All posts by rbou019

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What is new in BEAST v2.3.0 and its packages — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

May 26, 2015 rbou019 Leave a comment

26 May 2015 by Remco Bouckaert

The main improvement is in BEAUti fixes. There are a few bugs, especially with cloning and linking/unlinkig partitions that are fixed. The templates for tree priors have been reorganised, since they some times interferred.

The File-menu in BEAUti is reorganised so it is easier to access files from packages. On the Mac, packages are installed in a rather hard to find folder. With the new menu, it is easy to select a working directory, then import an alignment or open an example file from the package.

The File menu has entries for creating new partitions directly, which saves one click every time an alignment is imported.

The build scripts have been updated so that each applications automatically loads beast.jar instead of having the whole file duplicated in each application, giving smaller footprint for Mac and Windows. This also makes it easier to update using the latest development build; just replace the beast.jar file with the one from here and you are running the development version.

There are a few bug-fixes, in particual, issues with synchronisation affecting ThreadedTreeLikelihood from the BEASTLabs package, a fix in EigenDecomposition affecting asymmetric rate matrices (which caused problems with ancestral reconstruction from the BEAST-CLASSIC package).
Furthre, the code is updated such that dependency on taxon order is reduced, making multiple partition handling more robust

The LogCombiner command line interface is improved so it can take multipe log files as argument, so you can use wildcards to specify multiple files, like so:

logcombiner -log beast.*.log

This version can keep running v2.2 and its packages alongside v2.3, so no need to delete old packages any more.

DensiTree is updated to v2.2.2.

Package added since the last udpate on this blog

There are now 20 packages, many of them added since the last update.

MGSM: multi-gamma site model

Unlike the standard gamma rate heterogeneity model, which uses a single shape parameter, the multi-gamma site model allows the shape parameter to vary over branches. This leads often to better model fit and can result in significantly different divergence time estimates. Preprint on bioRxiv.

Comes with BEAUti support.

Spherial geography

Phyleographical model that assumes heterogeneious diffusion on a sphere, which for large areas can give significantly different results than continuous geography by diffusion on a plane. For a tutorial see here. Preprint on bioRxiv.

Comes with BEAUti support.

bModelTest

A package for nucleotide models that uses reversible jump between a number of substitution models, with and without gamma rate heterogeneity and with and without proportion invariant sites. So, these parts of the model will be estimated during the MCMC run and do not need to be specified beforehand any more. Preprint on bioRxiv.

Comes with BEAUti support.

Morphological-models

Implements the LewisMK model for morphological data, see morphological models. Deals with ambiguities and nexus files for morpholocial data.

Comes with BEAUti support.

Sampled ancestors

Described previously.

The coalescent SIR model

Described previously.

Metroplolis coupled MCMC

Aka MCMCMC or MC3. More here.

Species delimitation with DISSECT and STACEY

Methods for species delimitation based on the multi species coalescent, so this is useful for data that could be analysed using *BEAST. More on this soon.

Bayesian structured coalescent approximation with BASTA

Approximation of the structured coalescent which allows a large number of demes than the pure structured coalescent as for example implemented in the MultiTypeTree package.

Index of 2014 posts — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

May 19, 2015 rbou019 Leave a comment

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Sampled Ancestor Trees in BEAST — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

September 2, 2014 rbou019 Leave a comment

1 September 2014 by Remco Bouckaert

Sampled ancestor trees are trees where the nodes that are sampled need not necessarily be leaf nodes, but can be internal nodes of degree two — that is, they only have one parent (as per usual) and one child. This is useful in the case where there are fossils that represent direct ancestors ofa number of extant species. Another situation is where there is epidemiological data and a patient is sampled multiple times, or an individual was sampled and caused infections which were sampled later. Then earlier samples will be ancestors of later samples. To use sampled ancestors trees in BEAST, you need the sampled ancestor package (easiest to install in BEAUti using the File/Manage Packages menu).

Why use sampled ancestor trees instead of binary trees?

In a transmission tree — trees representing an epidemic — some samples will most likely be direct ancestors of later samples. To ensure correct estimation of parameters, like birth rate or substitution rate, models with sampled ancestors should be used for data where direct ancestors are likely to be present. Not accounting for sampled ancestors leads to biases in parameter estimates. For example, the birth rate lambda will be overestimated if you run with binary trees since there are more birth events in a binary tree than in a sampled ancestor tree. Furthermore, if you want to know who exactly infected who, this is not quite as clear in a binary tree as in a sampled ancestor tree.

Likewise, when you model fossil as part of the speciation process (that is, fossils are samples from the process) then considering binary trees in stead of sampled ancestor trees will introduce biases in estimates of divergence times. The tree prior models the fossilisation process, and parameters in the prior will have a bias in their estimate if binary trees are used.

