Getting started

Requirements

• GCC 7.5
• cmake 3.16

For Ubuntu 18.04 LTS the following commands installs the requirements:

sudo apt install --no-install-recommends git cmake make g++ mpi-default-dev libprotobuf-dev libboost-dev libboost-program-options-dev libboost-filesystem-dev libboost-iostreams-dev libboost-date-time-dev protobuf-compiler automake autoconf libtool nasm

To get a recent cmake, download from https://cmake.org/download/, for example:

wget https://github.com/Kitware/CMake/releases/download/v3.23.1/cmake-3.23.1-linux-x86_64.tar.gz

Build Environments

• singularity 3.5.3
• conda 22.9.0

Larch can be built utilizing a Singularity container or a Conda environment.

To build Singularity image, use the definition provided:

singularity build larch-singularity.sif larch-singularity.def
singularity shell larch-singularity.sif --net

To setup a conda environment capable of building Larch, use:

conda create -n larch
conda activate larch
conda install --channel "conda-forge" --update-deps --override-channels cmake make cxx-compiler openmpi openmpi-mpicc openmpi-mpicxx boost-cpp automake autoconf libtool yasm ucx zlib

To setup a conda environment capable of building Larch including development tools, create larch-dev using the environment file provided:

conda env create -f environment.yml

Building

There are 4 executables that are built automatically as part of the larch package and provide various methods for exploring tree space and manipulating DAGs/trees:

• larch-test is the suite of tests used to validate the various routines.
• larch-usher takes an input tree/DAG and explores tree space through SPR moves.
• merge utility is used to manipulate(e.g. combine, prune)DAGs/trees.
• dag2dot utility writes a provided protobuf file in dot format for easy viewing.

Note: If you run against memory limitations during the cmake step, you can regulate number of parallel threads with export CMAKE_NUM_THREADS="8" (reduce number as necessary).

To build all from larch/ directory, run:

git submodule update --init --recursive
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Debug ..
make -j16

Cmake build options:

• add -DCMAKE_CXX_CLANG_TIDY="clang-tidy" to enable clang-tidy.
• add -DUSE_ASAN=yes to enable asan and ubsan.

Running

larch-test

From the larch/build/ directory:

ln -s ../data
./larch-test

Passing nocatch to the tests executable will allow exceptions to escape, which is useful for debugging. A gdb session can be started with gdb --args build/larch-test nocatch.

larch-test options:

• nocatch allows test exceptions to escape, which is useful for debugging. A gdb session can be started with gdb --args build/larch-test nocatch.
• --list produces a list of all available tests, along with an ID number.
• --range runs tests by ID with a string of comma-separated range or single ID arguments [e.g. 1-5,7,9,12-13].
• -tag excludes tests with a given tag.
• +tag includes tests with a given tag.
• For example, the -tag "slow" removes tests which require an long runtime to complete.

larch-usher

From the larch/build/ directory:

./larch-usher -i ../data/testcase/tree_1.pb.gz -o output_dag.pb -c 10

This command runs 10 iterations of larch-usher on the provided tree, and writes the final result to the file output_dag.pb

larch-usher options:

• -i,--input [REQUIRED] The name of the input tree/DAG (accepted file formats are: MADAG protobuf, MAT protobuf, JSON).
• -o,--output [REQUIRED] The file path to write the resulting DAG to.
• -c,--count [Default: 1] Number of larch-usher iterations to run.
• -r,--MAT-refseq-file [REQUIRED if provided input file is a MAT protobuf] Reference sequence file.
• -v,--VCF-input-file VCF file containing ambiguous sequence data.
• -l,--logpath [Default: optimization_log] Filepath to write log to.
• -s,--switch-subtrees [Default: never] Switch to optimizing subtrees after the specified number of iterations.
• --min-subtree-clade-size [Default: 100] The minimum number of leaves in a subtree sampled for optimization (ignored without option -s).
• --max-subtree-clade-size [Default: 1000] The maximum number of leaves in a subtree sampled for optimization (ignored without option -s).
• --move-coeff-nodes [Default: 1] New node coefficient for scoring moves. Set to 0 to apply only parsimony-optimal SPR moves.
• --move-coeff-pscore [Default: 1] Parsimony score coefficient for scoring moves. Set to 0 to apply only topologically novel SPR moves.
• --sample-method [Default: parsimony] Select method for sampling optimization tree from the DAG. Options are: (parsimony, random, rf-minsum, rf-maxsum).
• --sample-uniformly [Default: use natural distribution] Use a uniform distribution to sample trees for optimization.
• For example, if the sampling method is parsimony and --sample-uniformly is provided, then a uniform distribution on parsimony-optimal trees is sampled from.
• --callback-option [Default: best-moves] Specify which SPR moves are chosen and applied. Options are: (all-moves, best-moves-fixed-tree, best-moves-treebased, best-moves).
• --trim [Default: do not trim] Trim optimized dag to contain only parsimony-optimal trees before writing to protobuf.
• --keep-fragment-uncollapsed [Default: collapse] Do not collapse empty (non-mutation-bearing) edges in the optimization tree.
• --quiet [Default: write intermediate files] Do not write intermediate protobuf file at each iteration.

merge

From the larch/build/ directory:

./merge -i ../data/testcase/tree1.pb.gz -i ../data/testcase/tree2.pb.gz -d -o merged_trees.pb

This executable takes a list of protobuf files and merges the resulting DAGs together into one.

merge options:

• -i,--input Input protobuf files.
• -o,--output [Default: merged.pb] Save the output to filename.
• -r,--refseq [REQUIRED if input protobufs are MAT protobuf format] Read reference sequence from file.
• -d,--dag Input files are MADAG protobuf format\n";
• -t,--trim Trim output (default trimming method is trim to best parsimony).
• --rf Trim output to minimize RF distance to the provided protobuf(Ignored if -t flag is not provided).
• -s,--sample Write a sampled single tree from DAG to file, rather than the whole DAG.

dag2dot

From the larch/build/ directory:

./dag2dot -d ../data/testcase/full_dag.pb

This command writes the provided DAG in dot format to stdout.

dag2dot options:

• -t,--tree-pb Input MAT protobuf filename.
• -d,--dag-pb Input DAG protobuf filename.
• -j,--dag-json Input DAG json filename.

Third-party

• Lohmann, N. (2022). JSON for Modern C++ (Version 3.10.5) [Computer software]. https://github.com/nlohmann
• Eric Niebler. Range library for C++14/17/20. https://github.com/ericniebler/range-v3