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lukamar

These two lines should evaluate to the same expression, but the second one fails:

eval('output' = 'id');
eval('output'='id')

It seems that '=' gets parsed in advance to at_equal, but the single quotes do not pertain to =.

lukamar

Hi,
I have the same problem in Ubuntu 20.04. The problem is possibly in the function

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bool History_Pack::save_as(const char * filename,const char * ch,bool autosave_rm,bool warn_user,bool savecontext)

in History.cc, somewhere between the lines 1964 and 1982 where Fl::focus is called...

lukamar

It seems that using e as a symbol in the expression e*x+d is the problem. In giac, it is the base of natural logarithm (a predefined constant). Nevertheless, using it shouldn't crash icas.

lukamar

"epsilon" and "Gamma" (uppercase gamma) are built-in function names, so they can't be used as symbols. If I'm not mistaken, all other greek symbols which are different from Latin letters (alpha, beta etc.) are available. If you want to use epsilon as a symbol you may use: eps:=make_symbol("epsilon")...

lukamar

Yes, here it is: the latex code \mathrm{xy\_0\_1} gets converted to x_{\mathrm{0_1}}, which causes the sub-subscript "1" because the inner underscore is not prefixed by \. Shouldn't the result rather read as x_{\mathrm{0\_1}}?

lukamar

Maybe the patch creates sub-subscripts recursively? Since you moved mathrm from \mathrm{var_index1_index2} to the first index, obtaining var_\mathrm{index1_index2}, the patch does its work again on the new subscript. I will change the default behavior for indices for numeric subscripts, so that they...

lukamar

That's intended too, only in the latest version x_0_1 is displayed with "0_1" in subscript (there are no sub-subscripts). The default behavior is to add subscripts only to 1-character symbols (like x_index, but not xy_index). It seemed more likely to me that variables with names like "xy_index" are ...

lukamar

Hi Matt, this behavior is intended. The conversion routine favors implicit multiplication, explicitly indicating the dot only when the result would be ambiguous otherwise. For example, when multi-character variables are involved (note that they are printed in upright font), which would end up concat...

lukamar

A maybe related problem: solve now crashes with the following command:

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solve([-4*y*x^2*z-4*y*z+4*y+3*x^4-2*x^3+2*x^2+4*x*z-2*x-1,-y*x+y+z*x-z,-2*y^2-4*y*x*z+x^3-x^2-x-2*z^2+1],[x,y,z])

lukamar

Thanks!
I corrected graphe.h, const was missing in more than one instance.

lukamar

Hi Bernard,

"solve" in the source from Oct 30 fails on this command:

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solve([3*x^2-3*z^2,3*y^2-3*z^2,x*y+y*z+x*z-x*y*z],[x,y,z])

The solution is [3,3,3]. I get the error message "Unable to find a separation form for the RUR computation". Maybe it's a regression due to the new functionality?

lukamar

Everything is fine in Xcas 1.7.0-35 in Windows.

lukamar

Hi, By solving the system in giac 1.7.0-25 sol:=solve([(2*x1^5+4*x1^3+2*x1*x2+2*x1)/(x1^2*x2+x2),x1^4+2*x1^2+x2^2-3],[x1,x2]) I get four solutions: [[0,sqrt(3)],[0,-(sqrt(3))],[sqrt((sqrt(2*(sqrt(17)-1))-2)/2),(-(sqrt(17))+1)/2],[-(sqrt((sqrt(2*(sqrt(17)-1))-2)/2)),(-(sqrt(17))+1)/2]] However, the s...

lukamar

Hi, There's a strange thing happening when substituting in giac 1.7.0-25: s:=subs(ln(1+x1^2)-x2,[x1=-sqrt((sqrt(2*(sqrt(17)-1))-2)/2),x2=(-sqrt(17)+1)/2]) Since values for x1 and x2 are both real, the result should obviously be real also. However, the command im(s) gives (1-i)*pi/2 which is strange ...

lukamar

Thanks, it works!

Le forum de XCAS

La recherche a retourné 331 résultats

parser problem

Re: "autosave" feature moves focus to the application

Re: collection of issues found in 1.9-07

Re: Greek letters for variable names

Re: Latex revisited

Re: Latex revisited

Re: Latex revisited

Re: Latex revisited

Re: possible regression in solve

Re: possible regression in solve

possible regression in solve

Re: solve returning infeasible solution

solve returning infeasible solution

false nonzero imaginary part after real substitution

Re: solve crash