Tree priors for sampled ancestor trees

The SABDSamplingThroughTimeModel is the default sampled ancestor birth-death-sampling tree prior in the sampled ancestors package. It has the following parameters:

lamba: birth rate
mu: removal rate
psi: sampling rate
r: probability an individual is removed after sampling.
rho: probability of sampling extant species/contemporary individuals.

For the fossilisation process, r=0 because any sample will never be removed, so any of its descendants can be sampled. For r=1, there never is a sampled ancestor. In epidemics r=1 indicates the individuals is removed from the edidemic by sampling. For the transmission process in an epidemic, r is close to 1, depending on type of infection — e.g. it was found to be 0.8 for HIV.

rho is used for contemporary sampling only. It represents the proportion of samples taken out of complete population. For fossilisation, typically rho is close to 1, that is, almost all species relevant to the analysis (belonging to the clade) will be sampled. For epidemics, samples are not contemporary but serially sampled, so rho is not specified.

There is parameter unidentifiability (see this paper) when rho=0.

The birth death sampling model can be used in combination with the skyline model (implemented in the SABDSkylineModel class) where the time spanned by the tree is divided into a number of intervals. Each of these intervals can have its own lambda, mu, psi, r, rho, but they can be shared among intervals as well. For example, you can have a constant mu and psi throughout time, but a different lambda for each interval.

The number of intervals for the skyline model depends on number of times that rates can be expected to be shifted. For instance, if no samples were taken before 1980, but samples are available after 1980, there is a rate shift in sampling rate (psi), so t=1980 is a boundary, and you can specify only psi changed, but that lambda, mu, r (and rho=0) remain the same through the two intervals.

Typically, no sequence data is available for fossils. Without sequence data on fossils, there is no information to infer the tree. In this case, in order to be able to infer the tree, you need at least one parameter, e.g. a strong prior on rho, and lambda, mu and psi can be estimated (r=0). Without fixing rho, all fossils will probably become sampled ancestors, and time estimates will become biased and be estimated too low.

Setting up an analysis

Assuming you set up an analysis in BEAUti say with a Yule model, first of all the tree needs to be replaced by a sampled ancestor tree, the tree operators need to be replaced by those for sampled ancestor trees, so the tree can jump between nodes being ancestors and those being leafs. Further, the Yule model needs to be replaced by the appropriate tree prior, either SABDSamplingThroughTimeModel or SABDSkylineModel.

See the examples in the example directory of the sampled ancestor package for more details.

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Load Balancing — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

August 25, 2014 rbou019 Leave a comment

18 August 2014 by Remco Bouckaert

If you have a good graphics cards, you can use it with BEAGLE to increase the speed of BEAST runs. If you have multiple graphics cards, when starting BEAST from the command line, the -beagle_order flag can be used to tell which thread goes on which GPU. Start BEAST with the -beagle_info flag to find out what kind of hardware you have and which numbers they are.

For example, I get on my aging univesity computer, the following output:

                  BEAST v2.2.0 Prerelease, 2002-2014
       Bayesian Evolutionary Analysis Sampling Trees
                 Designed and developed by
Remco Bouckaert, Alexei J. Drummond, Andrew Rambaut and Marc A. Suchard
                              
               Department of Computer Science
                   University of Auckland
                  remco@cs.auckland.ac.nz
                  alexei@cs.auckland.ac.nz
                              
             Institute of Evolutionary Biology
                  University of Edinburgh
                     a.rambaut@ed.ac.uk
                              
              David Geffen School of Medicine
           University of California, Los Angeles
                     msuchard@ucla.edu
                              
                Downloads, Help & Resources:
              	http://beast2.cs.auckland.ac.nz
                              
Source code distributed under the GNU Lesser General Public License:
              	http://code.google.com/p/beast2
                              
                     BEAST developers:
	Alex Alekseyenko, Trevor Bedford, Erik Bloomquist, Joseph Heled, 
	Sebastian Hoehna, Denise Kuehnert, Philippe Lemey, Wai Lok Sibon Li, 
	Gerton Lunter, Sidney Markowitz, Vladimir Minin, Michael Defoin Platel, 
          	Oliver Pybus, Chieh-Hsi Wu, Walter Xie
                              
                         Thanks to:
    	Roald Forsberg, Beth Shapiro and Korbinian Strimmer

BEAGLE resources available:
0 : CPU
    Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALING_DYNAMIC SCALERS_RAW SCALERS_LOG VECTOR_SSE VECTOR_NONE THREADING_NONE PROCESSOR_CPU


1 : GeForce GTX 295
    Global memory (MB): 896
    Clock speed (Ghz): 1.24
    Number of cores: 240
    Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALING_DYNAMIC SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_CUDA


2 : GeForce GTX 295
    Global memory (MB): 895
    Clock speed (Ghz): 1.24
    Number of cores: 240
    Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALING_DYNAMIC SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_CUDA


