MOOSE System Requirements Specification
This template follows INL template TEM-135, "IT System Requirements Specification".
This document serves as an addendum to Framework System Requirements Specification and captures information for SRS specific to the MOOSE application.
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Introduction
System Purpose
MOOSE is a tool for solving complex coupled Multiphysics equations using the finite element method. MOOSE uses an object-oriented design to abstract data structure management, parallelism, threading and compiling while providing an easy to use interface targeted at engineers that may not have a lot of software development experience. MOOSE will require extreme scalability and flexibility when compared to other FEM frameworks. For instance, MOOSE needs the ability to run extremely complex material models, or even third-party applications within a parallel simulation without sacrificing parallelism. This capability is in contrast to what is often seen in commercial packages, where custom material models can limit the parallel scalability, forcing serial runs in the most severe cases. When comparing high-end capabilities, many MOOSE competitors target modest-sized clusters with just a few thousand processing cores. MOOSE, however, will be required to routinely executed on much larger clusters with scalability to clusters available in the top 500 systems (top500.org). MOOSE will also be targeted at smaller systems such as high-end laptop computers.
The design goal of MOOSE is to give developers ultimate control over their physical models and applications. Designing new models or solving completely new classes of problems will be accomplished by writing standard C++ source code within the framework's class hierarchy. Scientists and engineers will be free to implement completely new algorithms using pieces of the framework where possible, and extending the framework's capabilities where it makes sense to do so. Commercial applications do not have this capability, and instead opt for either a more rigid parameter system or a limited application-specific metalanguage.
System Scope
MOOSE's scope is to provide a set of interfaces for building FEM simulations. Abstractions to all underlying libraries are provided.
Solving coupled problems where competing physical phenomena impact one and other in a significant nonlinear fashion represents a serious challenge to several solution strategies. Small perturbations in strongly-coupled parameters often have very large adverse effects on convergence behavior. These adverse effects are compounded as additional physics are added to a model. To overcome these challenges, MOOSE employs three distinct yet compatible systems for solving these types of problems.
First, an advanced numerical technique called the Jacobian-Free Newton-Krylov (JFNK) method is employed to solve the most fully-coupled physics in an accurate, consistent way. An example of this would be the effect of temperature on the expansion or contraction of a material. While the JFNK numerical method is very effective at solving fully-coupled equations, it can also be computationally expensive. Plus, not all physical phenomena in a given model are truly coupled to one another. For instance, in a reactor, the speed of the coolant flow may not have any direct effect on the complex chemical reactions taking place inside the fuel rods. We call such models "loosely-coupled". A robust, scalable system must strike the proper balance between the various modeling strategies to avoid performing unnecessary computations or incorrectly predicting behavior in situations such as these.
MOOSE's Multiapp system will allow modelers to group physics into logical categories where MOOSE can solve some groups fully-coupled and others loosely-coupled. The Multiapp system goes even further by also supporting a "tightly-coupled" strategy, which falls somewhere between the "fully-coupled" and "loosely-coupled" approaches. Several sets of physics can then be linked together into logical hierarchies using any one of these coupling strategies, allowing for several potential solution strategies. For instance, a complex nuclear reactor model might consist of several tightly-coupled systems of fully-coupled equations.
Finally, MOOSE's Transfers system ties all of the physics groups contained within the Multiapp system together and allows for full control over the flow of information among the various groups. This capability bridges physical phenomena from several different complementary scales simultaneously. When these three MOOSE systems are combined, myriad coupling combinations are possible. In all cases, the MOOSE framework handles the parallel communication, input, output and execution of the underlying simulation. By handling these computer science tasks, the MOOSE framework keeps modelers focused on doing research.
MOOSE innovates by building advanced simulation capabilities on top of the very best available software technologies in a way that makes them widely accessible for innovative research. MOOSE is equally capable of solving small models on common laptops and the very biggest FEM models ever attempted—all without any major changes to configuration or source code. Since its inception, the MOOSE project has focused on both developer and computational efficiency. Improved developer efficiency is achieved by leveraging existing algorithms and technologies from several leading open-source packages. Additionally, MOOSE uses several complementary parallel technologies (both the distributed-memory message passing paradigm and shared-memory thread-based approaches are used) to lay an efficient computational foundation for development. Using existing open technologies in this manner helps the developers reduce the scope of the project and keeps the size of the MOOSE code base maintainable. This approach provides users with state-of-the-art finite element and solver technology as a basis for the advanced coupling and solution strategies mentioned previously.
