Prerequisites: Intel or AMD CPU with adcx/adox: i.e., Broadwell,
Skylake, or newer. Linux with standard development tools plus clang
plus valgrind.

To download and unpack the latest version:

wget -m https://ctidh.isogeny.org/high-ctidh-latest-version.txt
version=$(cat ctidh.isogeny.org/high-ctidh-latest-version.txt)
wget -m https://ctidh.isogeny.org/high-ctidh-$version.tar.gz
tar -xzf ctidh.isogeny.org/high-ctidh-$version.tar.gz
cd high-ctidh-$version

To compile, test for functionality, tune for multiplications, and tune
for cycles, for all selected sizes (511, 512, 1024, 2048):

make

This takes a while because of all the testing and tuning. Any test
failure will stop the build process. You can separately run

make generic # size-independent tests, 8.6 minutes
make 511 # size 511, 1.5 minutes
make 512 # size 512, 1.7 minutes
make 1024 # size 1024, 25 minutes
make 2048 # size 2048, 549 minutes

where the timings shown here are on a 3GHz Skylake core.

(Tuning for multiplications is machine-independent and can be
precomputed. Tuning for cycles can be precomputed per microarchitecture.
One can carry out both precomputations more efficiently by starting with
measurements of tree1, multiprod2, multiprod2_selfreciprocal,
multieval_precompute, and multieval_postcompute; the Python scripts
include a preliminary implementation of this for the multiplication
tuning, currently used only as a double-check.)

The functionality testing included in "make" does not include a
constant-time test. To run a constant-time test for all selected sizes:

make timecop # 25 minutes

For benchmarks regarding, e.g., size-511 code tuned for multiplications:

./bench511mults 16383 > bench511mults.out.16383

This runs a million experiments: more precisely, 16383 experiments for
each of 65 keys. This takes hours, and generates hundreds of megabytes
of data. Each measurement includes, for validation and separately for
the action, a "mulsq" count that includes both multiplications and
squarings, a "sq" count that includes only squarings, an "addsub"
count that includes additions and subtractions, and a cycle count (which
for multiplication-tuned code isn't far behind cycle-tuned code). The
action also shows "stattried" counts showing the number of times each
batch occurred publicly in an atomic block.

To analyze average costs and standard deviations:

./analyze-costs < bench511mults.out.16383 \
> bench511mults.out.16383.analyze-costs

Statistics are printed for each of the 65 keys separately, and
("total") for the all of the experiments together.

To analyze whether the "stattried" counts are as expected:

./analyze-pr < bench511mults.out.16383 \
> bench511mults.out.16383.analyze-pr

This prints, for each batch, 1−1/p times the number of times the batch
was tried divided by the batch bound, where p is the smallest prime in
the batch.

For various size-511 microbenchmarks:

./umults511
./ubench511

To select other CSIDH sizes and other CTIDH parameters (subject to
various undocumented restrictions), edit the table at the top of
autogen and run "./autogen; make".