threABC

Introduction

• Threshold logic collapse operation and verification within ABC
• Primary developer: Nian-Ze Lee from National Taiwan University
• C implementation of algorithms proposed in Analytic Approaches to the Collapse Operation and Equivalence Verification of Threshold Logic Circuits
• Algorithms and codes for threshold logic technology mapping proposed in Threshold Logic Synthesis Based on Cut Pruning by Augusto Neutzling et al.
• Reference: Nian-Ze Lee, Hao-Yuan Kuo, Yi-Hsiang Lai, Jie-Hong R. Jiang: Analytic approaches to the collapse operation and equivalence verification of threshold logic circuits. ICCAD 2016: 5

Contents

1. Installation
2. Commands
3. Examples
4. Experiments
5. Contact

Installation

Type make to complie and the executable file is bin/abc

make

The source code has been compiled successfully with GCC_VERSION=8.2.0 under CentOS 7.3.1611/Ubuntu 18.04 LTS

Commands:

I/O:

• read_th (alias rt): read a TL circuit (TLC) file in the .th format (POs must be buffered)
• write_th (alias wt): write the current TLC out in the .th format
• print_th (alias pt): print the network statistics of the current TLC

Synthesis:

• aig2th (alias a2t): convert an AIG circuit to a TLC by replacing AIG nodes with TL gates (TLGs)
• merge_th (alias mt): the proposed collapsing-based TLC synthesis
• th2blif (alias t2b): convert a TLC to a blif file by transforming a threshold gate to a truth table

Verification:

• th2mux (alias t2m): convert a TLC to an AIG circuit by expanding a TLG to a MUX tree
• thverify (alias tvr): write a CNF/PB file for the equivalence checking of two TLCs
• thpg (alias tp): write a PB file for the output satisfiability of a TLC with PG encoding

Misc:

• test_th: testing playground
• profile_th: print detailed collapse information

Outdated (only for documentation):

• PB_th: eq check between pNtkCur and current_TList by PB
• CNF_th: eq check between pNtkCur and current_TList by CNF
• NZ: eq check between cut_TList and current_TList by PB
• OAO: eq check between cut_TList and current_TList by CNF

Examples

1. Collapse an AIG circuit iteratively with a fanout bound = 100 (aig_syn is defined in file abc.rc)

abc 01> r exp_TCAD/collapse/benchmark/iscas_itc/s38417.blif
abc 02> aig_syn
abc 03> mt -B 100
abc 04> pt
abc 05> q

2. Collapse a synthesized TLC iteratively with a fanout bound = 100 (tl_syn is defined in file abc.rc)

abc 01> r exp_TCAD/collapse/benchmark/iscas_itc/s38417.blif
abc 02> tl_syn
abc 03> wt s38417_before_clp.th
abc 04> mt -B 100
abc 05> pt
abc 06> wt s38417_after_clp.th
abc 07> q

3. Verify equivalence using the TL-to-MUX translation and ABC command cec (continued from the above example)

abc 01> rt s38417_before_clp.th
abc 02> t2m
abc 03> w s38417_before_clp.aig
abc 04> rt s38417_after_clp.th
abc 05> t2m
abc 06> w s38417_after_clp.aig
abc 07> cec s38417_before_clp.aig s38417_after_clp.aig
abc 08> q

4. Verify equivalence using the TL-to-PB translation and minisat+ (continued from the above example)

abc 01> tvr s38417_before_clp.th s38417_after_clp.th
abc 02> q
$ bin/minisat+ compTH.opb

5. Verify equivalence using the TL-to-CNF translation and minisat (continued from the above example)

abc 01> tvr -V 1 s38417_before_clp.th s38417_after_clp.th
abc 02> q
$ bin/minisat compTH.dimacs

6. Check the output satisfiability of a TLC using the PB-based method with PG encoding (pg_and is defined in file abc.rc)

abc 01> r exp_TCAD/pg_encoding/benchmark/b14.blif
abc 02> pg_and
abc 03> q
$ bin/minisat+ no_pg.opb
$ bin/minisat+ pg.opb

Experiments

Directory exp_TCAD contains all benchmarks, scripts, log files, and data in the experiments. Specifically:

1. Sub-directory collapse is for the collapsing-based synthesis experiments
2. Sub-directory eqcheck is for the verification experiments between TLCs before and after collapsing
3. Sub-directory pg_encoding is for the PG encoding experiments
4. Sub-directory high_fanin is for the translation scalability experiments
5. Sub-directory dnn_mnist is for the activation-binarized neural networks experiments

Suggestions, Questions, Bugs, etc

You are welcome to create an issue to make suggestions, ask questions, or report bugs, etc.

Contact

Please send an email to Nian-Ze Lee ([email protected]) if there is any problem.