3 : GeForce GTX 295
    Global memory (MB): 896
    Clock speed (Ghz): 1.24
    Number of cores: 240
    Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALING_DYNAMIC SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_CUDA


4 : GeForce GTX 295
    Global memory (MB): 896
    Clock speed (Ghz): 1.24
    Number of cores: 240
    Flags: PRECISION_SINGLE PRECISION_DOUBLE COMPUTATION_SYNCH EIGEN_REAL EIGEN_COMPLEX SCALING_MANUAL SCALING_AUTO SCALING_ALWAYS SCALING_DYNAMIC SCALERS_RAW SCALERS_LOG VECTOR_NONE THREADING_NONE PROCESSOR_GPU FRAMEWORK_CUDA

It shows there are 4 GPUs numbered 1 to 4 as well as a CPU numbered 0. It also reports some statistics like the number of cores and memory on each GPU. I understand that on OSX due to a bug in the OpenCL library the reported statistics are somewhat exaggerated (e.g. it reports 280 cores on my Macbook air while the HD Graphics 5000 only has 40).

If I have an analysis with two partitions, or one partition, but using the ThreadedTreeLikelihood instead of the TreeLikelihood, and I would start a job with

beast -beagle_order 2,4 -threads 2 beast.xml

it will use two threads, and the first will use GPU number 2 and the second will use GPU number 4. So, you can divide your data among these cards such that all of your GPUs are utilised.

But what if your dataset is too large to fit on one or more of your GPUs? Then, using the -beagle_order flag can be used with some of the partitions using GPUs and others using CPUs. Say, you have a single GPU numbered 1, and a CPU numbered 0, then using

beast -beagle_order 0,0,0,1 -threads 4 beast.xml

will place the first three threads on the CPU and the last on the GPU. Typically, the CPU and GPU do not run at the same speed and I’ll assume the GPU is much faster. What you will see when running the above is then that the three CPU threads are running behind the GPU. So, the GPU thread will be waiting on the CPU threads to finish, and this shows up in CPU load being well below 400% On Mac or Linux I use ‘top’ to see how much CPU load there is. If you could put less data on the CPUs and more on the GPU, you could utilise your computer more efficient.

Now you can — this requires BEAST v2.2.0-pre release, and BEASTlabs for v2.2.0. The ThreadedTreeLikelihood has a proportions attribute where you can specify how much of the data should go into a thread. By default, the ThreadedTreeLikelihood splits up the data in equal parts, which is fine if you only use CPU or only GPU. But when you mix, the proportions specifies proportions of patterns used per thread as space delimited string. This is useful when using a mixture of BEAGLE devices that run at different speeds, e.g GPU and CPU. The string is duplicated if there are more threads than proportions specified. For example, ‘1 2′ as well as ’33 66’ with 2 threads specifies that the first thread gets one third of the patterns and the second two thirds. With 3 threads, it is interpreted as ‘1 2 1’ = 25%, 50%, 25% and with 7 threads it is ‘1 2 1 2 1 2 1’ = 10% 20% 10% 20% 10% 20% 10%. If not specified, all threads get the same proportion of patterns.

By keeping an eye on CPU utilisation, you can see how changing proportions have an impact on CPU load.

Note that mixing the -beagle_GPU and -beagle_SSE flag causes all threads to use CPUs, so the CPU necessarily cannot use the SSE instructions, which means in most practical cases some speed is lost.

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The coalescent SIR model in BEAST — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

August 18, 2014 rbou019 Leave a comment

18 August 2014 by Remco Bouckaert

Today, we have a look at Volz’s coalescent SIR model, which is an epidemic model that assumes there are three states: susceptible (S), infected (I) and removed (R). To use it, you need to install the phylodynamics package through the package manager. You might want to use coalescent SIR instead of birth-death SIR (BDSIR) — also in the phylodynamics package — since the coalescent model can give smaller confidence intervals.

The coalescent SIR model

The model allows you to estimate the basic reproduction number, R0, which is the average number of people that become infected by each one that is infected. R0 is important, since it mostly determines the size of an epidemic. Other parameters in the model are the transmission rate beta, which is the rate at which new infections arise and the removal rate, gamma. Gamma is often called ‘recovered’ instead of ‘removed’, but since there are other ways to get into state R (by patients dying, or by becoming a sample in our data) the term ‘removed’ is more accurate. Beta and Gamma can be interpreted as birth and death rates, moving from susceptible state S into the infected state I and from the infected state I into removed state R. Further, there is the initial size of susceptible population S0 and time of origin of the infection z0. Obviously, z0 must always be before the root of the tree. At z0, it is assumed there is just a single infected person and throughout the epidemic the population size is constant at size S0+1. For more information, see this paper.

