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# ccodefunctionstring

Converts a symbolic expression into a C-code function

[funstr, hdrstr] = ccodefunctionstring(symexpr, arglist) returns a string representing a C-code implementation of a symbolic expression symexpr. The C-code implementation has a signature of the form:

    void funname(double[][n_o] out, const double in1,

    const double* in2, const double[][n_i] in3);

depending on the number of inputs to the function as well as the dimensionality of the inputs (n_i) and the output (n_o). The whole C-code implementation is returned in funstr, while hdrstr contains just the signature ending with a semi-colon (for the use in header files).

## Options

'funname', name | Specify the name of the generated C-function. If this optional argument is omitted, the variable name of the first input argument is used, if possible.
'output', outVar | Defines the identifier of the output variable in the C-function.
'vars', varCells | The inputs to the C-code function must be defined as a cell array. The elements of this cell array contain the symbolic variables required to compute the output. The elements may be scalars, vectors or matrices symbolic variables. The C-function prototype will be composed accoringly as exemplified above.
'flag', sig | Specifies if function signature only is generated, default (false).

## Example

    % Create symbolic variables
    syms q1 q2 q3

    Q = [q1 q2 q3];
    % Create symbolic expression
    myrot = rotz(q3)*roty(q2)*rotx(q1)

    % Generate C-function string
    [funstr, hdrstr] = ccodefunctionstring(myrot,'output','foo', ...
    'vars',{Q},'funname','rotate_xyz')

## Notes

- The function wraps around the built-in Matlab function 'ccode'. It does not check for proper C syntax. You must take care of proper dimensionality of inputs and outputs with respect to your symbolic expression on your own. Otherwise the generated C-function may not compile as desired.

## Author

Joern Malzahn, (joern.malzahn@tu-dortmund.de)

## See also

ccode, matlabfunction

© 1990-2014 Peter Corke.