# `TCIntEval` and `TCJitEval`

These classes are generaly used when you use the cling root interpreter with Uranie. So they are not 
detailed here. Their documentation can be find in the C++ version of this documentation, but their 
uses are very similar to a `TPythonEval` class.

Using C function in python can be done with the ROOT cling interpreter and the `TCIntEval`. Suppose 
you have a C rosenbrock function defined in the `UserFunctions.C` file as follow.

```cpp
void rosenbrock(double *in, double *out)
{
    double x, y, d1, d2;
    x = in[0]; y = in[1];
    d1 = (1-x);
    d2 = (y-x*x);
    out[0] = d1*d1 + d2*d2;
}
```

To use this function in Uranie, you need to load the script, and define the `TCIntEVal` (a 
`TCJitEval` does not work in python interpreter) 

```python
ROOT.gROOT.LoadMacro("UserFunctions.C")
fun = Relauncher.TCIntEval("rosenbrock")
```

It is also possible to simply use a C++ function in python, through the ROOT cling interpreter out 
of the {{Relaun}} paradigm (for single-purpose estimation for instance). This discussion is already 
covered in [](#overview_python_handbook_py_cpp_function).