More documentation

Author: odow

docs/src/manual/constraints.md

@@ -614,6 +614,8 @@ con : 2 x ∈ [-4.0, -2.0]
 
 ## Modify a variable coefficient
 
+### Scalar constraints
+
 To modify the coefficients for a linear term (modifying the coefficient of a
 quadratic term is not supported) in a constraint, use
 [`set_normalized_coefficient`](@ref). To query the current coefficient, use
@@ -635,6 +637,30 @@ julia> normalized_coefficient(con, x[2])
     [`set_normalized_coefficient`](@ref) sets the coefficient of the normalized
     constraint. See [Normalization](@ref) for more details.
 
+### Vector constraints
+
+To modify the coefficients of a vector-valued constraint, use
+[`set_normalized_coefficients`](@ref).
+```jldoctest
+julia> model = Model();
+
+julia> @variable(model, x)
+x
+
+julia> @constraint(model, con, [2x + 3x, 4x] in MOI.Nonnegatives(2))
+con : [5 x, 4 x] ∈ MathOptInterface.Nonnegatives(2)
+
+julia> set_normalized_coefficients(con, x, [(1, 3.0)])
+
+julia> con
+con : [3 x, 4 x] ∈ MathOptInterface.Nonnegatives(2)
+
+julia> set_normalized_coefficients(con, x, [(1, 2.0), (2, 5.0)])
+
+julia> con
+con : [2 x, 5 x] ∈ MathOptInterface.Nonnegatives(2)
+```
+
 ## Delete a constraint
 
 Use [`delete`](@ref) to delete a constraint from a model. Use [`is_valid`](@ref)

src/constraints.jl

@@ -690,7 +690,8 @@ end
     )
 
 Set the coefficients of `variable` in the constraint `con_ref` to
-`new_coefficients`.
+`new_coefficients`, where each element in `new_coefficients` is a tuple which
+maps the row to a new coefficient.
 
 Note that prior to this step, during constraint creation, JuMP will aggregate
 multiple terms containing the same variable.

test/constraint.jl

@@ -835,8 +835,6 @@ function test_Model_change_coefficient(::Any, ::Any)
 end
 
 function test_Model_change_coefficients(::Any, ::Any)
-    model = JuMP.Model()
-    x = @variable(model)
     model = Model()
     @variable(model, x)
     @constraint(model, con, [2x + 3x, 4x] in MOI.Nonnegatives(2))