In summary, we have

R0, basic reproduction number
beta, transmission rate
gamma, removal rate
S0, initial number of susceptibles
z0, time of origin.

Some of these parameters are functionally related through R0=beta*S0/gamma. This means, you can estimate either R0 or beta, and all the others, and then calculate R0 or beta through the formula. There are two implementations: a deterministic and a stochastic one. The stochastic model simulates trajectories of S, I, and R by a jump process while the deterministic model solve a set of ODEs for S, I and R. The stochastic model is much slower — it can be 3 times slower than deterministic — however, stochastic processes more closely represent reality and incorporating them may significantly affect the inference in some cases. For large R0 >1.5 and large S0, deterministic coalescent SIR is both faster and accurate, but for small R0 <1.5 deterministic tends to have the smallest positive bias on R0 and more often have R0 in the 95%HDP (in a simulation study comparing stochastic SIR, deterministic SIR and BDSIR).

Using the model in XML

To use the model, you incorporate serially sampled data by specifying a date trait for sequences.

First, add state nodes to the state element — values need to be adapted for your analysis. Good values help in getting convergence — bad values may result in the chain getting stuck. Makes sure the origin is old enough that it comes before the root of the tree. An error will be thrown when it does not. Here, we estimate R0, and derive beta, so there is no state node for beta.

To set S0 take an estimate of the population size of the area susceptible to the epidemy.
Basic reproductive number R0 must be larger than 1 (otherwise there will be no epidemic) and people disagree on what a high value of R0 is — some say 2.5, but others think 10 is possible.
Gamma removal rate: a high gamma (like in the current ebola outbreak) means fewer overall infected people, high chance of death or quarantine, or recovery with immunity.
z0 must be above root of initial tree, but setting it too high means burn-in may take a long time, so lower values are recommended.

Add priors to element with id=”prior” for S0, R0, gamma and origin — these are just default priors, but if you have more information you should adapt these. For origin z0 – typically not much info available, so uniform with a limited upper bound will do. Note uniform[0,100] means there is 99% that origin is over 1 — check your units of time whether this is relevant for your analysis.

The CSIR model is effectively a tree prior, so we add it to the element with id=”prior”. This adds a deterministic CSIR prior to the analysis (for stochastic CSIR, see below):

Now, we add operators — in this case beta is solved through R0=beta*S0/gamma, so only operators for S0, gamma, R0 and origin are added:

If you have an up-down operator for clock and tree, add origin

If you want to know what the parameters are, add loggers to the trace-log:

Run the analysis in BEAST. There are R scripts (ask Alex Popinga) to get nice plots from these.

The stochastic coalescent SIR model

To add the stochastic CSIR model instead of the deterministic one, the only difference is that the tree prior should be replaced by this:

It is best to set minTraj=1 and minTrajSuccess=1 initially. If there are mixing problems, increase minTraj and minTrajSuccess (minTrajSucces<=minTraj). Increasing numSamplesFromTrajectory will slow things down considerably. 101 tends to be good enough, but in bad mixing increasing it may help, but will slow things down more than increasing minTraj, so try that first.

Coming up

There should be a BEAUti template soon so you can select Coalescent SIR as tree prior and do not worry about the details of the XML.

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BEAST on OSX trouble shooting — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

August 11, 2014 rbou019 Leave a comment

11 August 2014 by Remco Bouckaert

Just this week I got a new Mac laptop, and could experience first hand what it is to install BEAST on a virgin machine. There are number of reasons why BEAST will not start on Apple OSX, and we have a look at the most common causes and how to solve them.

DMG is ‘damaged’

First of all, after downloading BEAST and OSX may respond to opening the dmg file by showing a dialog with the message that the file is damaged and offers a choice of deleting or canceling the action.

By default, security settings on Mavericks is that only apps downloaded from Mac App Store and from identified developers are opened, and anything else is treated with the message shown above. To fix this, open the security and privacy settings — click the apple icon in the top left corner, then click System Preferences, and select Security & Privacy. A window similar to this will be shown:

You need to change that to allow apps from anywhere. Once you click that, a window pops up asking whether you want to make your computer less secure. No worries — after starting BEAST once, you can set it back to a more secure setting.

Cannot be opened

Another message that can pop up is that BEAST or BEAUti cannot be opened — something similar to this

(Had to doctor this screenshot a bit to show beast instead of the app I started). Again, change the security settings (temporarily) to allow applications from anywhere, as outlined above.

Need to install Java 6?

Now the dmg file should open and you can drag BEAST to the Applications folder. Double clicking BEAUti or BEAST may result in a message asking you to install Java 6. This may seem strange if you already have Java 7 or higher installed.

It does not change your default Java installation if you click ‘install’ — Java 6 will be installed next to Java 7 or 8, but will not become the default for command line usage.
(you may want to create a symbolic link to trick OSX in thinking Java 6 is already installed if you already have Java 7 — details here).

