Solver options via params argument (#30)

* add a params argument to pass solver options

* add test

CHANGELOG.md

@@ -14,7 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Make `options` field optional [#22](https://github.com/RelationalAI/SolverAPI.jl/pull/22)
   - Remove `names` field in results [#20](https://github.com/RelationalAI/SolverAPI.jl/pull/20)
   - Update format to use JSON vector for relational appl constraint
-  args [#21](https://github.com/RelationalAI/SolverAPI.jl/pull/21)
+    args [#21](https://github.com/RelationalAI/SolverAPI.jl/pull/21)
 
 ## [0.2.2]
 

src/SolverAPI.jl

@@ -177,7 +177,13 @@ deserialize(body::String) = deserialize(Vector{UInt8}(body))
 
 # Internal version of `solve`. We do this to make handling keyword
 # arguments easier.
-function _solve(fn, json::Request, solver::MOI.AbstractOptimizer; kw...)
+function _solve(
+    fn,
+    json::Request,
+    solver::MOI.AbstractOptimizer,
+    params::Dict{Symbol,Any};
+    kw...,
+)
     errors = validate(json)
     isempty(errors) || return response(; errors)
 
@@ -191,9 +197,10 @@ function _solve(fn, json::Request, solver::MOI.AbstractOptimizer; kw...)
 
     try
         options = if haskey(json, :options)
-            json.options
+            # Copy the JSON to make it into a `Dict{Symbol,Any}`.
+            merge(copy(json.options), params)
         else
-            JSON3.Object()
+            params
         end
 
         set_options!(model, options)
@@ -228,8 +235,8 @@ function _solve(fn, json::Request, solver::MOI.AbstractOptimizer; kw...)
         MOI.empty!(model)
     end
 end
-_solve(fn, request::Dict, solver::MOI.AbstractOptimizer; kw...) =
-    _solve(fn, JSON3.read(JSON3.write(request)), solver; kw...)
+_solve(fn, request::Dict, solver::MOI.AbstractOptimizer, params::Dict{Symbol,Any}; kw...) =
+    _solve(fn, JSON3.read(JSON3.write(request)), solver, params; kw...)
 
 """
     solve([fn], request::Request, solver::MOI.AbstractOptimizer; <kwargs>)::Response
@@ -244,22 +251,27 @@ gracefully and included in `Response`.
     the `MOI.ModelLike` model and should return `Nothing`.
   - `request`: A `SolverAPI.Request` specifying the optimization problem.
   - `solver`: A `MOI.AbstractOptimizer` to use to solve the problem.
+  - `params = Dict{Symbol,Any}()`: Parameters to pass to the
+    solver. This can be used with/instead of the `options` field in
+    `request`.
 
 ## Keyword Args
 
   - `use_indicator=true`: Whether to use indicator constraints.
   - `numerical_type=Float64`: The numerical type to use for the solver.
 """
 function solve(
-    fn,
+    fn::Function,
     request,
-    solver;
+    solver,
+    params = Dict{Symbol,Any}();
     use_indicator::Bool = true,
     numerical_type::Type{<:Real} = Float64,
 )
-    return _solve(fn, request, solver; use_indicator, numerical_type)
+    return _solve(fn, request, solver, params; use_indicator, numerical_type)
 end
-solve(request, solver; kw...) = solve(model -> nothing, request, solver; kw...)
+solve(request, solver, params = Dict{Symbol,Any}(); kw...) =
+    solve(model -> nothing, request, solver, params; kw...)
 
 """
     print_model(request::Request; <kwargs>)::String
@@ -414,7 +426,7 @@ function validate(json::Request)#::Vector{Error}
 end
 
 # Set solver options.
-function set_options!(model::MOI.ModelLike, options::JSON3.Object)#::Nothing
+function set_options!(model::MOI.ModelLike, options::Dict{Symbol,Any})#::Nothing
     if MOI.supports(model, MOI.TimeLimitSec())
         # Set time limit, defaulting to 5min.
         MOI.set(model, MOI.TimeLimitSec(), Float64(get(options, :time_limit_sec, 300.0)))

test/all_tests.jl

@@ -92,6 +92,35 @@ end
     end
 end
 
+@testitem "solve - params" setup = [SolverSetup] begin
+    import JSON3
+    import HiGHS
+
+    using SolverAPI
+
+    tiny_min = JSON3.read(
+        JSON3.write(
+            Dict(
+                "version" => "0.1",
+                "sense" => "min",
+                "variables" => ["x"],
+                "constraints" => [["==", "x", 1], ["Int", "x"]],
+                "objectives" => ["x"],
+            ),
+        ),
+    )
+
+    # We can pass options to the solver via `params` as well. The
+    # `solver` key will be ignored.
+    result = solve(
+        tiny_min,
+        HiGHS.Optimizer(),
+        Dict{Symbol,Any}(:time_limit_sec => 0, :presolve => "off", :solver => "highs"),
+    )
+
+    @test result["termination_status"] == "TIME_LIMIT"
+end
+
 @testitem "errors" setup = [SolverSetup] begin
     using SolverAPI
     import JSON3