March 2015 - GiNaC-list

compile_ex with more than two symbols in the expression
by William Silva 01 May '15

01 May '15

Dear all, Is there a way to use "compile_ex" with more than 2 free variables? I am generating several expressions using .diff() and would like to compile them into C functions and attach function pointers. Using the .subs() method is too slow for my code. Unfortunately my expressions contain more than just two symbolic variables. Ideally I would love to have a FUNCP_nP typedef that can accept a list or array of n symbolic variables and use a compile_ex function that accepts an lst of the symbols. I noticed that the FUNCP_CUBA typedef sort of does this, but I am not sure how to access the compiled function. Any help or pointers would be greatly appreciated! Best, Will S.

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Symbolic Integration of exponential functions
by Matthias Reis 27 Apr '15

27 Apr '15

Dear all, as far as I understand, ginac cannot integrate anything other than polynomials. How hard would it be (for me maybe) to implement exponentials? What needs to be done? This feature would be great for me. I just need to integrate simple e^{x * constant} terms. Best regards, Matthias

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Piecewise function
by Christophe Trophime 12 Mar '15

12 Mar '15

Hi, I am using GiNac within a Finite Element Library Feel++. I would to define piecewise function in GiNaC. Is this possible with latest version? Thank for any hints Best regard C. Trophime Christophe TROPHIME Research Engineer CNRS - LNCMI 25, rue des Martyrs BP 166 38042 GRENOBLE Cedex 9 FRANCE Tel : +33 (0)4 76 88 90 02 Fax : +33 (0) 4 76 88 10 01 Office U 19 M@il : christophe.trophime(a)lncmi.cnrs.fr

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Manipulation with matrice
by Fmant Dolch 08 Mar '15

08 Mar '15

Hi. In tutorial said there is lst_to_matrix method to create matrix from list of lists. If i want to change some rows in matrice, do i need firsst change list of lists then convert to matrix or there is some direct way to do it?

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list differentiation
by soppon 01 Mar '15

01 Mar '15

Hi. Here two programs. dif1 return 0 for list1 and working well for list2, dif2 return the rigth answer, but if you change table argument x to y on line 12, then get segmentation fault. What should i do?

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list input
by soppon 01 Mar '15

01 Mar '15

Hi. I'm trying to use list as input. List as output prints {expr1,expr2,..}, list.nops() is varying. When I write list as: parser reader; somelist=reader(cin); where input to cin: {expr1,expr2,..} at the end shift-D It returns somelist={expr1,expr2,..}, somelist.nops()=1. When accessing the 2nd and higher element of list, program gets segmentation fault.

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