BEAST does not start from the command line

When you run BEAST or BEAUti from the command line, you can be confronted by a somewhat mysterious message like this:

Exception in thread "main" java.lang.UnsupportedClassVersionError: beast/app/beauti/Beauti : Unsupported major.minor version 52.0

BEAST v2.1.x requires Java 6 and v2.2.x requires Java 8. It is possible that you do not have the correct version of Java installed. To test which version you have, in a terminal use “java -version”, which should display something like this:

~> java -version
java version "1.8.0_11"
Java(TM) SE Runtime Environment (build 1.8.0_11-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.11-b03, mixed mode)

(~> is the command prompt, and should not be typed. Anything with out ~> is output to screen.) If you do not have the correct Java version installed, you can do so from java.com or for Java 8 oracle. It is possible that you have more than one version of Java installed, and that the default version happens to be an older version. To change the default version is a bit fiddly, but can be done from a terminal by changing a symbolic link in /System/Library/Frameworks/JavaVM.framework/Versions/ like so:

~> cd /System/Library/Frameworks/JavaVM.framework/Versions/
~> ls
CurrentJDK

If it shows something else, e.g., Current replace CurrentJDK with the name of that link.

~> rm CurrentJDK
~> ls /Library/Java/JavaVirtualMachines/
jdk1.7.0_21.jdk     jdk1.8.0_11.jdk

Now, just select one of the Java versions, say jdk1.8.0_11.jdk and add the link

~> ln -s /Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/ CurrentJDK

Don’t forget to replace CurrentJDK with Current if that is what you had before.

BEAGLE and CUDA

BEAGLE is a library for performing Felsenstein’s peeling algorithm much more efficiently than can be done in Java. To install it for Mac is straightforward, but sometimes it does not work. One of the reasons is that the BEAGLE installer makes it easy to let you install CUDA as well. The CUDA library is useful only when you have an NVIDA graphics card. Most Macs that I’ve seen do not have an NVIDIA card, and on these machines you can see errors similar to this:

CUDA error: "Driver not initialized" from file , line 169.

What you need to do is uninstall the CUDA driver — reinstalling the BEAGLE library may be helpful as well.

Uninstalling CUDA drivers is a bit of a mission, since files go in a number of places, and there is no uninstaller. What should work is to delete all of the following files

/Library/Frameworks/CUDA.framework
/Library/LaunchAgents/com.nvidia.CUDASoftwareUpdate.plist
/Library/PreferencePanes/CUDA Preferences.prefPane
/System/Library/Extensions/CUDA
/System/Library/StartupItems/CUDA
/usr/local/cuda/lib/libcuda.dylib

then reboot, and CUDA should be uninstalled.

Accessing packages

BEAST packages typically come with usefule examples and documentation. On OSX, packages are stored in ~/Library/Application Support/BEAST/2.1/ and each package has its own directory with the name of the package. The OSX Finder does not show the ~/Library folder by default. To open the folder, click the Go-item in the menu bar, then hit the alt-key. Now ‘Library’ appears under the Go-menu. Select the Library-item and a new folder opens from where you can browse to the BEAST package.

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BEAST Apps for the AppStore — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

August 4, 2014 rbou019 Leave a comment

4 August 2014 by Remco Bouckaert

Say, you have some post-processing classes written for your package and you want to make it available to users. Since the class is in your package, say mypackage.addon.jar and most likely you need classes from BEAST-core or other packages, it is a nuisance to set the class path from the command line. You’ll and up having to do something like

java -cp /path/to/beast/lib/beast.jar:~/.beast/2.1/MyPackage/lib/mypackage.addon.jar beast.app.tools.MyTool arg1 arg2 arg3

This is especially cumbersome to explain to users since these paths depend on where BEAST is installed and where packages are installed. These paths are operating system dependent. One solution to this is to use the BEAST AppStore. This is an application that comes with BEAST. It picks up information from the version.xml file. You specify an addonapp element with a description, class, default arguments and an icon. For example, the model-selection package contains an application to run a path sampling analysis, which is encoded like so:

When you start the AppStore, it will look like this:

If you launch it from the AppStore, you probably want to launch it as a GUI, since Windows and Mac users won’t be able to see any terminal input otherwise. You can write your own GUI in Swing or JavaFX if you like, but there are a few helper classes that make it very easy to write GUI applications with BEAST. The recipe is as follows:

Create a class for your App that derives from beast.core.Runnable.
Specify Inputs for each of the arguments for your application.
Implement the run() method to pick up values from inputs and run your app.
Create a class to launch the App.
Update the version.xml file

Path sample analyser application

Step 1: create class for App

The path sample analyser lives in the class beast.inference.PathSampleAnalyser and derives from beast.core.Runnable.

