Optimization: (Lazy)ObjectiveFunction base classes

src/Numerics/Numerics.csproj

@@ -102,9 +102,9 @@
     <Compile Include="LinearAlgebra\Solvers\DelegateStopCriterion.cs" />
     <Compile Include="LinearAlgebra\CreateVector.cs" />
     <Compile Include="LinearRegression\Options.cs" />
-    <Compile Include="Optimization\BaseObjectiveFunction.cs" />
+    <Compile Include="Optimization\ObjectiveFunctions\LazyObjectiveFunctionBase.cs" />
     <Compile Include="Optimization\Exceptions.cs" />
-    <Compile Include="Optimization\ObjectiveFunctions\InplaceObjectiveFunction.cs" />
+    <Compile Include="Optimization\ObjectiveFunctions\ObjectiveFunctionBase.cs" />
     <Compile Include="Optimization\ObjectiveFunctions\LazyObjectiveFunction.cs" />
     <Compile Include="Optimization\ObjectiveFunction.cs" />
     <Compile Include="Optimization\ObjectiveFunctions\ValueObjectiveFunction.cs" />

src/Numerics/Optimization/BaseObjectiveFunction.cs

@@ -1,99 +0,0 @@
-using System;
-using MathNet.Numerics.LinearAlgebra;
-
-namespace MathNet.Numerics.Optimization
-{
-    public abstract class BaseObjectiveFunction : IObjectiveFunction
-    {
-        [Flags]
-        enum EvaluationStatus
-        {
-            None = 0,
-            Value = 1,
-            Gradient = 2,
-            Hessian = 4
-        }
-
-        EvaluationStatus Status { get; set; }
-
-        protected Vector<double> PointRaw { get; set; }
-        protected double ValueRaw { get; set; }
-        protected Vector<double> GradientRaw { get; set; }
-        protected Matrix<double> HessianRaw { get; set; }
-
-        public bool IsGradientSupported { get; private set; }
-        public bool IsHessianSupported { get; private set; }
-
-        protected BaseObjectiveFunction(bool gradientSupported, bool hessianSupported)
-        {
-            Status = EvaluationStatus.None;
-            IsGradientSupported = gradientSupported;
-            IsHessianSupported = hessianSupported;
-        }
-
-        public Vector<double> Point
-        {
-            get { return PointRaw; }
-        }
-
-        public void EvaluateAt(Vector<double> point)
-        {
-            PointRaw = point;
-            Status = EvaluationStatus.None;
-        }
-
-        public double Value
-        {
-            get
-            {
-                if (!Status.HasFlag(EvaluationStatus.Value))
-                {
-                    SetValue();
-                    Status |= EvaluationStatus.Value;
-                }
-                return ValueRaw;
-            }
-        }
-        public Vector<double> Gradient
-        {
-            get
-            {
-                if (!Status.HasFlag(EvaluationStatus.Gradient))
-                {
-                    SetGradient();
-                    Status |= EvaluationStatus.Gradient;
-                }
-                return GradientRaw;
-            }
-        }
-        public Matrix<double> Hessian
-        {
-            get
-            {
-                if (!Status.HasFlag(EvaluationStatus.Hessian))
-                {
-                    SetHessian();
-                    Status |= EvaluationStatus.Hessian;
-                }
-                return HessianRaw;
-            }
-        }
-
-        public abstract IObjectiveFunction CreateNew();
-
-        public virtual IObjectiveFunction Fork()
-        {
-            BaseObjectiveFunction fork = (BaseObjectiveFunction)CreateNew();
-            fork.PointRaw = PointRaw;
-            fork.ValueRaw = ValueRaw;
-            fork.GradientRaw = GradientRaw;
-            fork.HessianRaw = HessianRaw;
-            fork.Status = Status;
-            return fork;
-        }
-
-        protected abstract void SetValue();
-        protected abstract void SetGradient();
-        protected abstract void SetHessian();
-    }
-}

