subst('pwr,"^",expr)
On 2010-08-04, Sheldon Newhouse <sen1 at math.msu.edu> wrote:
> Hello,
> I work in a unix environment (Fedora Core 12) and I want to make use
> of an external program in conjunction with maxima.
>
> The external program does not accept the character '^' for powers.
>
> It has a function "pwr(x,n)" which outputs the same as maxima's
> "x^n" It also uses " := " as the assignment operator
> instead of maxima's " : ".
>
> So, basically, I want to take some maxima input saved into a file
> (e.g. with the stringout command) and import it to this external program.
>
> Thus, suppose that I have the following maxima commands
>
> (%i2) p: x^3*sin(x^4-1)^2 - x^2 + 1.2;
>
> (%o2) x^3*sin(x^4-1)^2-x^2+1.2
> (%i3) stringout("data_3", p);
>
> (%o3) "/home/sen/Current_Work/VI_prac/data_3"
> (%i4) system("cat data_3");
>
> x^3*sin(x^4-1)^2-x^2+1.2;
>
> (%o4) ?\#\<process\ 22543\ \:EXITED\>
>
> Thus, we have the string
> x^3*sin(x^4-1)^2-x^2+1.2;
>
> in the file "data_3".
>
> I want to change the output string to
>
> pwr(x,3)*pwr(sin(pwr(x,4)-1),2 - pwr(x,2) + 1.2;
>
> for input into the other program.
>
> Of course, for a given expression as above, I could simply use a text
> editor to modify it. But, I want a function which will transform any
> maxima polynomial expression in the variable x and compositions of
> intrinsic functions (sin, cos, exp, log, etc) with other polynomials
> into another expression in which all powers are changed into the pwr
> function.
>
> Any ideas would be appreciated.
>
> TIA,
> -sen
>
>
>
>
>
>
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