensitivity Analysis using PyFMI - FMU in for-loop FMI Toolbox for Excel by Modelon http://www.modelon.com/products/modelon

问题 I am making simulations for long times and I need to check the output when the simulation is continuing. Another reason is that I am doing real-time simulation so I want to see the output in real-time as well. That would be perfect if OpenModelica creates an output file during the simulation so that I can read and plot it using 3rd party tools, maybe Python. So far as I know, OpenModelica creates output file only at the end of the simulation. Is there a way to create an output file using a

问题 Following this question, I modified my code to: model test // types type Mass = Real(unit = "Kg", min = 0); type Length = Real(unit = "m"); type Area = Real(unit = "m2", min = 0); type Force = Real(unit = "Kg.m/s2"); type Pressure = Real(unit = "Kg/m/s2"); type Torque = Real(unit = "Kg.m2/s2"); type Velocity = Real(unit = "m/s"); type Time = Real(unit = "s"); // constants constant Real pi = 2 * Modelica.Math.asin(1.0); parameter Mass Mp = 0.01; parameter Length r1 = 0.010; parameter Length r3

问题 Example: You create a model with 9 parameters you expect to be editable in the Simulation tab and user-settable in the FMU. However, Only 5 parameters appear to be editable from the Simulation tab. Likewise, FMU has only 5 user-settable parameters. 回答1: Solution: To generate more efficient code, Dymola sometimes "evaluates" parameters. annotation(Evaluate=false) tells Dymola a parameter should not be evaluated. Example: parameter Real theAnswer = 42.0 "The answer to life,…" annotation

问题 Assume I have a large connector involving all kinds of base types (Real, Integer, String, Boolean). How can I switch connections based on state events? I would like to do something like this: model switch input ComplicatedConnector icon[2]; output ComplicatedConnector ocon; input Real x; equation if x >= 0 then connect(ocon, icon[1]); else connect(ocon, icon[2]); end if; end switch; This does not work. How can it be properly expressed in Modelica? Answer based on comment by Adrian Pop. model

问题 I would like to perform integration of a function of a variable other than time in Modelica, but I don't know how to do it. For example, how can I evaluate the integral of x dx with upper limit 5 and lower limit 2? ∫x dx=x^2/2 回答1: Modelica was not designed to be a CAS (computer algebra system) as Maple, Mathematica or Matlab, but with a little coding you can do it anyway. The thing is that your problem can not be solved automatically symbolically with Modelica tools, but numerically yes. In

问题 In Modelica it is possible to define external functions. Chapter 12.9 of the spec says C and Fortran77 are supported, C++ and Fortran90 might be supported in the future. Now I wonder which versions of C are supported? In particular I need the logarithmic gamma function which is available in C99, so I tried the following: function lgamma "logarithmic gamma function" input Real u; output Real y; external "C" y = lgamma(u); end lgamma; but it does not work, while powf works: function powf "power

问题 I'm trying to let a parameter be of a specific type depending on a condition to be met. But I'm not quite sure how to do this or if this is actually possible/legal in Modelica. In principle what I would like to have is something like this (non-working code example): package test type TypeA=enumeration(A,C,E); type TypeB=enumeration(B,D,F); model foo parameter Boolean Condition; parameter if Condition then TypeA else TypeB MyParameter; end foo; end test; 回答1: I was hoping to acheive this with