MOOSE's developers work openly with other package developers to make sure that cutting-edge technologies are available through MOOSE, providing researchers with competitive research opportunities. MOOSE maintains a set of objects that hide parallel interfaces while exposing advanced spatial and temporal coupling algorithms in the framework. This accessible approach places developmental technology into the hands of scientists and engineers, which can speed the pace of scientific discovery.
System Overview
System Context
MOOSE is a command-line driven application. This is typical for high-performance software that is designed to run across several nodes of a cluster system. As such, all of the usage of the software is through any standard terminal program generally available on all supported operating systems. Similarly, for the purpose of interacting through the software, there is only a single user, "the user", which interacts with the software through the command-line. MOOSE does not maintain any back-end database or interact with any system daemons. It is an executable, which may be launched from the command line and writes out various result files as it runs.
System Functions
Since MOOSE is a command-line driven application, all functionality provided in the software is operated through the use of standard UNIX command line flags and the extendable MOOSE input file. MOOSE is completely extendable so individual design pages should be consulted for specific behaviors of each user-defined object.
User Characteristics
Framework Developers: These are the core developers of the framework. They will be responsible for following and enforcing the appropriate software development standards. They will be responsible for designing, implementing and maintaining the software.
Developers: A Scientist or Engineer that utilizes the framework to build their own application. This user will typically have a background in modeling and simulation techniques and/or numerical analysis but may only have a limited skill-set when it comes to object-oriented coding and the C++ language. This is our primary focus group. In many cases these developers will be encouraged to give their code back to the framework maintainers.
Analysts: These are users that will run the code and perform various analysis on the simulations they perform. These users may interact with developers of the system requesting new features and reporting bugs found and will typically make heavy use of the input file format.
Assumptions and Dependencies
The MOOSE application is developed using MOOSE and is based on various modules, as such the SRS for MOOSE is dependent upon the files listed at the beginning of this document. Any further assumptions or dependencies are outlined in the remainder of this section.
The software should be designed with the fewest possible constraints. Ideally the software should run on a wide variety of evolving hardware so it should follow well-adopted standards and guidelines. The software should run on any POSIX compliant system. The software will also make use FEM and numerical libraries that run on POSIX systems as well. The main interface for the software will be command line based with no assumptions requiring advanced terminal capabilities such as coloring and line control.
References
Definitions and Acronyms
This section defines, or provides the definition of, all terms and acronyms required to properly understand this specification.
Definitions
Verification: (1) The process of: evaluating a system or component to determine whether the products of a given development phase satisfy the conditions imposed at the start of that phase. (2) Formal proof of program correctness (e.g., requirements, design, implementation reviews, system tests) (24765:2010(E), 2010).
Acronyms
Acronym | Description |
---|---|
FEM | Finite Element Method |
INL | Idaho National Laboratory |
JFNK | Jacobian-Free Newton-Krylov |
MOOSE | Multiphysics Object Oriented Simulation Environment |
NQA-1 | Nuclear Quality Assurance Level 1 |
POSIX | Portable Operating System Interface |
SRS | Software Requirement Specification |
System Requirements
In general, the following is required for MOOSE-based development:
GCC/Clang C++17 compliant compiler (GCC @ 7.5.0, Clang @ 10.0.1 or greater)
Note: Intel compilers are not supported.
Memory: 8 GBs of RAM for optimized compilation (16 GBs for debug compilation), 2 GB per core execution
Processor: 64-bit x86 or ARM64 (specifically, Apple Silicon)
Disk: 30GB
A POSIX compliant Unix-like operating system, including the two most recent versions of MacOS and most current versions of Linux.
Git version control system
Python @ 3.7 or greater
Functional Requirements
All of the requirements for MOOSE are provided in the dependent SRS documents, please refer to the documents listed in Assumptions and Dependencies.
