As part of some maxima ramblings, a little script to take a fortan expression, which is used to generate efficiently computed list of function values.

A possible use for this is to generate heavy graphs from mathematica expressions, which can be converted into fortran expressions with the fortran command:

fortran(diff(sin(x)/x,x)); COS(x)/x-SIN(x)/x**2

The idea is to have a easy to use C program call a little fortran subroutine with the fortran code in it, and that the whole operation is done by a tcl proc, which also takes care of the combined compilation of the fortran and C function value loop code, and the exec of the resulting executable:

# Feed this Tcl proc a fortran expression proc formake {e} { global f set t " subroutine sayhello(x,r) real a,r r = " append t $e append t " return end

"

set f [open sub.f w] puts $f $t close $f exec gcc -o fm sub.f main.c -lm return [exec fm] }

This, or an adapted, C program is needed in the current directory:

/* This is file: main.c */ #include<stdio.h> #include<math.h> extern void sayhello_(float *, float *); int main(argc, argv) int argc; char *argv[]; { float in, out; float x, start, stop, incr; if (argc == 1) { start = -10.0; stop = 10.0; incr = 2.0; } else exit(-1); for (x=start; x<=stop; x+=incr) { in = x; sayhello_(&in,&out); printf("%f %f\n", x, (float) out); } return(0); }

Calling the formake routine in this case returns a formatted list of 21 X Y values, but it could return more. Of course braces could be added to automatically create a Tcl list as result.

There is nothing against using these methods in Bwise blocks.