Science has driven the development of the NEST simulator for the past 20 years. Originally created to simulate the propagation of synfire chains using single-processor workstations, we have pushed NEST’s capabilities continuously to address new scientific questions and computer architectures. Prominent examples include studies on spike-timing dependent plasticity in large simulations of cortical networks, the verification of mean-field models, models of Alzheimer’s and Parkinson’s disease and tinnitus. Recent developments include a significant reduction in memory requirements, as demonstrated by a record-breaking simulation of 1.86 billion neurons connected by 11.1 trillion synapses on the Japanese K supercomputer, paving the way for brain-scale simulations.
Running on everything from laptops to the world’s largest supercomputers, NEST is configured and controlled by high-level Python scripts, while harnessing the power of C++ under the hood. An extensive testsuite and systematic quality assurance ensure the reliability of NEST.
The development of NEST is driven by the demands of neuroscience and carried out in a collaborative fashion at many institutions around the world, coordinated by the non-profit member-based NEST Initiative. NEST is released under GNU Public License version 2 or later.
How NEST has been improved in HBP
Continuous dynamics
The continuous dynamics code in NEST enables simulations of rate- based model neurons in the event-based simulation scheme of the spiking simulator NEST. The technology was included and released with NEST 2.14.0.
Furthermore, additional rate-based models for the Co-Design Project “Visuo-Motor Integration” (CDP4) have been implemented and scheduled for NEST release 2.16.0.
NESTML is a domain-specific language that supports the specification of neuron models in a precise and concise syntax, based on the syntax of Python. Model equations can either be given as a simple string of mathematical notation or as an algorithm written in the built-in procedural language. The equations are analyzed by NESTML to compute an exact solution if possible, or use an appropriate numeric solver otherwise.
This technology couples the simulation software NEST and UG4 by means of the MUSIC library. NEST can only send spike trains where spiking occurs; UG4 receives those in form of events arriving at synapses (timestamps). The time course of the extracellular potential in a cube (representing a piece of tissue) is simulated based on the arriving spike data.The evolution of the membrane potential in space and time is described by the Xylouris-Wittum model.
Link to this release (2017): https://github.com/UG4
The development of MonetDB was co-funded by the HBP during the Ramp-up Phase. This page is kept for reference but will no longer be updated.
When a database grows into millions of records spread over many tables and business intelligence or science becomes the prevalent application domain, a column-store database management system (DBMS) is called for. Unlike traditional row-stores, such as MySQL and PostgreSQL, a column-store provides a modern and scalable solution without calling for substantial hardware investments.
MonetDB pioneered column-store solutions for high-performance data warehouses for business intelligence and eScience since 1993. It achieves its goal by innovations at all layers of a DBMS, e.g. a storage model based on vertical fragmentation, modern CPU-tuned query execution architecture, automatic and adaptive indices, run-time query optimization, and a modular software architecture. It is based on the SQL 2003 standard with full support of foreign keys, joins, views, triggers, and stored procedures. It is fully ACID compliant and supports a rich spectrum of programming interfaces (JDBC, ODBC, PHP, Python, RoR, C/C++, Perl).
The current version provides the following new features as compared to the version that was part of the HBP-internal Platform Release in M18:
The development of PyCOMPSs was co-funded by the HBP during the Ramp-up Phase. This page is kept for reference but will no longer be updated, apart from release notes.
PyCOMPSs is the Python binding of COMPSs, (COMP Superscalar) a coarse-grained programming model oriented to distributed environments, with a powerful runtime that leverages low-level APIs (e.g. Amazon EC2) and manages data dependencies (objects and files). From a sequential Python code, it is able to run in parallel and distributed.
COMPSs screenshot
Releases
PyCOMPSs is based on COMPSs. COMPSs version 1.3 was released in November 2015, version 1.4 in May 2016 and version 2.0 in November 2016.
