ccode

C code representation of symbolic expression

Syntax

ccode(f)

ccode(f,Name,Value)

Description

ccode(f) returns C code for the symbolic expression f.

ccode(f,Name,Value) uses additional options specified by one or more Name,Value pair arguments.

Examples

Generate C Code from Symbolic Expression

Generate C code from the symbolic expression log(1+x).

syms x
f = log(1+x);
ccode(f)

ans =
    '  t0 = log(x+1.0);'

Generate C code for the 3-by-3 Hilbert matrix.

H = sym(hilb(3));
ccode(H)

ans =
    '  H[0][0] = 1.0;
       H[0][1] = 1.0/2.0;
       H[0][2] = 1.0/3.0;
       H[1][0] = 1.0/2.0;
       H[1][1] = 1.0/3.0;
       H[1][2] = 1.0/4.0;
       H[2][0] = 1.0/3.0;
       H[2][1] = 1.0/4.0;
       H[2][2] = 1.0/5.0;'

Initialize Arrays Efficiently

Because generated C code initializes only non-zero elements, you can efficiently initialize arrays by setting all elements to 0 directly in your C code. Then, use the generated C code to initialize only nonzero elements. This approach enables efficient initialization of matrices, especially sparse matrices.

Initialize the 3-by-3 identity matrix. First initialize the matrix with all elements set to 0 in your C code. Then use the generated C code to initialize the nonzero values.

I3 = sym(eye(3));
I3code = ccode(I3)

I3code =
    '  I3[0][0] = 1.0;
       I3[1][1] = 1.0;
       I3[2][2] = 1.0;'

Write Optimized C Code to File with Comments

Write C code to the file ccodetest.c by specifying the File option. When writing to a file, ccode optimizes the code by using intermediate variables named t0, t1, and so on.

syms x
f = diff(tan(x));
ccode(f,'File','ccodetest.c')

  t0 = pow(tan(x),2.0)+1.0;

Include the comment Version: 1.1 in the file by using the Comments option. ccode uses block comments.

ccode(f,'File','ccodetest.c','Comments','Version: 1.1')

  /*
  Version: 1.1
  */
  t0 = pow(tan(x),2.0)+1.0;

Input Arguments

f — Symbolic input

symbolic expression

Symbolic input, specified as a symbolic expression.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: ccode(x^2,'File','ccode.c','Comments','V1.2')

'File' — File to write to

character vector | string

File to write to, specified as a character vector or string. When writing to a file, ccode optimizes the code by using intermediate variables named t0, t1, and so on.

'Comments' — Comments to include in file header

character vector | cell array of character vectors | string vector

Comments to include in the file header, specified as a character vector, cell array of character vectors, or string vector. Because ccode uses block comments, the comments must not contain /* or */.

Tips

• To generate optimized C or C++ code from a symbolic expression, especially for a large expression, you can use the MATLAB^® Coder™ app instead of using the ccode function. This way, the generated code is better integrated into the MATLAB ecosystem. First, convert the symbolic expression to a deployable MATLAB function using matlabFunction. Then, generate C or C++ code from the MATLAB function using the MATLAB Coder app. For an example, see Generate C Code from Symbolic Expressions Using the MATLAB Coder App.