La recherche a retourné 118 résultats

par jocaps
ven. nov. 30, 2018 10:51 am
Forum : Giacpy
Sujet : Getting the monomials of a polynomial
Réponses : 4
Vues : 1515

Re: Getting the monomials of a polynomial

Thanks fréderic. Though it seems to be a lot of work just for a list of monomials. I guess I will use it if the number of such monomials are rather long otherwise it will not be too expensive to just use "part".
par jocaps
dim. nov. 25, 2018 4:10 pm
Forum : Giacpy
Sujet : Getting the monomials of a polynomial
Réponses : 4
Vues : 1515

Re: Getting the monomials of a polynomial

I know this is an old thread, but I want to point out on something in the last answer of frederic. The proposed method does not necessarily give me the correct list. Consider the following for instance from giacpy import giac x,y,z=giac('x,y,z') P=x**2 + x +y Q=(P.ratnormal()) # here sommet is * (nu...
par jocaps
mar. nov. 20, 2018 1:47 pm
Forum : Xcas - English
Sujet : Why does linsolve not give a solution
Réponses : 3
Vues : 510

Re: Why does linsolve not give a solution

What did you try exactly? If I run linsolve(gb[0:2],vars[0:2]), I get [-16*t**2+8,-16*t+16] gb is already the solution. I tried linsolve(ideal, giac("[b_0_8,b_0_9]") Technically the solution is already in ideal (so of course I could choose these from ideal), but I guess the extra equations in the b...
par jocaps
mar. nov. 20, 2018 9:09 am
Forum : Xcas - English
Sujet : Why does linsolve not give a solution
Réponses : 3
Vues : 510

Why does linsolve not give a solution

Hi, I have a system of equations which are clearly linear with respect to some of the variables (in my problem these are b_0_8 and b_0_9). So technically one should be able to get the solution using only linsolve for solving only these variables. In giac I am able to arrive to the solution using Gro...
par jocaps
ven. nov. 02, 2018 2:25 pm
Forum : Giacpy
Sujet : extracting only the polynomial entry in factors
Réponses : 2
Vues : 535

Re: extracting only the polynomial entry in factors

I kind of resolved this by just asking the indets. So I went to each of the elements of the list, step 2 (since the second entry is the multiplicity), and ask if indets have length 0, if so I know they are constant.
par jocaps
ven. nov. 02, 2018 2:00 pm
Forum : Giacpy
Sujet : extracting only the polynomial entry in factors
Réponses : 2
Vues : 535

extracting only the polynomial entry in factors

Hi, I want to be able to get the polnyomial factors of a polynomial but I'm not sure what is the best way to do this in giac or giacpy. So for instance I have a polynomial say 2/3*(x+y*x+3) and I use the factors command I get [2,1,x*y+x+3,1,3,-1] In my actual codes this polynomials could be really l...
par jocaps
ven. oct. 12, 2018 10:32 pm
Forum : Xcas - English
Sujet : How to solve this system of equation in Xcas
Réponses : 3
Vues : 563

Re: How to solve this system of equation in Xcas

Hi Bernard, My unknowns are x,y,z and w. I think the solutions are parametrizable surfaces, so it can be parametrized by at least 2 parameters and not less. So we could assume the unknowns to be say z and w. But here, giac is struggling to find a solution (computation in my laptop does not end). Edi...
par jocaps
jeu. oct. 11, 2018 8:06 am
Forum : Giacpy
Sujet : giacpy 0.6.7
Réponses : 1
Vues : 919

Re: giacpy 0.6.7

Dear Frederic,

Thank you for your hard and amazing work! I confirm that this works for me (including the nauty functionality). Wonderful!

Jose
par jocaps
jeu. oct. 11, 2018 7:58 am
Forum : Xcas - English
Sujet : How to solve this system of equation in Xcas
Réponses : 3
Vues : 563

How to solve this system of equation in Xcas

Hi, I have a system of equations over Q(rootof(z^3-2)) that if I give in maple I get solutions with different branches and some of them are given as algebraic numbers. The code in maple looks like this: p1 := 2*RootOf(_Z^3-2)^2*z*x^2+8*RootOf(_Z^3-2)^2*z^2*x+2*x^3*RootOf(_Z^3-2)+8*x^2*RootOf(_Z^3-2)...
par jocaps
mer. sept. 19, 2018 8:50 am
Forum : Xcas - English
Sujet : Converting a float polynomial to integer polynomial
Réponses : 2
Vues : 329

Re: Converting a float polynomial to integer polynomial

Hi Luka,

Wonderful, thanks a lot!

Apologies, I should have thought of that, I missed this command in the manual.

Jose
par jocaps
mer. sept. 19, 2018 7:56 am
Forum : Xcas - English
Sujet : Converting a float polynomial to integer polynomial
Réponses : 2
Vues : 329

Converting a float polynomial to integer polynomial

Hi, After some computations with algebraic numbers (as floats with high precision) I obtain a polynomial whose coefficients I know are integer but because the computations are done with floats, giac/xcas will show the coefficients with the decimals. I want to know what is the best way to convert thi...
par jocaps
ven. août 31, 2018 1:51 pm
Forum : Giac
Sujet : graph theory commands for Giac
Réponses : 198
Vues : 19183

Re: graph theory commands for Giac

I just want to congratulate lukamar for such hard work. This is amazing!! Has one the option to compile giac without Nauty or other graph theory libraries? I think having these options are really what makes giac stands out compared to other CAS. e.g. compiling with/without Pari, Cocoa etc. So one ca...
par jocaps
mar. juil. 17, 2018 10:23 pm
Forum : Giacpy
Sujet : linsolve with algebraic numbers and giacpy
Réponses : 1
Vues : 497

linsolve with algebraic numbers and giacpy

Hi, I am having a rather unusual output from linsolve when trying to solve a system of linear equation over algebraic numbers. The system that I have is defined by a matrix and I want to solve the kernel of this matrix. The matrix is rather long (so it is not a good idea to put it in this forum) but...
par jocaps
sam. juin 23, 2018 8:09 pm
Forum : Giac
Sujet : Citing Giac and Giacpy
Réponses : 2
Vues : 574

Citing Giac and Giacpy

Hi, Is there any guideline for citing giac and giacpy? I am trying to write a manuscript on sum of squares of rational polynomials (Sturmfel's problem) and need giac and giacpy for many of my computations. I would like to cite giac (and giacpy) for this. I understand Magma and GAP have their guideli...
par jocaps
sam. juin 23, 2018 7:05 pm
Forum : Giac
Sujet : graph theory commands for Giac
Réponses : 198
Vues : 19183

Re: graph theory commands for Giac

@lukamar Thank you for considering nauty implementation. I will certainly be very interested if this is done. Currently I am using nauty in C++ which is much faster than using it in XCas and giac. But for minor computations and computations involving multiple CAS and giacpy I will be interested in u...