Usability Requirements
All of the requirements for MOOSE are provided in the dependent SRS documents, please refer to the documents listed in Assumptions and Dependencies.
Performance Requirements
All of the requirements for MOOSE are provided in the dependent SRS documents, please refer to the documents listed in Assumptions and Dependencies.
System Interfaces
All of the requirements for MOOSE are provided in the dependent SRS documents, please refer to the documents listed in Assumptions and Dependencies.
System Operations
Human System Integration Requirements
The MOOSE application is command line driven and conforms to all standard terminal behaviors. Specific human system interaction accommodations shall be a function of the end-user's terminal. MOOSE (and therefore MOOSE) does support optional coloring within the terminal's ability to display color, which may be disabled.
Maintainability
The latest working version (defined as the version that passes all tests in the current regression test suite) shall be publicly available at all times through the repository host provider.
Flaws identified in the system shall be reported and tracked in a ticket or issue based system. The technical lead will determine the severity and priority of all reported issues and assign resources at their discretion to resolve identified issues.
The software maintainers will entertain all proposed changes to the system in a timely manner (within two business days).
The core software in its entirety will be made available under the terms of a designated software license. These license terms are outlined in the LICENSE file alongside the MOOSE application source code.
Reliability
The regression test suite will cover at least 80% of all lines of code at all times. Known regressions will be recorded and tracked (see Maintainability) to an independent and satisfactory resolution.
System Modes and States
MOOSE applications normally run in normal execution mode when an input file is supplied. However, there are a few other modes that can be triggered with various command line flags as indicated here:
Command Line Flag | Description of mode |
---|---|
-i <input_file> | Normal execution mode |
--split-mesh <splits> | Read the mesh block splitting the mesh into two or more pieces for use in a subsequent run |
--use-split | (implies -i flag) Execute the simulation but use pre-split mesh files instead of the mesh from the input file |
--yaml | Output all object descriptions and available parameters in YAML format |
--json | Output all object descriptions and available parameters in JSON format |
--syntax | Output all registered syntax |
--registry | Output all known objects and actions |
--registry-hit | Output all known objects and actions in HIT format |
--mesh-only (implies -i flag) | Run only the mesh related tasks and output the final mesh that would be used for the simulation |
--start-in-debugger <debugger> | Start the simulation attached to the supplied debugger |
The list of system-modes may not be extensive as the system is designed to be extendable to end-user applications. The complete list of command line options for applications can be obtained by running the executable with zero arguments. See the command line usage.
Physical Characteristics
The MOOSE application is software only with no associated physical media. See System Requirements for a description of the minimum required hardware necessary for running the MOOSE application.
Environmental Conditions
Not Applicable
System Security
MOOSE-based applications such as MOOSE have no requirements or special needs related to system-security. The software is designed to run completely in user-space with no elevated privileges required nor recommended.
Information Management
The core framework in its entirety will be made publicly available on an appropriate repository hosting site. Day-to-day backups and security services will be provided by the hosting service. More information about MOOSE backups of the public repository on INL-hosted services can be found on the following page: GitHub Backups
Polices and Regulations
MOOSE-based applications must comply with all export control restrictions.
System Life Cycle Sustainment
MOOSE-based development follows various agile methods. The system is continuously built and deployed in a piecemeal fashion since objects within the system are more or less independent. Every new object requires a test, which in turn requires an associated requirement and design description. The MOOSE development team follows the NQA-1 standards.
Packaging, Handling, Shipping and Transportation
No special requirements are needed for packaging or shipping any media containing MOOSE source code. However, some MOOSE-based applications may be export-controlled, in which case all export control restrictions must be adhered to when packaging and shipping media.
Verification
The regression test suite will employ several verification tests using comparison against known analytical solutions, the method of manufactured solutions, and convergence rate analysis.
The MOOSE application is command-line driven. Like MOOSE, this is typical for a high-performance software that is designed to run across several nodes of a cluster system. As such, all usage of the software is through any standard terminal program generally available on all supported operating systems. Similarly, for the purpose of interacting through the software, there is only a single user, "the user", which interacts with the software through the command-line. MOOSE does not maintain any back-end database or interact with any system daemons. It is an executable, which may be launched from the command line and writes out various result files as it runs.