New features in COMPSs v1.3
Runtime
Persistent workers: workers can be deployed on computing nodes and persist during all the application lifetime, thus reducing the runtime overhead. The previous implementation of workers based on a per task process is still supported.
Enhanced logging system
Interoperable communication layer: different inter-nodes communication protocol is supported by implementing the Adaptor interface (JavaGAT and NIO implementations already included)
Simplified cloud connectors interface
JClouds connector
Python/PyCOMPSs
Added constraints support
Enhanced methods support
Lists accepted as a tasks’ parameter type
Support for user decorators
Tools
New monitoring tool: with new views, as workload and possibility of visualizing information about previous runs
Enhanced tracing mechanism
Simplified execution scripts
Simplified installation on supercomputers through better scripts
New features in COMPSs v1.4
Runtime
Added support for Docker
Added support for Chameleon Cloud
Object cache for persistent workers
Improved error management
Added connector for submitting tasks to MN supercomputer from external COMPSs applications
Bug-fixes
Python/PyCOMPSs
General bug-fixes
Tools
Enhanced Tracing mechanism:
Reduced overhead using native Java API
Added support for communications instrumentation added
Added support for PAPI hardware counters
Known Limitations
When executing Python applications with constraints in the cloud the initial VMs must be set to 0
New features in COMPSs v2.0 (released November 2016)
Runtime:
Upgrade to Java 8
Support to remote input files (input files already at workers)
Integration with Persistent Objects
Elasticity with Docker and Mesos
Multi-processor support (CPUs, GPUs, FPGAs)
Dynamic constraints with environment variables
Scheduling taking into account the full tasks graph (not only ready tasks)
Support for SLURM clusters
Initial COMPSs/OmpSs integration
Replicated tasks: Tasks executed in all the workers
Explicit Barrier
Python:
Python user events and HW counters tracing
Improved PyCOMPSs serialization. Added support for lambda and generator parameters.
C:
Constraints support
Tools:
Improved current graph visualization on COMPSs Monitor
Improvements:
Simplified Resource and Project files (NO retrocompatibility)
Improved binding workers execution (use pipes instead of Java Process Builders)
Simplifies cluster job scripts and supercomputers configuration
Several bug fixes
Known Limitations:
When executing python applications with constraints in the cloud the initial VMs must be set to 0
New features in PyCOMPSs/COMPSs v2.1 (released June 2017)
New features:
Runtime:
New annotations to simplify tasks that call external binaries
Integration with other programming models (MPI, OmpSs,..)
Support for Singularity containers in Clusters
Extension of the scheduling to support multi-node tasks (MPI apps as tasks)
Support for Grid Engine job scheduler in clusters
Language flag automatically inferred in runcompss script
New schedulers based on tasks’ generation order
Core affinity and over-subscribing thread management in multi-core cluster queue scripts (used with MKL libraries, for example)
Python:
@local annotation to support simpler data synchronizations in master (requires to install guppy)
Support for args and kwargs parameters as task dependencies
Task versioning support in Python (multiple behaviors of the same task)
New Python persistent workers that reduce overhead of Python tasks
Support for task-thread affinity
Tracing extended to support for Python user events and HW counters (with known issues)
C:
Extension of file management API (compss_fopen, compss_ifstream, compss_ofstream, compss_delete_file)
Support for task-thread affinity
Tools:
Visualization of not-running tasks in current graph of the COMPSs Monitor
Improvements
Improved PyCOMPSs serialization
Improvements in cluster job scripts and supercomputers configuration
Several bug fixes
Known Limitations
When executing Python applications with constraints in the cloud the <InitialVMs> property must be set to 0
Tasks that invoke Numpy and MKL may experience issues if tasks use a different number of MKL threads. This is due to the fact that MKL reuses threads in the different calls and it does not change the number of threads from one call to another.
