# Implicit

When building a graph, the partition is part of the type of the graph. If a partition type is not provided by the user, a sensible default will be automatically used. For example, if a user uses stapl::digraph<int>, the partition is not specified and a block distribution will be used.

## Block Partition

A block partition is a simple partitioning scheme wherein the vertices are evenly distributed across the locations based on their numeric vertex descriptor. For vertices, each location will contain approximately vertices.

In the default implicit block partition, the graph's descriptor space will be partitioned across partitions, where the first vertices will be placed on location 0, the next descriptors will be on location 1 and so on.

For example, consider the following example graph () whose vertex descriptors span from 0 to 19:

If we partition the graph on four locations, it would look like this: