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RAxML is a fast program for the inference of phylogenies with maximum likelihood method. RAxML offers several different evolutionary models for both DNA and amino acid sequences.


Free to use and open source under GNU GPLv3.


Version on CSC's Servers

  • Puhti: 8.2.12


To see installed RAxML versions use command:

module spider raxml
To see the requirements for a specific version, use:
module spider raxml/version
module spider raxml/8.2.9
Then load the required modules. For example for version 8.2.12 :
module load raxml/8.2.12

Which Version to use?

RAxML comes in a serial version and three different parallel version.

The serial version (raxmlHPC) is intended for small to medium data sets and for initial experiments to determine appropriate search parameters.

The PThreads version (raxmlHPC-PTHREADS) will work well for very long alignments. Make sure to specify the number of threads with the ­-T option. This should match the number of cores you request in the batch job script.

To choose the number of threads to use, please see section "How many Threads shall I use?" in the RAxML manual. Using too many threads can cause the program to run slower.

The MPI version (raxmlHPC-MPI) is for executing really large production runs (i.e. 100 or 1,000 bootstraps). You can also perform multiple inferences on larger data sets in parallel to find a best-known ML tree for your data set. Finally, the rapid BS algorithm and the associated ML search have also been parallelized with MPI.

The current MPI version only works properly if you specify the number of runs in the command line, since it has been designed to do multiple inferences or rapid/standard BS (bootstrap) searches in parallel. For all remaining options, the usage of this type of coarse-grained parallelism does not make much sense. Please use the -N option instead of the -# option as the latter can be mistaken for a start of a comment by the batch job system.

For versions 8.2.12 and newer there is also a hybrid MPI/threaded version (raxmlHPC-HYBRID)

For versions 8.2.12 and newer there are also AVX optimized binaries available (raxmlHPC-AVX, raxmlHPC-PTHREADS-AVX, raxmlHPC-MPI-AVX, raxmlHPC-HYBRID-AVX) These can run faster that non-optimized versions, but can cause problems on some datasets. Try the non-optimized versions in case of problems.

For details, please refer to chapter "When to use which Version?" in the RAxML manual.

Example batch job script for the PThreads version for Puhti

#SBATCH --account=project_1234567
#SBATCH --job-name=raxml_threads
#SBATCH --ntasks=1
#SBATCH --cpus-per-task=4
#SBATCH --mem=8G
#SBATCH --time=10:00:00
#SBATCH --partition=small

module load raxml/8.2.12
raxmlHPC-PTHREADS -T $SLURM_CPUS_PER_TASK ­-s alg -­m GTRGAMMA ­-p 12345 ­-n test1
Example batch job script for the MPI version for Puhti
#SBATCH --account=project_1234567
#SBATCH --job-name=raxml_mpi
#SBATCH --ntasks=100
#SBATCH --cpus-per-task=1
#SBATCH --mem-per-cpu=8G
#SBATCH --time=10:00:00
#SBATCH --partition=large

module load raxml/8.2.12
srun raxmlHPC-MPI -N 100 -s cox1.phy -m GTRGAMMAI -p 12345 -n test2


Last update: October 10, 2022