La recherche a retourné 120 résultats
Aller sur la recherche avancée
- jeu. avr. 18, 2024 4:49 am
- Forum : Giacpy
- Sujet : Disabling Groebner basis memory parses
- Réponses : 3
- Vues : 906
Re: Disabling Groebner basis memory parses
Sorry for the late reply. I got a bit busy with teaching. Thank you Bernard. Though, I wouldn't want you to go through the trouble if I'm the only one asking for it. I got the job done nevertheless. But maybe I can help debug or improve the codebase: It seems that the time that is parsed is differen...
- sam. avr. 06, 2024 2:56 pm
- Forum : Giacpy
- Sujet : Disabling Groebner basis memory parses
- Réponses : 3
- Vues : 906
Disabling Groebner basis memory parses
Hello, Is there a way to disable memory parses from the Groebner basis computation of giac when calling it via giacpy? If I call gbasis from giacpy I always get // Groebner basis computation time 6.3e-005 Memory -1e-006M These parses are not ideal if I query for Groebner basis a lot of time. For ins...
- jeu. juin 25, 2020 3:51 am
- Forum : Giac
- Sujet : sturm vs fsolve
- Réponses : 2
- Vues : 3125
Re: sturm vs fsolve
Thanks for the hint Bernard!
- mar. juin 23, 2020 11:48 am
- Forum : Giac
- Sujet : sturm vs fsolve
- Réponses : 2
- Vues : 3125
sturm vs fsolve
Hi, I had the impression that sturm has a better runtime than fsolve when trying to find if a univariate polynomial has a root in an interval. It seems that I am wrong at least for Giac. Has anyone tried experimenting on sturm for a univariate polynomial say of degree 11? Because of my application, ...
- lun. avr. 15, 2019 11:09 am
- Forum : Giacpy
- Sujet : Groebner basis evaluation time is different
- Réponses : 5
- Vues : 4801
Re: Groebner basis evaluation time is different
As always, thanks for this enlightening explanation Bernard! Yes, I will try to do benchmark of more polynomial systems (not just katsura9, as you say katsura>11 if this will show the power of giac!) to show the full power of giac. Anyway, now at least I understand. It seems though that in poly.lib ...
- sam. avr. 13, 2019 10:05 am
- Forum : Giacpy
- Sujet : Groebner basis evaluation time is different
- Réponses : 5
- Vues : 4801
Groebner basis evaluation time is different
I made a code for Katsura 9 Groebner basis benchmark as follows: from giacpy import giac, gbasis from time import clock, time #katsura n, change n as pleased.. n=9 x=[] ideal=[] for i in xrange(n+1): s= "x" + str(i) x.append(giac(s)) # x_0 + 2\sum_{i=1}^n x_i = 1 f=x[0] for i in xrange(1,n+1): f += ...
- mar. févr. 19, 2019 4:34 am
- Forum : Xcas - English
- Sujet : some problem with determinant of a matrix
- Réponses : 4
- Vues : 2168
Re: some problem with determinant of a matrix
Thank you Luka and Bernard. I guess I should have known better, I often encounter this and I always forget that at times I should switch to rationals. Maple has similar pecularities when you don't make your float rationals. In case you want to look at this more, I think that when working with less s...
- lun. févr. 18, 2019 10:12 am
- Forum : Xcas - English
- Sujet : some problem with determinant of a matrix
- Réponses : 4
- Vues : 2168
some problem with determinant of a matrix
Consider the following code m:=matrix[[0,0.425*v2,-0.425,0,0,-d5*l4+d5*l5,d5*l4*v5+d5*v5*l5],[0,0.425,0.425*v2,0,0,-d5*l4*v5-d5*v5*l5,-d5*l4+d5*l5],[0.425,0,0,-0.425*v2,d5*l4*l5*v5-d5*v5,0,0],[-2*v2,0,0,2,2*l4*l5*v5+2*v5,0,0],[0,-2*v2,-2,0,0,2*l4*v5-2*v5*l5,2*l4+2*l5],[0,2,-2*v2,0,0,-2*l4-2*l5,2*l4*...
- sam. févr. 16, 2019 11:04 pm
- Forum : Giacpy
- Sujet : normalizing numeric polynomials
- Réponses : 4
- Vues : 4086
Re: normalizing numeric polynomials
This is not giacpy related, I have a similar problem with n>=12: whatever is epsilon or Digits. n:=12:; expand((evalf(10**n,100)*x^2+x)/evalf(10**n,100)) (I put evalf with 100 digits to avoid global Digits or epsilon2zero limitations. Bernard, is there some epsilon2zero use in this division? or is ...
- ven. févr. 08, 2019 12:18 pm
- Forum : Giacpy
- Sujet : normalizing numeric polynomials
- Réponses : 4
- Vues : 4086
normalizing numeric polynomials
Consider the following code from giacpy import giac giac("printpow(1)") f=giac("3.02565028105e+042*x^2+x") print (f/f.lcoeff("x")).expand() The above returns 0, but it must return a normalized f (f divided by the coefficient of the monomial with highest degree). Any ideas how to resolve this? Jose
- ven. févr. 08, 2019 10:32 am
- Forum : Xcas - English
- Sujet : getting the coefficient matrix
- Réponses : 1
- Vues : 1234
getting the coefficient matrix
Hi, Is there an efficient way of getting the coefficient matrix of a system of linear equations eqns with variable vars? I want something like: get_coeff_matrix(eqns,vars) I know I could just loop through the vars and ask for coefficients but I think this is not very efficient (for instance in maple...
- mar. janv. 15, 2019 4:49 pm
- Forum : Giacpy
- Sujet : fsolve and giacpy undef return
- Réponses : 3
- Vues : 3527
Re: fsolve and giacpy undef return
That is a cause of concern. In any case, Xcas for windows has lapack and blas dependencies precompiled (actually they are cyg librarires, but one can compile directly with lapack and blas dlls in mingwc). I'm not sure what fsolve of giac is dependent on, but its not unreasonable to depend on lapack ...
- mar. janv. 15, 2019 10:27 am
- Forum : Xcas - English
- Sujet : irreducibility check for polynomials
- Réponses : 0
- Vues : 1279
irreducibility check for polynomials
Hi, I was wondering if there is any irreducibility check (for say integral multivariable polynomials), something like say "is_irreduc"? I can always use "factors" or "factor" to check manually. But there are several reasons why irreducibility check is more useful: 1. Programmatically getting a bool ...
- jeu. janv. 10, 2019 4:25 pm
- Forum : Giac
- Sujet : graph theory commands for Giac
- Réponses : 198
- Vues : 65748
Re: graph theory commands for Giac
Hi, Just want to bump here. I don't know the intricacies of your developments and I don't know if it helps. Maybe its worth mentioning that I compile nauty for windows (independent of giac) as a separate dll (in fact I compile with msvc which is rarely possible for math libraries). So I suppose your...
- jeu. janv. 10, 2019 4:18 pm
- Forum : Giacpy
- Sujet : fsolve and giacpy undef return
- Réponses : 3
- Vues : 3527
fsolve and giacpy undef return
Consider the following code in python using giacpy: from giacpy import giac, fsolve giac("printpow(1)") p1 = giac("-0.001*x2^3-0.09*x0*x2^2+0.317480210394*x2^3+0.251984209979*x0*x2^2-2.8*x0^2*x2-0.1*x2-4.2*x2^2-3.17480210394*x0^2*x2-12.6992084157*x0*x2^2-2.51984209979*x0^3-10.0793683992*x0^2*x2-28*x...