The National Center for Multiscale Modeling of Biological Systems (MMBioS), and the National Resource for Biomedical Supercomputing (NRBSC) at the Pittsburgh Supercomputing Center (PSC) are soliciting proposals for computer time on Anton, a special-purpose supercomputer for molecular dynamics (MD) simulation designed by D. E. Shaw Research (DESRES). A 512-node Anton machine is currently available and in production use at the PSC. The machine has been made available without cost by DESRES for non-commercial research use by universities and other not-for-profit institutions, and is hosted by NRBSC. Operational funding is provided by NIGMS through MMBioS, a joint effort between the University of Pittsburgh, PSC, Carnegie Mellon University, and the Salk Institute.
To qualify for an allocation on Anton, the principal investigator (PI) must be a faculty or staff member at a U.S. academic or non-profit research institution and must have the appropriate level of authority and responsibility to direct the project supported by the allocation. A graduate student or postdoctoral researcher may not be a PI, but a qualified advisor may apply for an allocation on her or his behalf. Furthermore, each investigator can serve as a PI for only a single application for computer time on Anton. PIs who previously had an allocation on Anton at NRBSC are strongly encouraged to apply but are required to provide a detailed (2-3 page) progress report of their past work on the Anton machine at NRBSC. Repeat applications unaccompanied by a progress report will not be considered.
The remainder of this Request for Proposals (RFP) describes the intended focus of solicited projects, outlines simulation requirements, offers proposal preparation instructions, and explains the proposal review process.
Anton enables scientists to perform MD simulations of biomolecular systems nearly two orders of magnitude faster than the previous state of the art (see the Estimating Requested Simulation Resources section). To maximize the benefit of Anton to the scientific community, proposed projects should focus exclusively on questions that will be greatly advanced by multi-microsecond MD simulations. Special emphasis should be on the need for long continuous trajectories rather than a sampling of many short ones. Further, investigators should explain why such long timescales are necessary and important for the molecular system and scientific question under consideration. Proposals to run only a large number of shorter simulations will receive a lower ranking in the review process.
Anton uses specialized hardware to perform molecular dynamics simulations orders of magnitude faster than general-purpose hardware running traditional MD software (see References 1-3 below). Importantly, Anton does not run Desmond, AMBER, NAMD, GROMACS, or any other MD simulation software package, although it uses a Desmond structure (DMS) file as an initial input and its trajectory output is compatible with Desmond’s (DTR files). Each simulation must be built, using tools available at NRBSC, specifically for Anton.
Anton is designed primarily to accelerate classical MD simulations of biomolecular systems with periodic boundary conditions and explicit solvent. To make best use of the available computational resources, consideration will be given only to applicants whose projects satisfy the criteria outlined below. Investigators who have questions regarding the suitability of their proposed simulations are encouraged to contact firstname.lastname@example.org to discuss their planned project before submitting their proposal.
- Simulations must be standard MD runs in the constant NVE, constant NVT (isothermal), and constant NPT (isothermal, isobaric) ensembles. Simulations may use Berendsen or Nose-Hoover thermostats, and may use Berendsen or MTK barostats with isotropic or semi-isotropic scaling. Simulation conditions may include the specification of a uniform constant applied electric field. Position restraints, on a per atom basis, are allowed. Enhanced sampling is also available in three basic forms: (i) simulated tempering with the Nose-Hoover thermostat, (ii) application of a restraint between the centers of mass of groups of atoms, and (iii) application of up to two distinct conformation restraints, each based on the calculation of RMSD (root mean squared deviation) with respect to atomic positions of a given reference structure. For restraints in both (ii) and (iii), equilibria and spring constants can be varied during a simulation according to a schedule. The total number of atoms involved in either the distance restraint or the RMSD restraints may not exceed 2048.
- The simulation cell must have only right angles (i.e., it must be a cubic or orthorhombic box), and must be a minimum of 45 Angstroms on each side. Furthermore, the ratio of the largest side to smallest side must not exceed 1.5:1. Applicants with systems shaped such that one dimension of the simulation cell is much larger than the others should contact email@example.com before submitting a proposal.
- Proposed simulations must use recent variants of the following standard biomolecular force fields: CHARMM (e.g., CHARMM22, CHARMM27 - including CMAP corrections, and CHARMM36), AMBER (e.g., AMBER99, AMBER99SB, AMBER03), or OPLS (e.g., OPLS-AA/L). Modified versions of the CHARMM and AMBER force fields, based on published research by DESRES, are also acceptable (and available through the simulation setup tools). Water should be modeled with the SPC, TIP3P, or TIP4P models, or their variants.
