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Re: Export a matrix in C form

  • To: mathgroup at smc.vnet.net
  • Subject: [mg89881] Re: Export a matrix in C form
  • From: roby.nowak at gmail.com
  • Date: Tue, 24 Jun 2008 03:19:59 -0400 (EDT)
  • References: <g3ihro$fft$1@smc.vnet.net>

On 21 Jun., 11:32, Pavel Balaz <pavel.ba... at gmail.com> wrote:
> Hi,
>
> I have a big matrix in Mathematica with elements given as function of
> several parameters. I would like to export this matrix to C/C++ in
> this general form. However, if I use CForm[], I obtain something like
> List(List(cos(x),sin(y), ...), List(exp(x*y), ...), ...)
> I have never seen such C/C++ code :-(
> It is possible to save the matrix element to a single file containing
> definitions all matrix elements in the form
> double M[16][16];
> M[0][0]=cos(x);
> M[0][1]=sin(x);
> ...
>
> Thank you very much.

Hi,

love it or hate it:

{{Cos[x], Sin[x]}, {-Sin[x], Cos[x]}}
% // # /. {Cos[x_] -> "cos(x)", Sin[x_] -> "sin(x)"} &
% // MapIndexed[
     "M[" <> ToString[First@#2 - 1] <> "][" <> ToString[Last@#2 - 1]
<>
        "]=" <>
       ToString@#1 <> ";\n" &, #, {2}] & //
  Flatten // StringJoin @@ # &




{{Cos[x], Sin[x]}, {-Sin[x], Cos[x]}}

{{"cos(x)", "sin(x)"}, {-"sin(x)", "cos(x)"}}

M[0][0]=cos(x);
M[0][1]=sin(x);
M[1][0]=-sin(x);
M[1][1]=cos(x);



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