[MOF] Begin formal JSON schema (#47)

* [MOF] Begin formal JSON schema

* More updates to the schema

* Finish Base MOI schema

* A few minor fixes

* Add nonlinear schema

* Update schema

* Add JSONSchema to validate models

* Remove Manifest file

* Add manifest to .gitignore

* Add minimum values to some integer fields

* Split functions into scalar and vector types

* Re-order top-level properties of schema

* Update field names after #49

* Add top-level `name` field and minor comment fixes

* Tidy schema

* Add (validated) example files

* Add more examples

* Fix coefficients

* Add descriptions to schema

* Add VariablePrimalStart attribute

.gitignore

@@ -1,3 +1,4 @@
 *.jl.cov
 *.jl.*.cov
 *.jl.mem
+Manifest.toml

Project.toml

@@ -0,0 +1,15 @@
+name = "MathOptFormat"
+uuid = "f4570300-c277-12e8-125c-4912f86ce65d"
+authors = ["Oscar Dowson <[email protected]"]
+version = "0.0.0"
+
+[deps]
+DataStructures = "864edb3b-99cc-5e75-8d2d-829cb0a9cfe8"
+GZip = "92fee26a-97fe-5a0c-ad85-20a5f3185b63"
+JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+JSONSchema = "7d188eb4-7ad8-530c-ae41-71a32a6d4692"
+MathOptInterface = "b8f27783-ece8-5eb3-8dc8-9495eed66fee"
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[compat]
+julia = "1.0"

src/MOF/MOF.jl

@@ -6,6 +6,10 @@ using DataStructures, JSON
 
 import ..MathOptFormat
 
+import ..MathOptFormat
+import JSONSchema
+const SCHEMA_PATH = joinpath(@__DIR__, "schema", "mof.schema.json")
+
 # we use an ordered dict to make the JSON printing nicer
 const Object = OrderedDict{String, Any}
 
@@ -52,6 +56,25 @@ function Base.show(io::IO, ::Model)
     return
 end
 
+"""
+    validate(filename::String)
+
+Validate that the MOF file `filename` conforms to the MOF JSON schema. Returns
+`nothing` if the file is valid, otherwise throws an error describing why the
+file is not valid.
+"""
+function validate(filename::String)
+    MathOptFormat.gzip_open(filename, "r") do io
+        object = JSON.parse(io)
+        mof_schema = JSONSchema.Schema(JSON.parsefile(SCHEMA_PATH))
+        if !JSONSchema.isvalid(object, mof_schema)
+            error("Unable to read file because it does not conform to the MOF " *
+                  "schema: ", JSONSchema.diagnose(object, mof_schema))
+        end
+    end
+    return
+end
+
 include("nonlinear.jl")
 
 include("read.jl")

src/MOF/schema/examples/biobjective.mof.json

@@ -0,0 +1,32 @@
+{
+    "description": "The problem: [min{2x - y + 1}, max{y}]",
+    "version": 0,
+    "variables": [{
+        "name": "x"
+    }, {
+        "name": "y"
+    }],
+    "objectives": [{
+        "sense": "min",
+        "function": {
+            "head": "ScalarAffineFunction",
+            "terms": [{
+                    "coefficient": 2,
+                    "variable": "x"
+                },
+                {
+                    "coefficient": -1,
+                    "variable": "y"
+                }
+            ],
+            "constant": 1
+        }
+    }, {
+        "sense": "max",
+        "function": {
+            "head": "SingleVariable",
+            "variable": "y"
+        }
+    }],
+    "constraints": []
+}

