Description

This PR adds a check for the single node experiment
- The single_node variant [default=True] ONLY asserts that the given experiment must run on 1 node
- This check is enforced in the determine_allocation method of the allocation modifier. If single node is enabled and the experiment requires/requests more than 1 node, the ramble setup throws an error
- strong/weak scaling modes are decoupled from the single node mode (it's possible to scale on a single node)
- An experiment trying to run on more than one node must explicitly specify ~single_node

Take 2:

• We add an integer variant max_node_limit to the system specs (lib/benchpark/system.py) which is the max number of nodes allowed for an experiment on that system instantiation. Default value 1, value of 0 means no limits
• In the experiment setup (lib/benchpark/experiment.py), we add a filter clause '{n_nodes} > 0 and {n_nodes} <= {max_node_limit}'.
• The exclude clause filters all experiments that require more than max_node_limit nodes during ramble setup. Currently, it's not an error if zero experiments satisfy the max_node_limit

./bin/benchpark system init --dest=tioga llnl-elcapitan rocm=5.5.1 compiler=cce max_node_limit=1
./bin/benchpark experiment init --dest ./saxpy saxpy +openmp~cuda~rocm caliper=mpi,time
./bin/benchpark setup ./saxpy ./tioga workspace/

Dependencies: FIXME:Add a list of any dependencies.

(Potentially) Fixes #492

Type of Change

• { } Adding a system, benchmark, or experiment
• { } Modifying an existing system, benchmark, or experiment
• { } Documentation update
• { } Build/CI update
• { } Benchpark core functionality

Checklist:

If adding/modifying a system:

• { } Create a new directory for the system and a new system.py file
• { } Add a new dry run unit test in .github/workflows
• { } System appears in System Specifications table in docs catalogue section

If adding/modifying a benchpark:

• { } Add a new application.py and (maybe) package.py under a new directory
  for this benchmark
• { } Configure an experiment
• { } Benchmark appears in Benchmarks and Experiments table in docs catalogue
  section

If adding/modifying a experiment:

• { } Extend experiment.py under existing directory for specific benchmark
• { } Define a single node and multi-node experiments

If adding/modifying core functionality:

• { } Update docs
• { } Update .github/workflows and .gitlab/ci unit tests (if needed)