# Assigning some results after a solve procedure to a matrix

Posted 8 years ago
2017 Views
|
0 Replies
|
0 Total Likes
|
 Hello,I have a matrix M[3,3]. After a solve procedure, I obtained these results. {{M[1, 2] -> Cos[?[t]], M[1, 3] -> 0, M[2, 3] -> 0, Cos[?[t]] -> M[3, 1], M[3, 2] -> 0, M[3, 3] -> 1, M[2, 1] -> -Cos[?[t]] Sin[?[t]], M[2, 2] -> Sin[?[t]], M[1, 1] -> Sin[?[t]] Sin[?[t]]}} I would like to assign the all the parameters M[1,1], M[1,2], ... to the coefficients of my matrix.Here my code : Thread[Array[M, {3, 3}].? == ?] {{M[1, 2] -> Cos[?[t]], M[1, 3] -> 0, M[2, 3] -> 0, Cos[?[t]] -> M[3, 1], M[3, 2] -> 0, M[3, 3] -> 1, M[2, 1] -> -Cos[?[t]] Sin[?[t]], M[2, 2] -> Sin[?[t]], M[1, 1] -> Sin[?[t]] Sin[?[t]]}} soln = SolveAlways[%, ?] {{M[1, 2] -> Cos[?[t]], M[1, 3] -> 0, M[2, 3] -> 0, Cos[?[t]] -> M[3, 1], M[3, 2] -> 0, M[3, 3] -> 1, M[2, 1] -> -Cos[?[t]] Sin[?[t]], M[2, 2] -> Sin[?[t]], M[1, 1] -> Sin[?[t]] Sin[?[t]]}} matrix = Array[M, {3, 3}] {{M[1, 1], M[1, 2], M[1, 3]}, {M[2, 1], M[2, 2], M[2, 3]}, {M[3, 1], M[3, 2], M[3, 3]}} M = matrix /. soln Here the coefficients are not well assigned as you could see : Hold[{{Sin[?[t]] Sin[?[t]], Cos[?[t]], 0}, {-Cos[?[t]] Sin[?[t]], Sin[?[t]], 0}, {M[3, 1], 0, 1}}] How can I assign the different coefficients obtained in order to be able to evaluate the matrix M ?I use Mathematica 10, so may be the Values function can be useful but I didn't manage to use it correctly for this purpose for the moment.In fact, the function SolveAlways give me some rules but sometimes, these rules are not in the good direction (Cos[?[t]] -> M[3, 1]). Consequently, I believe that it is the cause of the difficulty I meet link to the assignments of the coefficients of the matrix.Thanks a lot for your help