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loop problems

  • To: mathgroup at smc.vnet.net
  • Subject: [mg13341] loop problems
  • From: "Daniel R. Cohen" <cohend at uansv5.vanderbilt.edu>
  • Date: Mon, 20 Jul 1998 02:49:58 -0400
  • Organization: Vanderbilt Institute of Public Policy Studies
  • Sender: owner-wri-mathgroup at wolfram.com

[Contact the author to obtain the notebook - moderator]

I have two pieces of a larger problem here that are stopping the program
from working, but I can't figure out what I've done wrong.

I have tried to separate out what appear to be the two problems
hindering evaluation of the larger expression. (In case it helps, I
have again attached the entire program along with this message.) If
anyone can help me with this, I could really use assistance.

Perhaps it's as simple as the wrong phrasing of the indices/functions,
but I'm just not sure what to do about it.

1. Even if I give Mathematica a value for each of the G[] matrices,
which are all (3x3) matrices, and give it a value for t, it still is
unable to do the following expression.


\[Sum]\+\(i = \((t + 1)\)\)\%\(T + 1\)\((
                              \[Product]\+\(j = \(-i\)\)\%\(-\((t +
1)\)\)G[
                                  Abs[j]])\)]


2. In addition, I have some nested loops within the larger problem that
do not work. Following is an abbreviated version. As before, I have
given the values for T, F[T+1], and G[T+1], as well as a formula
related each successive G[t] to each F[t], which I've re-written just
above the problematic loop. The rest should be taken care of in the
iteration, as far as finding the successive values for F[t]. (A and B
are given also.)

MatrixForm[G[t_]=A+B.F[t]];


For[t = T, t > 0, \n\t
      Print[\tMatrixForm[
          F[t] = \[Sum]\+\(i = \((t + 1)\)\)\%\(T + 1\)\((
                            F[i] .
                              \((\[Product]\+\(j = \(-i\)\)\%\(-
                                      \((t + 1)\)\)G[Abs[j]])\)
 ]],t--]




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