Examples miter-based sequential equivalence checking using a variety
of tools.

Notes
=====

- iimc utilizes multiple cores.
- the abc 'pdr' command does IC3.
- the abc 'dprove' command does SEC of a miter.
- the abc 'dsec' command does *not* operate on miters. If you give it
  a single input circuit it will compare that circuit to itself,
  always returning "equivalent"!
- the abc 'simsec' command always segfaults, or complains that the
  input is not a valid miter.

Timing
======

Timing info for successful verifications.

Exponentiation loops
--------------------

The linearly- and log-many-multiplications exponentiation
examples. All of these runs are successful, with the prover returning
"equivalent".

Conclusion: iimc is fast on this example!

    abc -c 'read tmp/mitered-exp.4.4.aig; pdr'  1.00s user 0.02s system 99% cpu 1.026 total
    abc -c 'read tmp/mitered-exp.6.6.aig; pdr'  1001.56s user 32.41s system 100% cpu 17:13.96 total

    abc -c 'read tmp/mitered-exp.4.4.aig; dprove'  1.57s user 0.04s system 99% cpu 1.608 total
    abc -c 'read tmp/mitered-exp.6.6.aig; dprove'  436.32s user 4.20s system 100% cpu 7:20.51 total

    iimc tmp/mitered-exp.4.4.aig  0.36s user 0.04s system 260% cpu 0.153 total
    iimc tmp/mitered-exp.6.6.aig  5.07s user 0.10s system 352% cpu 1.468 total
    iimc tmp/mitered-exp.8.8.aig  198.91s user 1.14s system 375% cpu 53.282 total
    nice iimc tmp/mitered-exp.8.8.aig  214.46s user 1.18s system 387% cpu 55.681 total
    nice iimc tmp/mitered-exp.10.10.aig  18535.06s user 30.12s system 385% cpu 1:20:10.64 total

    tip tmp/mitered-exp.4.4.aig  0.11s user 0.00s system 99% cpu 0.113 total
    tip tmp/mitered-exp.6.6.aig  986.17s user 2.32s system 99% cpu 16:28.51 total

    IC3 < tmp/mitered-exp.4.4.aig  0.52s user 0.00s system 99% cpu 0.520 total
    IC3 < tmp/mitered-exp.6.6.aig  283.36s user 0.73s system 99% cpu 4:44.09 total


Weird progression of ABC results using 'dsec':

    $ for n in 4 6 8 10; do
        eval time abc -c "'dsec tmp/exp-ref.$n.$n.aig tmp/exp-opt.$n.$n.aig'"
      done 2>&1 | tee dsec.out

    ABC command line: "dsec tmp/exp-ref.4.4.aig tmp/exp-opt.4.4.aig".

    Networks are equivalent.   Time =     1.36 sec
    abc -c 'dsec tmp/exp-ref.4.4.aig tmp/exp-opt.4.4.aig'  1.32s user 0.07s system 99% cpu 1.396 total


    ABC command line: "dsec tmp/exp-ref.6.6.aig tmp/exp-opt.6.6.aig".

    The miter is proved unreachable after 23 iterations.  Time =     0.67 sec
    Networks are equivalent.   Time =    97.46 sec
    abc -c 'dsec tmp/exp-ref.6.6.aig tmp/exp-opt.6.6.aig'  95.66s user 1.84s system 100% cpu 1:37.50 total


    ABC command line: "dsec tmp/exp-ref.8.8.aig tmp/exp-opt.8.8.aig".

    BDDs blew up during image computation.  Time =     2.40 sec
    Reached timeout (60 seconds).
    Networks are UNDECIDED.   Time =   369.04 sec
    The unsolved reduced miter is written into file "sm01.aig".
    abc -c 'dsec tmp/exp-ref.8.8.aig tmp/exp-opt.8.8.aig'  361.95s user 7.14s system 99% cpu 6:09.11 total


    ABC command line: "dsec tmp/exp-ref.10.10.aig tmp/exp-opt.10.10.aig".

    The number of intermediate BDD nodes exceeded the limit (50000).
    Reached timeout (60 seconds).
    Networks are UNDECIDED.   Time =   150.12 sec
    The unsolved reduced miter is written into file "sm01.aig".
    abc -c 'dsec tmp/exp-ref.10.10.aig tmp/exp-opt.10.10.aig'  146.25s user 3.92s system 99% cpu 2:30.18 total