src/MOF/schema/examples/milp.mof.json

@@ -0,0 +1,58 @@
+{
+    "description": "The problem: min{x | x + y >= 1, x ∈ [0, 1], y ∈ {0, 1}}",
+    "version": 0,
+    "variables": [{
+        "name": "x",
+        "primal_start": 0.0
+    }, {
+        "name": "y",
+        "primal_start": 1.0
+    }],
+    "objectives": [{
+        "sense": "min",
+        "function": {
+            "head": "SingleVariable",
+            "variable": "x"
+        }
+    }],
+    "constraints": [{
+        "name": "x + y >= 1",
+        "function": {
+            "head": "ScalarAffineFunction",
+            "terms": [{
+                    "coefficient": 1,
+                    "variable": "x"
+                },
+                {
+                    "coefficient": 1,
+                    "variable": "y"
+                }
+            ],
+            "constant": 0
+        },
+        "set": {
+            "head": "GreaterThan",
+            "lower": 1
+        }
+    }, {
+        "name": "x ∈ [0, 1]",
+        "function": {
+            "head": "SingleVariable",
+            "variable": "x"
+        },
+        "set": {
+            "head": "Interval",
+            "lower": 0,
+            "upper": 1
+        }
+    }, {
+        "name": "y ∈ {0, 1}",
+        "function": {
+            "head": "SingleVariable",
+            "variable": "y"
+        },
+        "set": {
+            "head": "ZeroOne"
+        }
+    }]
+}

src/MOF/schema/examples/nlp.json

@@ -0,0 +1,57 @@
+{
+    "description": "The problem: min{2x + sin(x)^2 + y}.",
+    "version": 0,
+    "variables": [{
+        "name": "x"
+    }, {
+        "name": "y"
+    }],
+    "objectives": [{
+        "sense": "min",
+        "function": {
+            "head": "Nonlinear",
+            "root": {
+                "head": "node",
+                "index": 4
+            },
+            "node_list": [{
+                "head": "*",
+                "args": [{
+                    "head": "real",
+                    "value": 2
+                }, {
+                    "head": "variable",
+                    "name": "x"
+                }]
+            }, {
+                "head": "sin",
+                "args": [{
+                    "head": "variable",
+                    "name": "x"
+                }]
+            }, {
+                "head": "^",
+                "args": [{
+                    "head": "node",
+                    "index": 2
+                }, {
+                    "head": "real",
+                    "value": 2
+                }]
+            }, {
+                "head": "+",
+                "args": [{
+                    "head": "node",
+                    "index": 1
+                }, {
+                    "head": "node",
+                    "index": 3
+                }, {
+                    "head": "variable",
+                    "name": "y"
+                }]
+            }]
+        }
+    }],
+    "constraints": []
+}

src/MOF/schema/examples/quadratic.mof.json

@@ -0,0 +1,35 @@
+{
+    "description": "The problem: min{x^2 + x * y + y^2}",
+    "version": 0,
+    "variables": [{
+        "name": "x"
+    }, {
+        "name": "y"
+    }],
+    "objectives": [{
+        "sense": "min",
+        "function": {
+            "description": "Note that the format is `a'x + 0.5 x' Q x + c`.",
+            "head": "ScalarQuadraticFunction",
+            "affine_terms": [],
+            "quadratic_terms": [{
+                    "coefficient": 2,
+                    "variable_1": "x",
+                    "variable_2": "x"
+                },
+                {
+                    "coefficient": 1,
+                    "variable_1": "x",
+                    "variable_2": "y"
+                },
+                {
+                    "coefficient": 2,
+                    "variable_1": "y",
+                    "variable_2": "y"
+                }
+            ],
+            "constant": 0
+        }
+    }],
+    "constraints": []
+}

src/MOF/schema/examples/vector.json

@@ -0,0 +1,45 @@
+{
+    "description": "The problem: min{0 | [1 2; 3 4][x, y] + [5, 6] ∈ R+.",
+    "version": 0,
+    "variables": [{
+        "name": "x"
+    }, {
+        "name": "y"
+    }],
+    "objectives": [],
+    "constraints": [{
+        "function": {
+            "head": "VectorAffineFunction",
+            "terms": [{
+                "output_index": 1,
+                "scalar_term": {
+                    "coefficient": 1,
+                    "variable": "x"
+                }
+            }, {
+                "output_index": 1,
+                "scalar_term": {
+                    "coefficient": 2,
+                    "variable": "y"
+                }
+            }, {
+                "output_index": 2,
+                "scalar_term": {
+                    "coefficient": 3,
+                    "variable": "x"
+                }
+            }, {
+                "output_index": 2,
+                "scalar_term": {
+                    "coefficient": 4,
+                    "variable": "y"
+                }
+            }],
+            "constants": [5, 6]
+        },
+        "set": {
+            "head": "Nonnegatives",
+            "dimension": 2
+        }
+    }]
+}