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

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

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

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;'

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.

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

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

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;

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

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