如何消除 Dymola/Modelica 中的死代码

Question

我正在尝试精简一个非常复杂的模型以提高性能，并注意到当我在信号总线中添加或删除变量时，特别是多体框架的巨大性能变化。

我想知道是否有任何设置可以消除不参与从模型生成输出的代码。

我尝试将总线连接器设置为“受保护”以确保它不会成为输出，但仍在生成计算它们的代码。

我也尝试过这些标志，但它并没有消除死代码：

Advanced.Embedded.OptimizeForOutputs=true;
Advanced.SubstituteVariablesUsedOnce=true;
Evaluate=true;
Advanced.EvaluateAlsoTop=true;
Advanced.SubstituteVariablesUsedOnce=true;

这是一个简单的模型来复制场景：

model TestBusConnector
  extends Modelica.Icons.Example;
protected 
        Modelica.Blocks.Examples.BusUsage_Utilities.Interfaces.ControlBus controlBus
    annotation (Placement(transformation(extent={{-20,-20},{20,20}})));
public 
  Modelica.Blocks.Sources.Sine sine(freqHz=1)
    annotation (Placement(transformation(extent={{-40,-50},{-20,-30}})));
  Modelica.Blocks.Sources.Constant const(k=0)
    annotation (Placement(transformation(extent={{-10,50},{10,70}})));
  Modelica.Blocks.Interfaces.RealOutput y
    annotation (Placement(transformation(extent={{90,-10},{110,10}})));
equation 
  connect(y, const.y) annotation (Line(points={{100,0},{60,0},{60,60},{11,60}}, color={0,0,127}));
  connect(sine.y, controlBus.testBusVariable)
    annotation (Line(points={{-19,-40},{0,-40},{0,0}}, color={0,0,127}));
  annotation (experiment(__Dymola_fixedstepsize=0.001, __Dymola_Algorithm="Euler"),
      __Dymola_experimentFlags(Advanced(
        InlineMethod=0,
        InlineOrder=2,
        InlineFixedStep=0.001)),
    __Dymola_experimentSetupOutput(
      states=false,
      derivatives=false,
      inputs=false,
      outputs=false,
      auxiliaries=false,
      equidistant=false,
      events=false));
end TestBusConnector;

从 Dymola 2019 FD01 生成的代码如下所示：

include <dsblock6.c>

PreNonAliasNew(0)
StartNonAlias(0)
DeclareVariable("sine.amplitude", "Amplitude of sine wave", 1, 0.0,0.0,0.0,0,513)
DeclareVariable("sine.freqHz", "Frequency of sine wave [Hz]", 1, 0.0,0.0,0.0,0,513)
DeclareVariable("sine.phase", "Phase of sine wave [rad|deg]", 0, 0.0,0.0,0.0,0,513)
DeclareVariable("sine.offset", "Offset of output signal", 0, 0.0,0.0,0.0,0,513)
DeclareVariable("sine.startTime", "Output = offset for time < startTime [s]", 0,\
 0.0,0.0,0.0,0,513)
DeclareVariable("sine.y", "Connector of Real output signal", 0.0, 0.0,0.0,0.0,0,512)
DeclareVariable("const.k", "Constant output value", 0, 0.0,0.0,0.0,0,513)
DeclareVariable("const.y", "Connector of Real output signal", 0, 0.0,0.0,0.0,0,513)
DeclareOutput("y", "", 0, 0.0, 0.0,0.0,0.0,0,513)
DeclareAlias2("controlBus.testBusVariable", "Connector of Real output signal", \
"sine.y", 1, 5, 5, 1028)
EndNonAlias(0)

#define DymolaHaveUpdateInitVars 1
#include <dsblock5.c>

DYMOLA_STATIC void UpdateInitVars(double*time, double* X_, double* XD_, double* U_, double* DP_, int IP_[], Dymola_bool LP_[], double* F_, double* Y_, double* W_, double QZ_[], double duser_[], int iuser_[], void*cuser_[],struct DYNInstanceData*did_,int initialCall) {
}
StartDataBlock
EndDataBlock

翻译后的 modelica 代码 (dsmodel.mof) 仍然具有正弦块的计算。

// Translated Modelica model generated by Dymola from Modelica model 
//  TEMP.TEST.TestBusConnector


// -----------------------------------------------------------------------------

// Initial Section
  sine.amplitude := 1;
  sine.freqHz := 1;
  sine.phase := 0;
  sine.offset := 0;
  sine.startTime := 0;
  const.k := 0;
  const.y := 0;
  y := 0.0;




// -----------------------------------------------------------------------------

// Conditionally Accepted Section
  sine.y := (if time < 0 then 0 else sin(6.283185307179586*time));

// -----------------------------------------------------------------------------

// Eliminated alias variables
  // To have eliminated alias variables listed, set
  //   Advanced.OutputModelicaCodeWithAliasVariables = true
  // before translation. May give much output.

理想情况下，我希望模型转换为：

y := 0.0;

Answer 1

这不是您问题的直接答案，但仍然有助于提高性能。您试图避免的部分计算工作是通过计算结果文件中的变量而生成的。可以通过以下设置来避免这种情况：

可以使用以下方法将其设置为模型本身的注释：

  annotation (__Dymola_experimentSetupOutput(
      states=false,
      derivatives=false,
      inputs=false,
      auxiliaries=false));