#!/usr/bin/env python3 """Reproduce any row of `pphilip/analog-circuits-sky130` with ngspice. Usage ----- python example_simulate.py # first converged row of train python example_simulate.py --split test --row 42 python example_simulate.py --circuit-id analoggym_amp_yan_az_pin_3_s015 python example_simulate.py --row 0 --print-spice # dump the reconstructed SPICE Every row of the `with_testbench` config carries the exact, ngspice-ready SPICE that produced its `metrics`. Reproducing a row is: 1. Load the row. 2. Substitute `{{SKY130_LIB}}` with your local SKY130 `.lib` path. 3. Run ngspice on the result. 4. Parse the `.meas` output. Prerequisites ------------- pip install datasets # Install ngspice (v46+): # brew install ngspice (macOS) # apt install ngspice (Debian/Ubuntu) # (or build from source: http://ngspice.sourceforge.net/) # Install the SkyWater SKY130 PDK (Apache 2.0): pip install volare && volare fetch --pdk sky130 # Point SKY130_LIB at the combined/continuous lib: export SKY130_LIB="$(volare show sky130)/sky130A/libs.tech/combined/continuous/sky130.lib.spice" """ from __future__ import annotations import argparse import json import os import shutil import subprocess import sys import tempfile from pathlib import Path # --------------------------------------------------------------------------- # Run ngspice + parse .meas output # --------------------------------------------------------------------------- def run_ngspice(spice_text: str) -> tuple[dict[str, float], str]: """Run ngspice in batch mode. Returns (parsed_metrics, raw_log). ngspice's `ngbehavior=hs` mode lowercases every token, so `.meas` labels come back as `dc_gain_db` even if the SPICE source wrote `dc_gain_dB`. Parsing is case-insensitive. """ if shutil.which("ngspice") is None: raise RuntimeError( "ngspice not found on PATH. Install it (see prerequisites above)." ) with tempfile.TemporaryDirectory() as d: tb = Path(d) / "tb.spice" tb.write_text(spice_text) r = subprocess.run( ["ngspice", "-b", str(tb)], capture_output=True, text=True, timeout=60, ) log = r.stdout + r.stderr # `.meas` output looks like: dc_gain_db = -3.07410e+01 at= 1.00000e+00 metrics: dict[str, float] = {} for line in log.splitlines(): parts = line.strip().split("=", 1) if len(parts) != 2: continue key = parts[0].strip().lower() if not key or " " in key: continue # Take the first numeric token after `=` for tok in parts[1].split(): try: metrics[key] = float(tok) break except ValueError: continue return metrics, log def first_reproducible_row(ds) -> int: """Return the index of the first converged row with a non-empty testbench_spice. `failed` split rows can still carry a testbench_spice (the sim was attempted but didn't converge), so testbench-presence alone isn't enough — we also require `converged=True` so the shipped `metrics` are meaningful. """ for i in range(len(ds)): row = ds[i] if row.get("converged") and row.get("testbench_spice"): return i raise RuntimeError("no converged row with testbench_spice found in this split") def main() -> int: ap = argparse.ArgumentParser(description=__doc__) ap.add_argument("--split", default="train", choices=["train", "validation", "test", "failed"]) ap.add_argument("--row", type=int, default=None, help="Row index within the split (default: first usable row)") ap.add_argument("--circuit-id", default=None, help="Alternative to --row: look up by exact circuit_id") ap.add_argument("--print-spice", action="store_true", help="Print the reconstructed SPICE and exit without running") args = ap.parse_args() from datasets import load_dataset print(f"Loading pphilip/analog-circuits-sky130 (config: with_testbench, split: {args.split})…") ds = load_dataset( "pphilip/analog-circuits-sky130", "with_testbench", split=args.split, ) if args.circuit_id is not None: idx = None for i, r in enumerate(ds): if r["circuit_id"] == args.circuit_id: idx = i break if idx is None: print(f"circuit_id {args.circuit_id!r} not in split {args.split!r}", file=sys.stderr) return 1 elif args.row is not None: if not 0 <= args.row < len(ds): print(f"--row {args.row} out of range (split has {len(ds)} rows)", file=sys.stderr) return 1 idx = args.row else: idx = first_reproducible_row(ds) row = ds[idx] shipped = json.loads(row["metrics"]) if row["metrics"] else {} spice = row["testbench_spice"] print(f" circuit_id: {row['circuit_id']}") print(f" topology: {row['topology']} (source: {row['source_dataset']})") print(f" shipped metric: dc_gain_dB = {shipped.get('dc_gain_dB', 'n/a')} dB") if not spice: print("\n ERROR: this row has no testbench_spice (failed-build case).", file=sys.stderr) return 1 if args.print_spice: # Show the SPICE verbatim including the {{SKY130_LIB}} placeholder — # this path doesn't run ngspice, so a local PDK isn't required. print("\n--- reconstructed SPICE ---") print(spice) return 0 sky130_lib = os.environ.get("SKY130_LIB") if not sky130_lib or not Path(sky130_lib).exists(): print( "ERROR: SKY130_LIB env var not set or doesn't point to a valid file.\n" "Install the PDK: `pip install volare && volare fetch --pdk sky130`\n" "Then: `export SKY130_LIB=` " "(combined/continuous variant).", file=sys.stderr, ) return 2 # Swap the portability placeholder for the user's local PDK path. spice = spice.replace("{{SKY130_LIB}}", sky130_lib) print("\nRunning ngspice…") try: metrics, log = run_ngspice(spice) except RuntimeError as e: print(f"ERROR: {e}", file=sys.stderr) return 3 reproduced = metrics.get("dc_gain_db") # ngspice lowercases output keys print(f" reproduced: dc_gain_dB = {reproduced} dB") if reproduced is not None and "dc_gain_dB" in shipped: delta = abs(reproduced - shipped["dc_gain_dB"]) tag = "✓ bit-exact" if delta < 1e-3 else ("~ within 0.1 dB" if delta < 0.1 else "✗ mismatch") print(f" delta: {delta:.6f} dB {tag}") return 0 if __name__ == "__main__": sys.exit(main())