@Description("Reads logs produces through PathSampler and estimates marginal likelihood")
public class PathSampleAnalyser extends beast.core.Runnable {
}

Step 2: specify inputs

For the path sample analyser, we need a root directory, alpha, number of steps and burnin as a percentage. So, we add the following Inputs to the class.

public Input rootDirInput = new Input("rootdir", "root directory for storing particle states and log files (default /tmp)", "/tmp");
public Input alphaInput = new Input("alpha", "alpha parameter of Beta(alpha,1) distribution used to space out steps, default 0.3" +
		"If alpha <= 0, uniform intervals are used.", 0.3);
public Input stepsInput = new Input("nrOfSteps", "the number of steps to use, default 8", 8);
public Input burnInPercentageInput = new Input("burnInPercentage", "burn-In Percentage used for analysing log files", 50);

Step 3: implement `run()` method

The actual post-processing happens in the method estimateMarginalLikelihood. The run method just gather info from the inputs and passes it to that worker method.

@Override
public void run() throws Exception {
    // do the work
    double marginalL = estimateMarginalLikelihood(
			stepsInput.get(), 
			alphaInput.get(), 
			rootDirInput.get(), 
			burnInPercentageInput.get());

	// report the result       
	System.out.println("marginal L estimate = " + marginalL);
}

Step 4: Create launcher class

Create a class to launch the App. This is the class that you register in the version.xml file. The following bit of code can be used as a template for your own app — just replace the class for the analyser variable and update name and title. It uses two utility classes beast.app.util.Application and beast.app.util.ConsoleApp (currently in the model-selection package, but it should probably move somewhere else). You can also suppress inputs that you do not want to expose to the user.

package beast.app.tools;

import beast.app.beauti.BeautiConfig;
import beast.app.beauti.BeautiDoc;
import beast.app.draw.BEASTObjectDialog;
import beast.app.draw.BEASTObjectPanel;
import beast.app.util.Application;
import beast.app.util.ConsoleApp;

//command line interface to PathSampleAnalyser
public class PathSampleAnalyser {
		
	public static void main(final String[] args) throws Exception {
		Application main = null;
		try {
			// create the runnable class with application that we want to launch
			beast.inference.PathSampleAnalyser analyser = new beast.inference.PathSampleAnalyser();
			
			// need to set the ID of the BEAST-object
			analyser.setID("PathSampleAnalyser");
			
			// then initialise
			analyser.initAndValidate();
			
			// create BeautiDoc and beauti configuration
			BeautiDoc doc = new BeautiDoc();
			doc.beautiConfig = new BeautiConfig();
			doc.beautiConfig.initAndValidate();

			// This is how you suppress an input that we don't want to expose to the user
			// doc.beautiConfig.suppressPlugins.add(analyser.getClass().getName() + ".input-name");

		
			// create panel with entries for the application
			BEASTObjectPanel panel = new BEASTObjectPanel(analyser, analyser.getClass(), doc);
			
			// wrap panel in a dialog
			BEASTObjectDialog dialog = new BEASTObjectDialog(panel, null);
			if (dialog.showDialog()) {
				dialog.accept(analyser, doc);
				analyser.initAndValidate();

				// create a console to show standard error and standard output
				analyser.consoleApp = new ConsoleApp("PathSampleAnalyser", // name 
						"Path Sample Analyser: " + analyser.rootDirInput.get() // console title
						);

				analyser.run();
			}
		} catch (Exception e) {
			System.out.println(e.getMessage());
			if (main != null) {
				System.out.println(main.getUsage());
			}
		}
	}

}

Update the `version.xml` file

Add an addonapp element to the version.xml file, so the AppStore can pick it up.

When launching the PathSampleAnalyser from the AppStore, it looks like this:

Blog

All about starting trees — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

July 28, 2014 rbou019 Leave a comment

28 July 2014 by Remco Bouckaert

Before starting an MCMC run, BEAST uses State Node initialisers to set up the starting trees (and other parameters). Often a good starting tree is already available from another analysis (e.g. a maximum likelihood tree). Though it is against the spirit of MCMC, which guarantees any random starting state will lead to convergence, a good starting tree can help with large analysis to speed up convergence quite a bit. Of course another reason to specify a starting tree is if you want to do an analysis using just a single known tree topology.

We start with standard analysis, but see below for *BEAST analyses.

Standard analysis

For a standard analysis, there are three ways to specify a starting tree

a random tree
a tree in Newick format
a cluster tree, e.g. through UPGMA or neighbour joining

By default, BEAUti uses a RandomTree state-node initialiser to generate a starting tree. If you want to replace it with a Newick tree or cluster tree, first you need to remove (or comment out) the RandomTree element from the XML. For a tree in partition XYZ26, just search for RandomTree and remove the XML fragment with id RandomTree.t:XYZ26. It should look something like this:

1.0

Before removing, make note of the initial attribute (@Tree.t:XYZ26> here) and taxa attribute (@XYZ26 here).

