symja_android_library/Lobby

Symja - Java computer algebra library - https://github.com/axkr/symja_android_library

Axel Kramer

@axkr

<module>matheclipse-external</module>
        <module>matheclipse-frontend</module>
        <module>matheclipse-core</module>
        <module>matheclipse-api</module>
        <module>matheclipse-io</module>

Евгений Буйволов

@ereborDeveloper

Thanks! Found it in unit tests. How should I properly listen for change log? Instead of reading commits I mean

Axel Kramer

@axkr

A short summary of changes can be found in the release notes:

https://github.com/axkr/symja_android_library/releases

Евгений Буйволов

@ereborDeveloper

Ahh! Thanks! Very helpful

TiMauzi

@TiMauzi

@axkr Hello, I just found the Symja project while looking for a Java CAS. Did you happen to publish any papers concerning your work on this library? Would be very helpful, since I am working on a thesis at the moment! Thank you in advance! :)

Axel Kramer

@axkr

@TiMauzi No there is no paper.

There is the tutorial with the available functions in markdown: https://github.com/axkr/symja_android_library/tree/master/symja_android_library/doc

And there is the Wiki section https://github.com/axkr/symja_android_library/wiki

A feature "highlight" is the port of the RUBI integration engine: https://github.com/axkr/symja_android_library/wiki/Porting-Rubi-Integration-rules-to-Symja

Axel Kramer

@axkr

Another is the "partial" Wolfram language package support: https://github.com/axkr/symja_android_library/wiki/Context

The Compile function https://github.com/axkr/symja_android_library/blob/master/symja_android_library/doc/functions/Compile.md will be independent from the JDK in next version and will be realized with the Janino compiler: http://janino-compiler.github.io/janino/

TiMauzi

@TiMauzi

@axkr Too bad there is no paper... Thank you nevetheless for the information! :)

TiMauzi

@TiMauzi

@axkr Different question... does Symja have a method to get all literals within an IExpr object? E.g. if I have "a || b && c || c", is there a function that returns "[a, b, c, c]"?

Axel Kramer

@axkr

@TiMauzi https://github.com/axkr/symja_android_library/blob/master/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/convert/VariablesSet.java

The BooleanVariables() function use this internally https://github.com/axkr/symja_android_library/blob/master/symja_android_library/doc/functions/BooleanVariables.md

TiMauzi

@TiMauzi

@axkr Awesome, thank you!

TiMauzi

@TiMauzi

@axkr And is there a method to invert a logical expression with De Morgan's Laws? Something like "a || b" => "!(!a && !b)"?

TiMauzi

@TiMauzi

Something like "use only '&&' and '!' but no '||'"

TiMauzi

@TiMauzi

Nice, I think I managed already:

deMorgan1 = {x_ || y_ :> !(!x && !y)}
deMorgan2 = {x_ && y_ :> !(!x || !y)}
ReplaceRepeated(fox || rabbit || chicken, deMorgan1)

... leads to: ¬(¬fox∧¬rabbit∧¬chicken), perfect :)

Axel Kramer

@axkr

@TiMauzi I'm not sure what you want to get exactly, but BooleanConvert may also be an option?

https://github.com/axkr/symja_android_library/blob/master/symja_android_library/doc/functions/BooleanConvert.md

TiMauzi

@TiMauzi

No, this is not what I want, since "a || b || c" would always stay the same with BooleanConvert, while I want it to become "!(!a && !b && !c)".

I want to write a formula with only "&&"s or only "||"s, and I think that's what my deMorgan1/deMorgan2 replacements are doing

TiMauzi

@TiMauzi

The BooleanVariables() function use this internally https://github.com/axkr/symja_android_library/blob/master/symja_android_library/doc/functions/BooleanVariables.md

@axkr Is there a way of outputting the list/set created by BooleanVariables() or Variables() to a Java list or Java array?

Without doing some usual pattern matching, of course :)

Axel Kramer

@axkr

@TiMauzi something like this?

private static List<IExpr> booleanVariables(final IExpr expr) {
      VariablesSet eVar = new VariablesSet();
      eVar.addBooleanVarList(expr);
      return eVar.getArrayList(); 
}

TiMauzi

@TiMauzi

I did it the following way now:

private static String[] getVariablesArray(IExpr variables) throws MathException, StackOverflowError, OutOfMemoryError {
    return variables.toString()
            .replaceAll("\\{", "")
            .replaceAll("}", "")
            .replaceAll(" ", "")
            .split(",");
}

With IExpr calcExpr = evaluator.eval("Variables(" + calc + ")"); and calc being my formula

And then getVariablesArray(calcExpr);

Since I need the string representation anyway, I think the effort is similar, no?

