Remove unneeded get_cb_solution and associated cache

README.md

@@ -160,8 +160,6 @@ function my_callback_function(cb_data)
     @assert XPRSgetdblattrib(prob, XPRS_BESTBOUND, p_bound) == 0
     rel_gap = abs((p_obj[] - p_bound[]) / p_obj[])
     @info "Relative gap = $rel_gap"
-    # Before querying `callback_value`, you must call:
-    Xpress.get_cb_solution(unsafe_backend(model), cb_data.model)
     x_val = callback_value(cb_data, x)
     y_val = callback_value(cb_data, y)
     # You can submit solver-independent MathOptInterface attributes such as

src/MOI/MOI_callbacks.jl

@@ -61,23 +61,6 @@ function MOI.set(model::Optimizer, ::CallbackFunction, f::Function)
     return
 end
 
-function get_cb_solution(model::Optimizer, model_inner::XpressProblem)
-    model.callback_cached_solution = _reset_cached_solution(
-        model.callback_cached_solution,
-        length(model.variable_info),
-        length(model.affine_constraint_info),
-    )
-    ret = XPRSgetlpsol(
-        model_inner,
-        model.callback_cached_solution.variable_primal,
-        model.callback_cached_solution.linear_primal,
-        model.callback_cached_solution.linear_dual,
-        model.callback_cached_solution.variable_dual,
-    )
-    _check(model_inner, ret)
-    return
-end
-
 function _load_existing_cuts(model::Optimizer, cb_data::CallbackData)
     if isempty(model.cb_cut_data.cutptrs)
         return false
@@ -126,7 +109,6 @@ function default_moi_callback(model::Optimizer)
         if pInt[] > 1
             return
         end
-        get_cb_solution(model, cb_data.model)
         if model.heuristic_callback !== nothing
             model.callback_state = CB_HEURISTIC
             model.heuristic_callback(cb_data)
@@ -159,11 +141,14 @@ end
 
 function MOI.get(
     model::Optimizer,
-    ::MOI.CallbackVariablePrimal{CallbackData},
+    attr::MOI.CallbackVariablePrimal{CallbackData},
     x::MOI.VariableIndex,
 )
-    column = _info(model, x).column
-    return model.callback_cached_solution.variable_primal[column]
+    c = _info(model, x).column - 1
+    xP = Ref{Cdouble}()
+    ret = XPRSgetcallbacksolution(attr.callback_data.model, C_NULL, xP, c, c)
+    _check(model, ret)
+    return xP[]
 end
 
 function callback_exception(model::Optimizer, cb, err::Exception)
@@ -314,3 +299,6 @@ function MOI.submit(
 end
 
 MOI.supports(::Optimizer, ::MOI.HeuristicSolution{CallbackData}) = true
+
+# Kept for backward compatibility with v0.18
+get_cb_solution(::Optimizer, ::XpressProblem) = nothing

src/MOI/MOI_wrapper.jl

@@ -248,7 +248,6 @@ mutable struct Optimizer <: MOI.AbstractOptimizer
     backward_sensitivity_cache::Union{Nothing,SensitivityCache}
 
     # Callback fields.
-    callback_cached_solution::Union{Nothing,CachedSolution}
     cb_cut_data::CallbackCutData
     callback_state::CallbackState
     cb_exception::Union{Nothing,Exception}
@@ -373,7 +372,6 @@ function MOI.empty!(model::Optimizer)
     # solve_method
     model.forward_sensitivity_cache = nothing
     model.backward_sensitivity_cache = nothing
-    model.callback_cached_solution = nothing
     model.cb_cut_data = CallbackCutData(false, XPRScut[])
     model.callback_state = CB_NONE
     model.cb_exception = nothing
@@ -405,7 +403,6 @@ function MOI.is_empty(model::Optimizer)
            model.termination_status == MOI.OPTIMIZE_NOT_CALLED &&
            model.primal_status == MOI.NO_SOLUTION &&
            model.dual_status == MOI.NO_SOLUTION &&
-           model.callback_cached_solution === nothing &&
            model.callback_state == CB_NONE &&
            model.cb_exception === nothing &&
            model.lazy_callback === nothing &&

test/test_MOI_wrapper.jl

@@ -1155,7 +1155,6 @@ function test_callback_function_LazyConstraint()
     global generic_lazy_called = false
     function callback_function(cb_data)
         push!(cb_calls, 1)
-        Xpress.get_cb_solution(model, cb_data.model)
         x_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), x)
         y_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), y)
         if y_val - x_val > 1 + 1e-6
@@ -1196,7 +1195,6 @@ function test_callback_function_UserCut()
             if pInt[] > 1
                 return
             end
-            Xpress.get_cb_solution(model, cb_data.model)
             terms = MOI.ScalarAffineTerm{Float64}[]
             accumulated = 0.0
             for (i, xi) in enumerate(x)
@@ -1235,7 +1233,6 @@ function test_callback_function_HeuristicSolution()
             if pInt[] > 1
                 return
             end
-            Xpress.get_cb_solution(model, cb_data.model)
             x_vals =
                 MOI.get.(model, MOI.CallbackVariablePrimal(cb_data), x)
             @test MOI.submit(
@@ -1547,7 +1544,6 @@ end
 function test_callback_function_nothing()
     model, x, y = callback_simple_model()
     function callback_function(cb_data)
-        Xpress.get_cb_solution(model, cb_data.model)
         x_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), x)
         y_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), y)
         if y_val - x_val > 1 + 1e-6
@@ -1583,7 +1579,6 @@ end
 function test_callback_function_replace()
     model, x, y = callback_simple_model()
     function callback_function(cb_data)
-        Xpress.get_cb_solution(model, cb_data.model)
         x_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), x)
         y_val = MOI.get(model, MOI.CallbackVariablePrimal(cb_data), y)
         if y_val - x_val > 1 + 1e-6
@@ -2332,6 +2327,12 @@ function test_InterruptException()
     return
 end
 
+function test_get_cb_solution()
+    model = Xpress.Optimizer()
+    @test Xpress.get_cb_solution(model, model.inner) === nothing
+    return
+end
+
 end  # TestMOIWrapper
 
 TestMOIWrapper.runtests()