🔌 Solver wrapper protocol
RamParILS communicates with the target algorithm via a simple subprocess protocol.
📥 Invocation
The solver is invoked as a shell command:
<algo> <instance> <cutoff_time> -param1 val1 -param2 val2 …
<algo>— the command from the scenario’salgofield (passed tosh -c)<instance>— path to the instance file<cutoff_time>— per-run time limit in seconds-param valpairs — active parameters in alphabetical order
The complete command is passed to sh -c. Scenario files and parameter values
must therefore be trusted, and wrappers should avoid paths or values that need
shell quoting.
Example:
ruby /path/to/saps_wrapper.rb /data/inst1.cnf 5.0 -alpha 1.189 -rho 0.5 -ps 0.1 -wp 0.03
📤 Output
The solver must print a result line to stdout:
#%# RamParIls #%# <status>, <runtime>, <quality>
| Field | Values | Description |
|---|---|---|
status | text | Outcome of the run; stored verbatim in the cache |
runtime | float | Actual runtime in seconds (capped to cutoff_time) |
quality | float | Numeric cost to minimise when run_obj: quality |
The result line may appear anywhere in stdout; other output is ignored.
RamParILS stores status for reporting but does not use it when scoring.
The wrapper must therefore encode timeouts, crashes, and unsolved cases as an
appropriate runtime or quality penalty.
If no valid result line is found, the status becomes UNKNOWN, runtime is set
to cutoff_time, and quality is set to 10000000. UNKNOWN results are not
written to the persistent cache.
🧪 Examples
Successful run:
#%# RamParIls #%# OK, 1.23, 0.0
Timeout:
#%# RamParIls #%# TIMEOUT, 5.0, 0.0
🦴 Minimal wrapper skeleton
#!/usr/bin/env ruby
instance, cutoff, *params = ARGV
# ... run your solver here ...
puts "#%# RamParIls #%# OK, #{runtime}, 0.0"