P_a = P.subs(dict(zip(a, val_a))) returns
(0.450033195586719*x + 0.829322314411828)/(x**3*b[2, 0] + x**2*b[1, 0] + x*b [0, 0] + 1) You need to substitute individual MatrixElement objects like a[0], not the MatrixSymbol itself (which isn't even present in the expression P). -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To post to this group, send email to sympy@googlegroups.com. Visit this group at https://groups.google.com/group/sympy. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/1402e58d-b081-4912-8e11-0ea200bef3f6%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