New features in PyCOMPSs/COMPSs v2.3 (released June 2018)
Runtime
Persistent storage API implementation based on Redis (distributed as default implementation with COMPSs)
Support for FPGA constraints and reconfiguration scripts
Support for PBS Job Scheduler and the Archer Supercomputer
Java
New API call to delete objects in order to reduce application memory usage
Python
Support for Python 3
Support for Python virtual environments (venv)
Support for running PyCOMPSs as a Python module
Support for tasks returning multiple elements (returns=#)
Automatic import of dummy PyCOMPSs AP
C
Persistent worker with Memory-to-memory transfers
Support for arrays (no serialization required)
Improvements
Distribution with docker images
Source Code and example applications distribution on Github
Automatic inference of task return
Improved obsolete object cleanup
Improved tracing support for applications using persistent memory
Improved finalization process to reduce zombie processes
Several bug fixes
Known limitations
Tasks that invoke Numpy and MKL may experience issues if a different MKL threads count is used in different tasks. This is due to the fact that MKL reuses threads in the different calls and it does not change the number of threads from one call to another.
New features in PyCOMPSs/COMPSs v2.5 (released June 2019)
Runtime:
New Concurrent direction type for task parameter.
Multi-node tasks support for native (Java, Python) tasks. Previously, multi-node tasks were only posible with @mpi or @decaf tasks.
@Compss decorator for executing compss applications as tasks.
New runtime api to synchronize files without opening them.
Customizable task failure management with the “onFailure” task property.
Enabled master node to execute tasks.
Python:
Partial support of numba in tasks.
Support for collection as task parameter.
Supported task inheritance.
New persistent MPI worker mode (alternative to subprocess).
Support to ARM MAP and DDT tools (with MPI worker mode).
C:
Support for task without parameters and applications without src folder.
Improvements:
New task property “targetDirection” to indicate direction of the target object in object methods. Substitutes the “isModifier” task property.
Warnings for deprecated or incorrect task parameters.
Improvements in Jupyter for Supercomputers.
Upgrade of runcompss_docker script to docker stack interface.
Several bug fixes.
Known Limitations:
Tasks that invoke Numpy and MKL may experience issues if a different MKL threads count is used in different tasks. This is due to the fact that MKL reuses threads in the different calls and it does not change the number of threads from one call to another.
C++ Objects declared as arguments in a coarse-grain tasks must be passed in the task methods as object pointers in order to have a proper dependency management.
Master as worker is not working for executions with persistent worker in C++.
Coherence and concurrent writing in parameters annotated with the “Concurrent” direction must be managed by the underlaying distributed storage system.
Delete file calls for files used as input can produce a significant synchronization of the main code.
PyCOMPSs/COMPSs PIP installation package
This is a new feature available since January 2017.
Installation:
Check the dependencies in the PIP section of the PyCOMPSs installation manual (available at the documentation section of compss.bsc.es). Be sure that the target machine satisfies the mentioned dependencies.
The installation can be done in various alternative ways:
Use PIP to install the official PyCOMPSs version from the pypi live repository:
sudo -E python2.7 -m pip install pycompss -v
Use PIP to install PyCOMPSs from a pycompss.tar.gz
The development of Deflect Client Library was co-funded by the HBP during the Ramp-up Phase. This page is kept for reference but will no longer be updated.
Deflect is a C++ library to develop applications that can send and receive pixel streams from other Deflect-based applications, for example DisplayCluster. The following applications are provided which make use of the streaming API:
DesktopStreamer: A small utility that allows the user to stream the desktop.
SimpleStreamer: A simple example to demonstrate streaming of an OpenGL application.
The development of SCOUT was co-funded by the HBP during the Ramp-up Phase. This page is kept for reference but will no longer be updated.
SCOUT is a structure-aware method for prefetching data along interactive spatial query sequences. Given the user input, which is a spatial range query sequence representing the structure explored (interactively) by the user, and the spatial dataset to be queried, SCOUT reduces the query response time by prefetching the data along the query sequence.
