# Drawing the parameters

Parameters can be plotted using a newly defined `drawParameters` instance, which shares the same 
prototype as the original method described in
[](#calibration_classes_functions_observations_calibration_classes_draw_parameter).

````{only} cpp
```cpp
void drawParameters(TString sTitre, const char *variable = "*", Option_t * option = "");
```
````

````{only} py
```python
drawParameters(sTitre, variable = "*", option = "")
```
````

It takes up to three arguments, two of which are optional:

1. **sTitre**: the title of the plot (an empty string is allowed);

2. **variable** (optional): a list of parameter names to be drawn, separated by colons ":". The default **"*"** draws all parameters;

3. **option** (optional): a list of options, separated by commas "," to adjust the plotting behavior:

    - **"nonewcanvas"**: draw on the current canvas (instead of creating a new one);

    - **"vertical"**: if multiple parameters are plotted, display them stacked vertically (one per row). By default, 
    plots are arranged horizontally, side by side.

    - **"apriori/aposteriori"**: draw only the *a priori* residuals or only the *a posteriori* residuals. If neither option is 
    specified, both are displayed;

    - **"transformed"**: this option specifies that the 
    transformed values should be used as the mean vector of the multivariate normal posterior 
    distribution.

The main difference compared to the standard `drawParameters` method in `TCalibration` is that the 
plotted object are analytical functions.

In addition to the parameters, the residuals can be plotted using the standard `drawResiduals` method,
which remains unchanged (see
[](#calibration_classes_functions_observations_calibration_classes_draw_residuals)).