*_init.xml and bounded nominal values

[Lennart Ochel]

The *_init.xml file contains if a nominal value is used and if so also the nominal value itself for all variables. In the case of dependent nominal values (i.e., parameter bounded) the xml-file contains always "useNominal=false, nominal=1.0".
This got fixed for the simulation in r19183, so that useNominal gets overwritten during runtime if needed. However, the xml-file still contains "useNominal=false, nominal=1.0". This is very confusing and should be fixed.

[Lennart Ochel]

Come on - you can fix it.

Any comments on how to fix it? The straightforward solution would be a new attribute boundedNominalValue={false|true} in the xml-file, right? I don't like it very much, but still better than now. Any better ideas?

[Lennart Ochel]

same for start, min and max.

[Vitalij Ruge]

This statement
useNominal=false, nominal=1.0
is correct. We don't use 1.0 as nominal.

[Lennart Ochel]

No, it is not correct. Please, check the following example from the test suite:

// testsuite/simulation/modelica/initialization/bug_2207.mos
  model bug_2207
    parameter Real a=100;
    constant Real b=100;
    Real x(start=2*a, nominal=3*a, min=-4*a, max=5*a);
    Real y(start=2*b, nominal=3*b, min=-4*b, max=5*b);
  equation
    der(x) = 0;
    der(y) = 0;
  end bug_2207;

The file 'initializationTests.bug_2207_init.xml' contains following information:

  <ScalarVariable
  name = "x"
  valueReference = "1001"
  variability = "continuous" isDiscrete = "false"
  causality = "internal" isValueChangeable = "true"
  alias = "noAlias"
  classIndex = "1" classType = "rSta"
  fileName = "&lt;interactive&gt;" startLine = "7" startColumn = "5" endLine = "7" endColumn = "54" fileWritable = "true">
  <Real useStart="false" start="0.0" fixed="false" useNominal="false" nominal="1.0" />
  </ScalarVariable>

useNominal="false" nominal="1.0" is obviously confusing. There is useNominal=false to make clear that nominal="1.0" is not given in the model. But it is not possible to determine if either there is no nominal value given and 1.0 is used as default value or a parameter bounded nominal value is defined as in this example.

[Lennart Ochel]

I propose to introduce new Boolean entities "dependentNominal", "dependentStart", "dependentMin", and "dependentMax". The actually entities "nominal", "start", "min", and "max" should then contains the actual expression. Hence, the example from above would become the following:

<Real useStart="false" dependentStart="false" start="0.0" fixed="false" 
      useNominal="false" dependentNominal="true" nominal="3*a" dependentMin="true" 
      min="4*a" dependentMax="true" max="5*a" />

BTW: I am not sure if we need the useStart attribute at all.

[Lennart Ochel]

I changed the handling for nominal values in r19239. Now, the XML file Looks like:

[...]
<ScalarVariable
  name = "y"
  valueReference = "1000"
  variability = "continuous" isDiscrete = "false"
  causality = "internal" isValueChangeable = "true"
  alias = "noAlias"
  classIndex = "0" classType = "rSta"
  fileName = "&lt;interactive&gt;" startLine = "8" startColumn = "5" endLine = "8" endColumn = "54" fileWritable = "true">
  <Real useStart="true" start="200.0" fixed="false" useNominal="true" nominal="300.0" min="-400.0" max="500.0" />
</ScalarVariable>
<ScalarVariable
  name = "x"
  valueReference = "1001"
  variability = "continuous" isDiscrete = "false"
  causality = "internal" isValueChangeable = "true"
  alias = "noAlias"
  classIndex = "1" classType = "rSta"
  fileName = "&lt;interactive&gt;" startLine = "7" startColumn = "5" endLine = "7" endColumn = "54" fileWritable = "true">
  <Real useStart="false" start="0.0" fixed="false" useNominal="true" />
</ScalarVariable>
[...]

[Martin Sjölund]

Replying to lochel:

BTW: I am not sure if we need the useStart attribute at all.

Doesn't OMEdit use this?

[Lennart Ochel]

OMEdit is not using that attribute. I used it for an old initialization approach. Probably it is obsolete and the useStart attribute can be removed. Moreover, it is not compliant to the specification.

[Lennart Ochel]

Fixed in r19255 (see also #2601).