On Thu, Mar 25, 2010 at 9:20 AM, Freddie Witherden <fred...@witherden.org> wrote: > Hi all, > > On 24 Mar 2010, at 18:58, Ondrej Certik wrote: >> Here is one way (thanks again to Fernando for implementing the symarray!): >> >> In [1]: s = 17 >> >> In [2]: Bi1 = symarray(s, "B") >> >> In [3]: Ci1 = symarray(s, "C") >> >> In [4]: Add(*(Bi1*Ci1**4)) - S(1)/5 >> Out[4]: >> 4 4 4 4 4 4 4 >> -1/5 + B₀⋅C₀ + B₁⋅C₁ + B₁₀⋅C₁₀ + B₁₁⋅C₁₁ + B₁₂⋅C₁₂ + B₁₃⋅C₁₃ + B₁₄⋅C₁₄ >> >> 4 4 4 4 4 4 4 4 >> + B₁₅⋅C₁₅ + B₁₆⋅C₁₆ + B₂⋅C₂ + B₃⋅C₃ + B₄⋅C₄ + B₅⋅C₅ + B₆⋅C₆ + B₇⋅C₇ + >> >> 4 4 >> B₈⋅C₈ + B₉⋅C₉ > > How would you recommend handling multiple summations, such as > sum(sum(B[i]*A[i,j]*C[j],j,1,i),i,1,s)?
symarray allows multidimensional arrays, see symarray?, so you can try to use that. I don't have time now to do it myself. Ondrej -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sy...@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
