Merge 0efbb59 into a9d7e28

src/constraints.jl

@@ -372,6 +372,29 @@ function set_coefficient(constraint::ConstraintRef{Model, MOICON{F, S}},
     return
 end
 
+"""
+    value(cref::ConstraintRef)
+
+Get the primal value of this constraint in the result returned by a solver. That
+is, if `cref` is the reference of a constraint `func`-in-`set`, it returns the
+value of `func` evaluated at the value of the variables (given by
+[`value(::VariableRef)`](@ref)).
+Use [`has_values`](@ref) to check if a result exists before asking for values.
+
+## Note
+
+For scalar contraints, the constant is moved to the `set` so it is not taken
+into account in the primal value of the constraint. For instance, the constraint
+`@constraint(model, 2x + 3y + 1 == 5)` is transformed into
+`2x + 3y`-in-`MOI.EqualTo(4)` so the value returned by this function is the
+evaluation of `2x + 3y`.
+```
+"""
+function value(cref::ConstraintRef{Model, <:MOICON})
+    return reshape(MOI.get(cref.model, MOI.ConstraintPrimal(), cref),
+                   cref.shape)
+end
+
 """
     shadow_price(constraint::ConstraintRef)
 

test/generate_and_solve.jl

@@ -64,6 +64,7 @@
         @test JuMP.value(x) == 1.0
         @test JuMP.value(y) == 0.0
         @test JuMP.value(x + y) == 1.0
+        @test JuMP.value(c) == 1.0
         @test JuMP.objective_value(m) == -1.0
 
         @test JuMP.dual_status(m) == MOI.FEASIBLE_POINT
@@ -335,6 +336,12 @@
 
         @test JuMP.has_values(m)
         @test JuMP.value.(x) == [1.0 2.0; 2.0 4.0]
+        @test JuMP.value(var_psd) isa Symmetric
+        @test JuMP.value(var_psd) == [1.0 2.0; 2.0 4.0]
+        @test JuMP.value(sym_psd) isa Symmetric
+        @test JuMP.value(sym_psd) == [0.0 2.0; 2.0 3.0]
+        @test JuMP.value(con_psd) isa Matrix
+        @test JuMP.value(con_psd) == [0.0 2.0; 2.0 3.0]
 
         @test JuMP.has_duals(m)
         @test JuMP.dual(var_psd) isa Symmetric