vyges-gpl

Global placement. The engine builds the placer's view of the design — instances, nets, pins, regions, the sites a placement may not use — runs the initial placement (rounds of a bound-to-bound net model solved by BiCGSTAB, in exactly the arithmetic order of the reference solver) and then the Nesterov electrostatic placement, so every coordinate matches bit for bit.

vyges install physical
vyges physical gpl global_placement job.json
vyges physical gpl --describe

Documentation: docs/src/gpl.md (an mdBook; mdbook build docs), with the CLI reference.

The job

{
  "steps": [
    { "cmd": "read_db",          "args": ["floorplan.odb"] },
    { "cmd": "global_placement", "args": ["-skip_nesterov_place"] }
  ],
  "write_def": "placed.def"
}

The report carries the command's own lines in order — the placer's header (core, site, instance and pin counts, areas, utilisation) and each [InitialPlace] round with its residual and HPWL — and a status:

{ "tool": "vyges-gpl", "status": "placed", "insts": 294, "nets": 364, "pins": 1122,
  "lines": [ "[INFO GPL-0001] ---- Initialize GPL Main Data Structures", … ] }

What is modelled

• the placer's construction: instances (fixed ones snapped outward to whole sites, padding), the pin-density area adjustment, signal and clock nets with their pins, regions, dummy instances over unusable sites;
• the initial placement: start points, the bound-to-bound matrix for x and y, the solver with its restart, the clamp to the core and region, the database written as the reference writes it;
• the Nesterov (electrostatic) placement: fillers, the pre-placement perturbation, the bin grid, the DCT density field, the weighted-average wirelength gradient, the accelerated descent with back-tracking and the divergence revert — over the top level and every region group, each region its own density field;
• incremental placement: the instances already placed held where they are while the new ones settle, then everything released for a second pass;
• placement clusters: a group of instances moved as one cell, sized to their total area;
• routability-driven placement: the routability snapshot, then congestion measured on the global router's grid — by RUDY (each net's wire density spread over the tiles its box covers) or by the global router's own usage (-routability_use_grt); over the target, the cells in congested tiles inflated within the inflation budget, fillers removed for the area, the nets feeding those tiles reweighted, and the placement re-run from the snapshot — until the congestion meets the target, stops improving or the budget is spent, when the best pass is restored;
• concurrent IO placement (-place_ios): the movable ports placed with the cells, each held to its legal locus on the die perimeter (excluded regions removed, its own constraint region, its mirror partner's reflection) or inside its top-layer box, then written as pins.

Refused rather than guessed: -timing_driven, -virtual_cts.

Build

Check out vyges-tools/opendb, opendb-lib, loom and layout beside this repository (see .github/workflows/ci.yml), then:

cargo build --release --features cli
cargo test  --release --features cli

Without --features cli the library builds with no C++ dependency.

Licensed under Apache-2.0.