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These are Posts that have been published by IanLisle

Hi all,

I seem to have triggered a nasty bug in Maple 17.  Consider the following code:

  BlahObject := module()
    option object;
    export BlahMethod := proc()
    local C, d, i;
      add(C[i]*d[i] + C[i], i=1..4);
    return NULL;
    end proc;
  end module;

It triggers a Maple kernel crash for me when doing object construction:

 B := Object(BlahObject);

The offending line is the one with add( ). It is ok if I add C[i]*d[i], but when the line contains both * and + it causes kernel death every time.  This is strange as the proc is not even being executed... only constructing the object. 

I am running Maple 17.02, it's also present in 17.01.  But interestingly, it runs fine in Maple 16.  Bug in Maple 17? 


The help page for  PDEtools,dsubs  says  "dsubs will substitute the left hand side of each substitution equation until this derivative is eliminated from the target"

Trying a subs like u'=u into the expression u'' gives u -- as it should:

PDEtools:-dsubs(diff(u(x),x) = u(x), diff(u(x),x,x));


One for the Maple bugkeepers. There seems to be a problem with DEtools[initialdata] -- in some circumstances the output initial data is wrong -- missing "D" operators. For instance, suppose one has a PDE system with dependent variables u(x), v(x,y). Then initialdata works. But if the PDE has dependent variabls u(x), v(y,x) then initialdata returns incorrect results.

Maple 10 (patched to 10.03) is inconsistent with its font choice in Maplet MathMLViewer elements when the fontsize option is set. If you don't set fontsize, then equations are typeset as expected with variables in italic font, just like in an ordinary Maple worksheet. But if you set fontsize to say 18pt, suddenly the variables are typeset in upright font. For instance try the following:
Eq := [diff(u(x,y),x)= diff(v(x,y),y), diff(u(x,y),y)=-diff(v(x,y),x)];
maplet := Maplet([
   [BoxCell("Fontsize 18:")],
In Maple 10 (patched to 10.03), there seems to be a bug in Typesetting[Suppress] when the function name is a Greek letter name. For instance the code interface(typesetting=extended): Typesetting[Suppress](eta(x)): diff(eta(x),x) = eta(x); should typeset like   η' = η or perhaps    d η / d x = η (depending on your "prime" settings). But one actually sees    η' = eta which is incorrect, or at least inconsistent and unexpected. More careful tests show that the whole Greek alphabet is affected similarly, apart from pi and zeta, which are handled slightly differently though still incorrectly.
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