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May 2023

4 participants
2 discussions

Any way to get the leading order of a series expansion?
by Vitaly Magerya 16 May '23

16 May '23

Hi, all. We have some code needs to have the first N orders of a series expansion of an expression; so far we've been actually using sympy for this: there one can use series() [1] directly, as it computes "the first N orders", whereas in GiNaC series() expands "up to N-th order", so if I just need e.g. the leading order, then series() can't help me directly. Any idea of how can one get the leading order, or the first N orders with GiNaC? Would this need a lot of effort to implement? [1] https://docs.sympy.org/latest/modules/series/series.html#sympy.series.serie…

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Polynomial Factoring
by Charles White 05 May '23

05 May '23

Hi GiNaC! I love the library! Keep up the good work! Currently I am trying to find exact eigenvalues. My solution so far is to factor the characteristic equation then I can try to find roots of the factored polynomials. But, I need a list of expressions that store the factored polynomials. For example in the ginsh I have: ``` > rat = pow(x,6)+1; 1+x^6 > factor(rat); (1+x^4-x^2)*(1+x^2) ``` Then I need a list with the expressions (1+x^4-x^2) and (1+x^2); from there I can calculate the roots exactly. Is this possible? Is there a better way to find exact eigenvalues? Thanks! Charles

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