Similarly to FLAT, both the query ranges in the query sequence and the spatial objects should be represented using a minimum bounding rectangle.
SCOUT outperforms the related prefetching techniques (e.g., Straight Line Extrapolation or Hilbert prefetching) with high prefetching accuracy, which is translated to one order of magnitude speedup.
Date of release
March 2015
Version of software
1.0
Version of documentation
1.0
Software available
Collaboratory, integrated in and part of BBP SDK tool set
The development of RTNeuron in the HPAC Platform was co-funded by the HBP during the second project phase (SGA1). This page is kept for reference but will no longer be updated.
RTNeuron is a scalable real-time rendering tool for the visualisation of neuronal simulations based on cable models. Its main utility is twofold: the interactive visual inspection of structural and functional features of the cortical column model and the generation of high quality movies and images for presentations and publications. The package provides three main components:
A high level C++ library.
A Python module that wraps the C++ library and provides additional tools.
The Python application script rtneuron-app.py
A wide variety of scenarios is covered by rtneuron-app.py. In case the user needs a finer control of the rendering, such as in movie production or to speed up the exploration of different data sets, the Python wrapping is the way to go. The Python wrapping can be used through an IPython shell started directly from rtneuron-app.py or importing the module rtneuron into own Python programs. GUI overlays can be created for specific use cases using PyQt and QML.
RTNeuron is available on the pilot system JULIA and on JURECA as environment module.
RTNeuron in aixCAVENeuron rendered by RTNeuronVisual representation of cell dyesSimulation playbackInteractive circuit slicingConnection browsing
Date of release
February 2018
Version of software
2.13.0
Version of documentation
2.13.0
Software available
https://developer.humanbrainproject.eu/docs/projects/RTNeuron/2.11/index.html; Open sourcing scheduled for June 2018
The development of FLAT was co-funded by the HBP during the Ramp-up Phase. This page is kept for reference but will no longer be updated.
FLAT is a spatial indexing tool, which enables scalable range queries on (3D) spatial datasets. Given the user input, which should be a query range, and the dataset to be queried, FLAT returns all the objects that intersect with the query range.
In particular, both the query ranges and the spatial objects should be represented using minimum bounding rectangle, which is the geometry approximation bounding the underlying spatial object.
FLAT outperforms the state-of-the-art spatial indexing techniques (e.g. R-trees, grid file) on extremely dense datasets.
Date of release
March 2015
Version of software
1.0
Version of documentation
1.0
Software available
Collaboratory, integrated and part of BBP SDK tool set
This website describes the results of the “High Performance Analytics and Computing” (HPAC) Platform of the Human Brain Project (HBP) from the first three project phases (Ramp-up Phase 10/2013-03/2016, SGA1 04/2016-03/2018 and SGA2 04/2018-03/2020).
Due to a major project-internal reorganisation, this website will no longer be updated after March 2020.
More recent information can be found on humanbrainproject.eu and ebrains.eu.
Information about the Fenix Research Infrastructure and the ICEI project, including resource access, are available on their website.
Follow EBRAINS Computing Services@HBPHighPerfComp and Fenix RI@Fenix_RI_eu on Twitter to learn about the most recent developments and to get to know about upcoming opportunities for calls and collaborations!
Science has driven the development of the NEST simulator for the past 20 years. Originally created to simulate the propagation of synfire chains using single-processor workstations, we have pushed NEST’s capabilities continuously to address new scientific questions and computer architectures. Prominent examples include studies on spike-timing dependent plasticity in large simulations of cortical networks, the verification of mean-field models, models of Alzheimer’s and Parkinson’s disease and tinnitus. Recent developments include a significant reduction in memory requirements, as demonstrated by a record-breaking simulation of 1.86 billion neurons connected by 11.1 trillion synapses on the Japanese K supercomputer, paving the way for brain-scale simulations.