Axel Kramer

@axkr

If you use regex it might be slower:

https://stackoverflow.com/questions/6262397/string-replaceall-is-considerably-slower-than-doing-the-job-yourself

TiMauzi

@TiMauzi

Good to know, thanks for the hint!

I'll try your approach later, then :)

TiMauzi

@TiMauzi

@axkr In https://github.com/axkr/symja_android_library/blob/d1e78f694be9b7b0bea4abbacbd924c8512adc38/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/F.java#L3907 there is the following part of the code:

        String autoload = ".\\Autoload";
        if (FEConfig.PARSER_USE_LOWERCASE_SYMBOLS) {
          autoload = ".\\AutoloadSymja";
        }
        File sourceLocation = new File(autoload);

Symja creates a file here. Since I'm writing an Elasticsearch plugin, creating files doesn't seem to be allowed. Is there a way of using Symja without addtional files being implicitly created by ExprEvaluator?

Axel Kramer

@axkr

@TiMauzi can you please try something like this for automatically loading init scripts:

Axel Kramer

@axkr

try {
          String autoload = ".\\Autoload";
          if (FEConfig.PARSER_USE_LOWERCASE_SYMBOLS) {
            autoload = ".\\AutoloadSymja";
          }
          File sourceLocation = new File(autoload);
          final String[] files = sourceLocation.list();
          if (files != null) {
            for (int i = 0; i < files.length; i++) {
              if (files[i].endsWith(".m")) {
                File sourceFile = new File(sourceLocation, files[i]);
                FileFunctions.Get.loadPackage(EvalEngine.get(), sourceFile);
              }
            }
          }
        } catch (java.security.AccessControlException acex) {
          // no read access for current user
          acex.printStackTrace();
        } catch (RuntimeException ex) {
          ex.printStackTrace();
        }

TiMauzi

@TiMauzi

@axkr Following output if I place this test right in front of the part of my plugin that crashes when executed:

[2021-05-14T00:21:32,244][WARN ][stderr                   ] [TIM] java.security.AccessControlException: access denied ("java.io.FilePermission" ".\AutoloadSymja" "read")
[2021-05-14T00:21:32,245][WARN ][stderr                   ] [TIM]       at java.base/java.security.AccessControlContext.checkPermission(AccessControlContext.java:472)
[2021-05-14T00:21:32,246][WARN ][stderr                   ] [TIM]       at java.base/java.security.AccessController.checkPermission(AccessController.java:1036)
[2021-05-14T00:21:32,246][WARN ][stderr                   ] [TIM]       at java.base/java.lang.SecurityManager.checkPermission(SecurityManager.java:408)
[2021-05-14T00:21:32,246][WARN ][stderr                   ] [TIM]       at java.base/java.lang.SecurityManager.checkRead(SecurityManager.java:747)
[2021-05-14T00:21:32,247][WARN ][stderr                   ] [TIM]       at java.base/java.io.File.list(File.java:1131)
[2021-05-14T00:21:32,247][WARN ][stderr                   ] [TIM]       at org.elasticsearch.index.search.CommutingQuantumScorer.score(CommutingQuantumScorer.java:96)
...

(The last method before I skipped the rest is the method I placed the test in.)

TiMauzi

@TiMauzi

I found out that Elasticsearch doesn't want people to have any FilePermission. That's why I asked if there is any way to not letting Symja create some file

Axel Kramer

@axkr

@TiMauzi If you don't need any scripts, do you need an option to simply skip the autoload part?

TiMauzi

@TiMauzi

What kind of "scripts" do you mean?

formulaEvaluator.eval("deMorganDisCon = {x_ || y_ :> !(!x && !y)}");
formulaEvaluator.eval("deMorganConDis = {x_ && y_ :> !(!x || !y)}");

Something like this? ^-^' @axkr

If you mean this, then it might hurt a bit but I might be able to solve it in another way.

Axel Kramer

@axkr

I meant "script" packages which could be automatically loaded on startup like this one: https://github.com/axkr/symja_android_library/wiki/context

TiMauzi

@TiMauzi

Oh you mean that >>I<< want to use external files? Then no

In this case I don't need any scripts

I just need the basic symja functionalities @axkr

TiMauzi

@TiMauzi

@axkr So you mentioned an option to skip the autoload part, is there any I'm not aware of? :O

Axel Kramer

@axkr

no I have to introduce it.

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