- Chemical systems proposed for simulation must contain between 20,000 and 150,000 atoms (including solvent atoms). Chemical systems proposed for simulation must consist of some combination of protein, DNA, RNA, lipids, water, and standard ions. Investigators who wish to use custom parameters or molecules that are not included in the standard distribution of the supported force fields (see 3 above) should contact firstname.lastname@example.org to discuss the suitability of their simulations before submitting their proposal.
Applicants may refer to the table below, with benchmarks for a number of systems of various sizes, to estimate the amount of machine time required for their project. The actual achievable simulation times, however, may vary even for different molecular systems of similar size. No more than a total of 8.14 machine-days (100,000 node hours) will be allocated to any one principal investigator. It is anticipated that 10 to 20 allocations will be made at or near 100,000 node-hours, and 30 to 40 allocations will be made at or near 50,000 node-hours. Applicants are encouraged to target their requested resources at one of these levels. Note that simulations on Anton will run on all 512 nodes.
For more details regarding Anton, please see the References.
|Chemical system (PDB ID)||Number of atoms||Approximate performance (microseconds/machine-day)*|
*All simulations used 2.5-femtosecond time steps with long-range interactions evaluated at every other time step and a Berendsen thermostat applied every 100 time steps. Performance was measured on a 512-node Anton machine like the one hosted by the NRBSC.
Structure of Proposal
Proposals should be two to six pages in length, not including references. PIs who previously received an allocation on Anton at NRBSC must also provide a separate 2-3 page progress report demonstrating their successful use of Anton to produce high-impact scientific results. In addition, applicants may submit up to two additional supporting documents (e.g., published papers) in PDF format on the submission page. The main proposal document must have the following sections:
- Summary of the project, including descriptive title of proposed research (400 words maximum).
- Name, address, email, and telephone number of Principal Investigator(s).
- Background information (1 page maximum). Investigators should include sufficient background information on the research field to allow reviewers to judge the scientific merit of the proposed research.
- Scientific Objectives to be accomplished on Anton (2 pages maximum). Investigators should clearly explain why long-timescale MD simulations are important for the planned project (see the Intended Focus of Proposed Projects section for more details). Applicants should also clearly explain the scientific impact of their proposed project.
- Project Feasibility (2 page maximum). Applicants must clearly and explicitly address all four points outlined in the Simulation Requirements section of this RFP, providing all necessary details regarding their proposed simulations and the expertise of their research team members (including prior experience running MD simulations) to ensure that the proposed simulations can be successfully completed on Anton.
- Requested Resources (1 page maximum). Investigators must clearly state and provide justification for the number of Anton node-hours requested for their project subject to the limits given in Estimating Requested Simulation Resources. The number of node-hours is 512 times 24 times the number of machine-days. The justification should provide strong scientific arguments as to why the length and number of proposed simulation runs will be both sufficient and necessary to achieve the stated scientific objectives. Please refer to the Estimating Requested Simulation Resources section for benchmarks to facilitate estimation of requested resources. No more than a total of 8.14 machine-days (100,000 node-hours) can be requested per PI.
Important Dates and Proposal Review ProcessProposal submission is closed
Proposals will initially be assessed for technical feasibility by NRBSC and PSC staff (see the Simulation Requirements section) and will then be reviewed by a peer committee to be convened by the National Research Council. Resource allocations will be made by NRBSC following the recommendations of the National Research Council. Final allocation decisions are expected in September 2013. Resources are expected to be made available starting in October 2013.
Proposals will be ranked based on the scientific merit of the proposed research and the strength of the justification for the requested resources. In addition, proposals by PIs that previously received an allocation on Anton at NRBSC will need to demonstrate that the scientific outcomes from the previous award(s) justify another award. At least 25% of the total allocated time will be reserved for PIs that have not previously had an allocation on Anton at NRBSC. Since only a limited number of allocations will be available on Anton, a successful proposal will clearly state how access to Anton will facilitate breakthrough science.
For general questions regarding this RFP, or to discuss feasibility and technical aspects of projects, please contact email@example.com.
 Extending the Generality of Molecular Dynamics Simulations on a Special-
Purpose Machine, D. P. Scarpazza et al., Proceedings of the 27th IEEE International
Parallel and Distributed Processing Symposium (IPDPS), Boston, MA: IEEE
Computer Society (2013)
 Millisecond-Scale Molecular Dynamics Simulations on Anton, D. E. Shaw et al., Proceedings of the ACM/IEEE Conference on Supercomputing (SC09), Portland, Oregon (2009)
 Anton, A Special-Purpose Machine for Molecular Dynamics Simulation, D. E. Shaw et al., Proceedings of the 34th Annual International Symposium on Computer Architecture (ISCA ‘07), (2007)