# Matrix Sampler¶

Samples a relation matrix.

## Signals¶

**Inputs**:

**Data**

Data set.

**Outputs**:

**In-sample Data**Selected data.

**Out-of-the-sample Data**Remaining data.

## Description¶

This widget samples the input data and sends both the sampled and the remaining data to the output. It is useful for evaluating the performance of recommendation systems.

- Select the desired
*sampling method*:**rows**(randomly samples entire matrix rows)**columns**(randomly samples entire matrix columns)**rows and columns**(samples from the entire matrix)**entries**(randomly samples individual matrix elements)

- Select the proportion of the data you want at the output.
- Press
**Apply**to commit the changes.

## Example¶

**Matrix Sampler** widget samples data into two subsets: in-sample and
out-of-the-sample data. This is useful if you want to check the accuracy
of matrix reconstruction with **Completion Scoring**. Feed in-sample
data into the **Fusion Graph** to reconstruct the matrix and then
compare the results with out-of-the-sample data.