Exercise Template

# Exercise 1 - Name of the exercise

|                         |                    |
| -----------------------:| ------------------ |
|   Turnin directory :    |  ex00              |
|   Files to turn in :    |  *.py              |
|   Forbidden function :  |  None              |
|   Remarks :             |  n/a               |

**Objective(s):**
Description of the objective(s) of the exercise.

**Instructions:**
In the *.py file create the following function(s) as per the instruction below:
```python
def func(param_name):
    """
    Description of what the function is doing with the parameters.
    :param param_type param_name:
    :return return_type: short description of the return values according to the correct (or not) inputs.
    """
```

**Examples:**
```python
print("Code example")
```

Objective(s):

If a formula is re-implemented, use the following template:

You must implement the following formula as a function: 
$$
formula as latex
$$
where:
- $formula_param1$ is ...
- $formula_param2$ is ...

Instructions:

Inputs:

• vectors or matrices of the functions must be numpy.ndarray
• constant must be float

Outputs:

• vectors or matrices of the functions must be numpy.ndarray
• constant must be float
• if inputs are invalid, must return None

Examples:

• At least 2 examples for each functions. If its behavior is complex do not hesitate to put more!
• Do not show examples of invalid inputs.
• Any time it is possible, show the official result (with Numpy, Sklearn) after the function example to show that it mimics properly the original one.