Generating C and Fortran Expressions
If you have special-purpose programs written in C or Fortran, you may want to take formulas you have generated in Mathematica
and insert them into the source code of your programs. Mathematica
allows you to convert mathematical expressions into C and Fortran expressions.
|CForm[expr]||write out expr so it can be used in a C program|
|FortranForm[expr]||write out expr for Fortran|
|Export[file,expr,"C"]||write out a C function that computes expr|
Mathematica output for programming languages.
Here is an expression, written out in standard Mathematica
Here is the expression in Fortran form.
Here is the same expression in C form. Macros for objects like Power
are defined in the C header file mdefs.h that comes with most versions of Mathematica
If you want to generate a C version of an entire expression you can do this with Export
Here an entire C function is computed from a Mathematica CompiledFunction
One of the common motivations for converting Mathematica
expressions into C or Fortran is to try to make them faster to evaluate numerically. But the single most important reason that C and Fortran can potentially be more efficient than Mathematica
is that in these languages the user always specifies up front what type each variable will be—integer, real number, array, and so on.
makes such assumptions within Mathematica
, and generates highly efficient internal code. This can be made to run even faster by setting the CompilationTarget
Compiling Mathematica expressions.