Newick starting tree

After removing the Random tree, in the same place, add a TreeParser using the following fragment

The attributes that you want to specify are

id="NewickTree.t:XYZ26" the ID should be unique, so something like NewickTree.t: plus the name of the tree would be suitable.
initial="@Tree.t:XYZ26" this refers to the tree being initialised. It should be the same as the initial attribute of the RandomTree that was removed.
taxa="@XYZ26" this refers to the alignment and ensures that taxa in the tree are lined with those in the alignment. For BEAST v2.1.x, this must be specified to prevent starting with a mislabelled tree
newick="((your,(tree,goes)),here)" obviously needs to be replaced with your own tree in Newick format.

This is all you need to know to set up a starting tree. There are a few optional attributes you can use to make life a bit easier:

adjustTipHeights is true by default, which means tips of the tree will be set to zero, or if tip dates are specified to these particular tip dates. By setting to adjustTipHeights="false", tips will be initialised by the heights in the Newick tree.
if adjustTipHeights="false" then threshold specifies threshold under which node heights (derived from lengths) are set to zero. This helps when there are numeric issues with adding the lengths.
scale scale used to multiply internal node heights during parsing. Useful for importing starting from external programs, for instance, RaxML tree rooted using Path-o-gen.
IsLabelledNewick="true" Is the Newick tree labelled (alternatively contains node numbers)?
If sLabelledNewick="false" then “offset="1" is the lowest taxa number. The default=1 but 0 is common as well. Taxa numbers are as they are ordered in the alignment referred to with the taxa attribute.

Cluster tree

After removing the Random tree, in the same place, add a ClusterTree with the following fragment

The attributes that you need to specify are id='UPGMATree.t:XYZ26', initial="@Tree.t:XYZ26" and taxa="@XYZ26", which are as for Newick tree (see above).

You can use different clustering algorithms by specifying the clusterType="upgma" attribute.

clusterType	Description
single	single link
complete	complete link
upgma or average	UPGMA=average link
mean	mean link
centroid	centroid
ward	Ward’s method
adjcomplete	adjusted complete link
neighborjoining	neighborjoining
neighborjoining2	neighborjoining2 – corrects tree for tip data, unlike plain neighborjoining

*BEAST analysis

For a *BEAST analysis, the default in BEAUti is to generate a UPGMA tree for the species tree, then generate UPGMA trees for each of the gene trees and fit them inside the species tree. In previous incarnations of BEAST, a random tree was generated for species as well as for gene trees, but gene tree branches ending in leaves were lengthened such that each first coalescence of a gene tree was above the root of the species tree. Though this ensures that the gene trees fit inside the species tree, it leads to long burn-in times.

If you want to use a different starting tree for the species tree, first move (not remove!) the StarBeastStartState element generated by BEAUti to just before the run-element with id="mcmc". BEAUti will have generated some elements inside the start-state (such as the species-tree-prior) that we need elsewhere in the analysis. By moving the init element outside the run element, it will not activate the StarBeastStartState.

The StarBeastStartState looks something like this:

For every gene tree there will be a tree entry in the StarBeastStartState. To replace the species tree with a Newick tree, add the following fragment (at the place where the StarBeastStartState was):

The only thing to set up is the Newick using the newick attribute — all other attributes should be as they are (it is using the species tree, which is identified by the Species partition in every *BEAST analysis generated by BEAUti).

For each of the gene trees, you need to specify a tree as well. You can specify them using a Newick tree as for the Standard analysis (see above). Alternatively, you can use a random tree that is placed ‘above’ the species tree. To do this, you add for the first gene tree (just below the new Species tree start tree):

where you replace the initial='@Tree.t:26' and taxa="@26" attributes to match your tree (instead of 26, as in this example). For every subsequent gene tree, you add (below the first gene start tree):

where you replace the initial='@Tree.t:29' and taxa="@29" attributes to match your tree (instead of 29) and make sure the id is unique.

Blog

SNAPP handling missing data and path sampling made easier — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

July 21, 2014 rbou019 Leave a comment

21 July 2014 by Remco Bouckaert

SNAPP treats each SNP as having its own gene tree, but what happens when there is data missing for some sites for a SNP? SNAPP simply assumes these taxa do not exist in the gene tree. If you have a species containing 3 lineages for which one has missing data, SNAPP assumes there is a gene tree with only 2 lineages for that species. So, what happens when all 3 lineages is missing? Previous versions of SNAPP (v1.1.5 and before) could not handle this situation and just removed these sites from the data. This can be a problem when you do species delimitation using BFD*; when you split a species and data is missing, some sites may be deleted that are not deleted when doing the un-split analysis. As a results, marginal likelihoods are calculated for different data sets, so these are not comparable. In v1.1.6, no sites with missing data are deleted any more, even when this leaves some species having zero lineages. SNAPP assumes the gene tree simply has no taxa in that species any more.

