expandAll error

[oden dengaku]

when I tried to expand below expression, error occured

( ( ( X3 - X1_c) * ( ( X1 + ( ( X4_c * X3 ) + X5_c)) + X3_b)) * ( ( X3 - X1 ) + ( X3_c + X5 )))

and error is

Exception in thread "main" java.lang.IllegalArgumentException: Comparison method violates its general contract! at java.util.TimSort.mergeHi(TimSort.java:899) at java.util.TimSort.mergeAt(TimSort.java:516) at java.util.TimSort.mergeCollapse(TimSort.java:441) at java.util.TimSort.sort(TimSort.java:245) at java.util.Arrays.sort(Arrays.java:1512) at org.matheclipse.core.eval.Range.sort(Range.java:764) at org.matheclipse.core.eval.EvalAttributes.sort(EvalAttributes.java:187) at org.matheclipse.core.eval.EvalEngine.evalFlatOrderlessAttributesRecursive(EvalEngine.java:926) at org.matheclipse.core.eval.PlusOp.plus(PlusOp.java:271) at org.matheclipse.core.reflection.system.Expand$Expander.expandPlusTimesPlus(Expand.java:299) at org.matheclipse.core.reflection.system.Expand$Expander.expandTimesBinary(Expand.java:272) at org.matheclipse.core.reflection.system.Expand$Expander.expandTimes(Expand.java:256) at org.matheclipse.core.reflection.system.Expand$Expander.expandAST(Expand.java:63) at org.matheclipse.core.reflection.system.Expand.expand(Expand.java:425) at org.matheclipse.core.reflection.system.ExpandAll.expandAll(ExpandAll.java:78) at org.matheclipse.core.reflection.system.ExpandAll.evaluate(ExpandAll.java:27) at org.matheclipse.core.eval.EvalEngine.evalASTBuiltinFunction(EvalEngine.java:721) at org.matheclipse.core.eval.EvalEngine.evalASTArg1(EvalEngine.java:655) at org.matheclipse.core.eval.EvalEngine.evalAttributes(EvalEngine.java:751) at org.matheclipse.core.eval.EvalEngine.evalAST(EvalEngine.java:588) at org.matheclipse.core.expression.AbstractAST.evaluate(AbstractAST.java:659) at org.matheclipse.core.eval.EvalEngine.evalLoop(EvalEngine.java:997) at org.matheclipse.core.eval.EvalEngine.evalWithoutNumericReset(EvalEngine.java:1396) at org.matheclipse.core.eval.EvalEngine.evaluate(EvalEngine.java:1341) at org.matheclipse.core.eval.ExprEvaluator.evaluate(ExprEvaluator.java:205) at org.matheclipse.core.eval.ExprEvaluator.evaluate(ExprEvaluator.java:225)

I know in some case Timsort cause this type of error (A<B and B<A in one eval), but I dont know why error occurs in this evalation. Is there any restriction on variable name?

Thanks.

[Axel Kramer]

Some variable names are parsed as patterns Is this intended?

If not, don't use '_' (underscores) in variable names.

For example x1_c:

[oden dengaku]

No, X1_c is a one variable,so I don't want to separate it. Should I name variables in one character? I wonder this error occurs rarely.

[Axel Kramer]

x1_c is parsed as pattern "x1_" with condition "c". You can use the '$' sign as a special character in symbol names.

Nethertheless this is a bug, which has to be solved.

[oden dengaku]

Can I use "$x1_c" or "$x1$_c"?

[oden dengaku]

I tried both, but the result was same.

This is the code trying to expand.

---

    String fExpInOrder; //fExpInOrder is expression I want to expand.
    ExprEvaluator util = new ExprEvaluator(true, 0);
    IExpr result = util.evaluate("ExpandAll(" + fExpInOrder + ")");
    fExpandFomula = result.toString();

---

These are the expressions error occur.

( ( $X2_c + ( $X2 - ( $X3_a - $X1 ) ) ) * ( $X2 + ( ( ( $X1_c + $X1 ) + ( ( $X1_a + ( ( $X4_a + $X1_c ) + $X2 ) ) - $X3_b ) ) + ( $X5_b + ( ( ( ( $X2_b + $X5 ) * ( $X2_b - $X4 ) ) * $X3 ) + $X1 ) ) ) ) )

( ( ( ( ( X3$_b - X1$_c ) - ( X3 - ( ( X2$_a + X3$_c ) - X5$_a ) ) ) - X1 ) - X5 ) * ( X4 + ( ( X3 * ( X1$_b - X1 ) ) + X1$_c ) ) )

below is a sample expression that is expanded corrctly.

( X5 - ( ( ( X1$_c - ( ( X5$_b + X3$_c ) + X1 ) ) + X3 ) * ( ( X4$_a + ( ( ( X1 - X3$_b ) * X5$_b ) + X2$_a ) ) - X5$_c ) ) )

to

x5+x1x2$_a-x3x2$_a-x1$_cx2$_a+x2$_ax3$_c+x1x4$_a-x3x4$_a-x1$_cx4$_a+x3$_cx4$_a-x1x3x5$_b-x1x1$_cx5$_b+x2$_ax5$_b-x1x3$_bx5$_b+x3x3$_bx5$_b+x1$_cx3$_bx5$_b+x1x3$_cx5$_b-x3$_bx3$_cx5$_b+x4$_ax5$_b-x1x5$_c+x3x5$_c+x1$_cx5$_c-x3$_cx5$_c-x5$_bx5$_c+x5$_bx1^2+x1x5$_b^2-x3$_bx5$_b^2

[Axel Kramer]

I meant: ExpandAll(( ( ( X3 - X1$c) * ( ( X1 + ( ( X4$c * X3 ) + X5$c)) + X3$b)) * ( ( X3 - X1 ) + ( X3$c + X5 ))))

[Axel Kramer]

I fixed the exception with commit: de90402

The fix still needs some additional clean up for output of special cases like:

a+b-Infinity

[Axel Kramer]

See commit e4389ab

[oden dengaku]

Oh! Thank you for your help!!