matchpack

The goal of this module is to find the best schematic layout for a set of SchematicChips and SchematicGroups containing SchematicPins connected to each other with SchematicTraces

To do this, we use a series of solvers that are run in a pipeline. Each solver is responsible for a specific piece of input preprocessing or calculation.

This is roughly the hierarchy of solvers:

LayoutPipelineSolver: Runs pipeline
↳ ChipPartitionsSolver: Creates partitions (small subset groups) surrounding complex chips
  ↳ SingleChipPartitionSolver: Creates a single partition for a single chip
↳ PartitionPackingSolver: Packs the laid out chip partitions into a single layout

Implementation Notes

• There is the concept of a "weak" and "strong" connection between pins. A "strong" connection is one where a pin is directly assigned to another pin. A "weak" connection is generally a pin assigned to a net like "GND" or "VCC". Strong connections are important for layout but weak connections often determine orientation of passives (e.g. a capacitor is "facing up" to VCC but "facing down" to GND)
• Often there are pre-laid-out designs that are passed in. This is represented by a SchematicGroup. We don't lay out anything inside of these groups but the inner pins are still used to compute a good packing