Another change in SNAPP v1.1.6 is that it uses the MCMC class from BEAST instead of SNAPP, which means there is no timeout and sampling from prior options any more, but this makes doing a path sampling analysis a lot easier.

First, make sure you have SNAPP at least v1.1.6 installed and Model Selection v1.0.2. Open the package manager (in BEAUti under the File/Manage packages menu) and select SNAPP, then click the Install button. After a little while a warning pops up that SNAPP is installed, and you might need to restart BEAUti to be able to set up a SNAPP analysis.

Then, select the SNAPP template, to set up a SNAPP analysis.

Click import data, and select a nexus file with your alignment. The taxa will automatically be assigned to a species by guessing based on the lineage names in the nexus files. You can change this of course.

In the Model Parameters panel, make sure you either calculate the values for u and v (see the Rough guide to SNAPP how to do this) or just click the estimate flag next to Mutation Rate U. When there is a sufficient amount of SNP data the estimates for U and V converge quite rapidly most of the time. Note: Leaving the default values for u and v and not estimating these mutation rates is almost surely going to lead to bad fits!

You can save this analysis as XML file, say runA.xml and run it with BEAST.

Now, if you want to calculate the marginal likelihood, you can start the AppStore application that is part of BEAST, and select the Path Sampler icon — either double click or click launch to start the Path sampler.

A window pops up where you can select the XML file you save from BEAUti and specify the parameters for the path sampling analysis.

Once you click OK, the path sampling analysis is set up and run in a separate window, where after a little (or long — depending on the data) while the marginal likelihood will be printed.

Blog

Path sampling with a GUI — this site is deprecated: goto https://www.beast2.org/ for up-to-date information

July 14, 2014 rbou019 Leave a comment

14 July 2014 by Remco Bouckaert

Requires the model-selection package version 1.0.2 or better. See here how to manage packages.

Instead of editing the XML, as explained in the BEAST website, a path sampling, or stepping stone analysis can be set up using a GUI as well. First, launch the appstore — there should be an icon labelled ‘AppStore’ when BEAST is installed, just double click that.

When you filter applications on MODEL-SELECTION using the drop-down box at the top of the AppStore, there should be an icon labelled Path Sampler and another labelled Path Sample Analysis. Launch the Path Sampler by double clicking the icon.

A dialog pops up showing a range of options for setting up the path sampling or stepping stone analysis. As you can see, one of the inputs called Model1 is the XML file containing the BEAST analysis for which you want to estimate the marginal likelihood. Here we selected normalTest-1.xml which is in the examples directory of the MODEL-SELECTION package.

Set the other parameters as appropriate. Note that in this screen-shot we chose 4 steps just to ran it fast, but that does not mean that 4 steps is sufficient. You want to keep increasing the number of steps till the marginal likelihood estimate remains constant. There is no rule of thumb other than this to find the number of steps as far as I know.

If you already ran a path sampling analysis before, you want to overwrite the log files, and click the “Delete old logs” check box.

Once you click OK, the analysis is started (if you left the Do Not Run check-box unchecked) and a window pops up showing progress of the analysis. At the end, the marginal likelihood estimate is printed:

If you selected “Do not run”, all files and directories will be created, but the analysis is not run yet. You can run them by kicking of the run.sh/run.bat scripts (depending on your operating system). Once the analysis is run — or for some steps re-run if something went wrong — you need to start the path-sample analyser to calculate the ML estimate from the individual steps. This is easy — from the AppStore launch the path-sampling analyser:

A window pops up where you can specify the same path sampling parameters as used for the analysis:

When you click OK, a window pops up where after a little while the marginal likelihood estimate is printed:

Package added since the last udpate on this blog

MGSM: multi-gamma site model

Spherial geography

bModelTest

Morphological-models

Sampled ancestors

The coalescent SIR model

Metroplolis coupled MCMC

Species delimitation with DISSECT and STACEY

Bayesian structured coalescent approximation with BASTA

More tutorials

Why use sampled ancestor trees instead of binary trees?

Tree priors for sampled ancestor trees

Setting up an analysis

The coalescent SIR model

Using the model in XML

The stochastic coalescent SIR model

Coming up

DMG is ‘damaged’

Cannot be opened

Need to install Java 6?

BEAST does not start from the command line

BEAGLE and CUDA

Accessing packages

Path sample analyser application

Step 1: create class for App

Step 2: specify inputs

Step 3: implement run() method

Step 4: Create launcher class

Update the version.xml file

Standard analysis

Newick starting tree

Cluster tree

*BEAST analysis

Bayesian evolutionary analysis by sampling trees

Step 3: implement `run()` method

Update the `version.xml` file