Hi Olfa,
On Wed, Dec 24, 2008 at 11:05 PM, olfa <[email protected]> wrote:
>
> Mr Ondrej, here a full example (wrote in mathematica) of what I want
> to do. Unfortunately, it doesn't work in mathematica (especially for
> nesting function and for lists) and that's why I want to know if sympy
> could help me; It will be really great!
sorry for my late reply, I am really busy now moving to Nevada.
>
> Reduce[ {
> i<=iP,
> j>=jP,
> 1*j+1*i==1*jP+1*iP,
> mP==Nest[Rest,m,iP-i],
> i+Length[m]==iP+Length[mP],
> 1*n-4*i==1*nP-4*iP,
> 4*i-1*n==4*iP-1*nP,
> tt/3^(i/1)==ttP/3^(iP/1),
> mP==Nest[Rest,m,j-jP],
> j-Length[m]==jP-Length[mP],
> 4*j+1*n==4*jP+1*nP,
> Nest[f,v,j]==Nest[f,vP,jP],
> tt/3^(j/-1)==ttP/3^(jP/-1),
> Join[l,m]==Join[lP,mP],
> t-c*n*(n-4)/(2*4)==tP-c*nP*(nP-4)/(2*4),
> tt/3^(n/4)==ttP/3^(nP/4),
> vv+7*tt/(1-3)==vvP+7*ttP/(1-3),
> x+Sum[A[k],{k,i,N}]==xP+Sum[A[k],{k,iP,N}],
> y+Sum[B[k],{k,1,j}]==yP+Sum[B[k],{k,1,jP}],
> w+Sum[Nest[f,v,k],{k,1,j}]==wP+Sum[Nest[f,vP,k],{k,1,jP}],
> (iP==20+1)},
> {iP, jP, lP, mP, nP, tP, ttP, vP, vvP, wP, xP, yP},Backsubstitution-
>>True]
>
>
> here: arrays are A and B and lists are l,m,lP and mP.
I am a bit confused by this, but as I understand, you have a set of
equations of a type:
tt/3^(i/1)==ttP/3^(iP/1)
1*j+1*i==1*jP+1*iP
This equation seems pretty tough:
Nest[f,v,j]==Nest[f,vP,jP]
looking here:
http://reference.wolfram.com/mathematica/ref/Nest.html
does the left hand side mean f(f(f(...f(v))) where the nesting is
done "j" times?
Then you also seem to have couple of inequalities, of the type:
i<=iP
And you are interested in solving all those equations and
inequalities, am I right?
As I said in my previous email, you can solve sets of equations in
sympy -- but the Nest operator is not yet implemented and also the
solver() is not yet clever about Sums too much. So I am afraid it
still needs substantial work.
How did you get these equations? What kind of problem is it, that the
formulation looks like that?
Ondrej
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