Add get_quadratic_constraint and fix getting of quadratic function (#24)

* Add get_quadratic_constraint and fix getting of quadratic function

* Enable getting of interval sets

Author: odow

src/constraints/scalaraffine.jl

@@ -137,7 +137,7 @@ function MOI.get(m::LinQuadOptimizer, ::MOI.ConstraintSet, c::LCI{S}) where S <:
     S(rhs+m.constraint_constant[m[c]])
 end
 
-MOI.canget(::LinQuadOptimizer, ::MOI.ConstraintSet, ::Type{LCI{IV}}) = false
+MOI.canget(::LinQuadOptimizer, ::MOI.ConstraintSet, ::Type{LCI{IV}}) = true
 function MOI.get(m::LinQuadOptimizer, ::MOI.ConstraintSet, c::LCI{IV})
     lowerbound, upperbound = get_range(m, m[c])
     IV(lowerbound+m.constraint_constant[m[c]], upperbound + m.constraint_constant[m[c]])

src/constraints/scalarquadratic.jl

@@ -103,7 +103,7 @@ end
 
 MOI.canget(m::LinQuadOptimizer, ::MOI.ConstraintSet, ::Type{QCI{S}}) where S <: Union{LE, GE, EQ} = true
 function MOI.get(m::LinQuadOptimizer, ::MOI.ConstraintSet, c::QCI{S}) where S <: Union{LE, GE, EQ}
-    rhs = get_rhs(m, m[c])
+    rhs = get_quadratic_rhs(m, m[c])
     S(rhs)
 end
 
@@ -118,8 +118,8 @@ function MOI.get(m::LinQuadOptimizer, ::MOI.ConstraintFunction, c::QCI{<: LinSet
     # TODO more efficiently
     colidx, coefs, Q = get_quadratic_constraint(m, m[c])
     affine_terms = map(
-        (v,c)->MOI.ScalarAffineTerm{Float64}(c,v),
-        m.variable_references[colidx+1],
+        (v,c)->MOI.ScalarAffineTerm{Float64}(c, m.variable_references[v]),
+        colidx,
         coefs
     )
     rows = rowvals(Q)
@@ -135,4 +135,4 @@ function MOI.get(m::LinQuadOptimizer, ::MOI.ConstraintFunction, c::QCI{<: LinSet
         end
     end
     Quad(affine_terms, quadratic_terms, 0.0) # constant was moved into set
-end
+end

src/solver_interface.jl

@@ -351,6 +351,13 @@ Where `Q` represents the matrix in CSC format.
 """
 function get_quadratic_constraint end
 
+"""
+    get_quadratic_constraint(m, row::Int)::Float64
+
+Get the right hand-side term of quadratic constraint in row `row` in model `m`.
+"""
+function get_quadratic_rhs end
+
 """
     set_linear_objective!(m, cols::Vector{Int}, coefs::Vector{Float64})::Void