Solution Output
The .sol file
Following the AMPL solver convention, solving a positional .nl file
writes a sibling <stub>.sol next to it — pounce problem.nl
produces problem.sol. The file carries the primal x and dual
lambda blocks plus an objno line with the AMPL solve_result_num,
so AMPL (or any .sol reader) can pull the solution back:
pounce problem.nl # writes problem.sol
pounce problem.nl --sol-output out.sol # write to an explicit path
pounce problem.nl --no-sol # skip the .sol write
A .sol is written even when the solve fails, so the
solve_result_num is always recoverable. Built-in problems
(--problem …) have no .nl stub, so they only produce a .sol
when --sol-output is given explicitly.
Choosing an output format
| You want… | Use |
|---|---|
| AMPL / Pyomo to read the result back | the .sol file (default) |
| A structured, schema-versioned report for tooling | --json-output (see JSON Solve Report) |
| Just the console summary | --no-sol |
The .sol and JSON outputs are not exclusive — you can request both
in the same run.