---
myst:
    substitutions:
        subject: "This part"
        provision: ""
        linear_regression: "{ref}`models_linear_regression`"
---
```{include} /../core/modeler/introduction.md
```

```{include} /../core/modeler/introduction/discussion.md
```

This ensemble (of size $n_S$) can be written as
```{math}
\mathcal{L} = \{(\mathbf{x}^i, y^i), i=1, \ldots, n_S\}
```
where $\mathbf{x}^i$ is the i-th input vector which can be written as
$\mathbf{x}^i=(x^i_1\, \ldots\, x^i_{n_X})$ and the output $y^i =
y(\mathbf{x}^i)$.

```{include} /../core/modeler/introduction/models.md
```

```{toctree}
introduction/fitting_strategy
```