src/Numerics/Optimization/ObjectiveFunctions/InplaceObjectiveFunction.cs

@@ -1,62 +0,0 @@
-using MathNet.Numerics.LinearAlgebra;
-
-namespace MathNet.Numerics.Optimization.ObjectiveFunctions
-{
-    public abstract class InplaceObjectiveFunction : IObjectiveFunction
-    {
-        Vector<double> _point;
-        double _functionValue;
-        Vector<double> _gradientValue;
-        Matrix<double> _hessianValue;
-
-        protected InplaceObjectiveFunction(bool isGradientSupported, bool isHessianSupported)
-        {
-            IsGradientSupported = isGradientSupported;
-            IsHessianSupported = isHessianSupported;
-        }
-
-        public abstract IObjectiveFunction CreateNew();
-
-        public virtual IObjectiveFunction Fork()
-        {
-            // no need to deep-clone values since they are replaced on evaluation
-            InplaceObjectiveFunction objective = (InplaceObjectiveFunction)CreateNew();
-            objective._point = _point == null ? null : _point.Clone();
-            objective._functionValue = _functionValue;
-            objective._gradientValue = _gradientValue == null ? null : _gradientValue.Clone();
-            objective._hessianValue = _hessianValue == null ? null : _hessianValue.Clone();
-            return objective;
-        }
-
-        public bool IsGradientSupported { get; private set; }
-        public bool IsHessianSupported { get; private set; }
-
-        public void EvaluateAt(Vector<double> point)
-        {
-            _point = point;
-            EvaluateAt(_point, ref _functionValue, ref _gradientValue, ref _hessianValue);
-        }
-
-        protected abstract void EvaluateAt(Vector<double> point, ref double value, ref Vector<double> gradient, ref Matrix<double> hessian);
-
-        public Vector<double> Point
-        {
-            get { return _point; }
-        }
-
-        public double Value
-        {
-            get { return _functionValue; }
-        }
-
-        public Vector<double> Gradient
-        {
-            get { return _gradientValue; }
-        }
-
-        public Matrix<double> Hessian
-        {
-            get { return _hessianValue; }
-        }
-    }
-}

src/Numerics/Optimization/ObjectiveFunctions/LazyObjectiveFunctionBase.cs

@@ -0,0 +1,119 @@
+using MathNet.Numerics.LinearAlgebra;
+
+namespace MathNet.Numerics.Optimization.ObjectiveFunctions
+{
+    public abstract class LazyObjectiveFunctionBase : IObjectiveFunction
+    {
+        Vector<double> _point;
+
+        bool _hasFunctionValue;
+        double _functionValue;
+
+        bool _hasGradientValue;
+        Vector<double> _gradientValue;
+
+        bool _hasHessianValue;
+        Matrix<double> _hessianValue;
+
+        protected LazyObjectiveFunctionBase(bool gradientSupported, bool hessianSupported)
+        {
+            IsGradientSupported = gradientSupported;
+            IsHessianSupported = hessianSupported;
+        }
+
+        public abstract IObjectiveFunction CreateNew();
+
+        public virtual IObjectiveFunction Fork()
+        {
+            // we need to deep-clone values since they may be updated inplace on evaluation
+            LazyObjectiveFunctionBase fork = (LazyObjectiveFunctionBase)CreateNew();
+            fork._point = _point == null ? null : _point.Clone();
+            fork._hasFunctionValue = _hasFunctionValue;
+            fork._functionValue = _functionValue;
+            fork._hasGradientValue = _hasGradientValue;
+            fork._gradientValue = _gradientValue == null ? null : _gradientValue.Clone(); ;
+            fork._hasHessianValue = _hasHessianValue;
+            fork._hessianValue = _hessianValue == null ? null : _hessianValue.Clone();
+            return fork;
+        }
+
+        public bool IsGradientSupported { get; private set; }
+        public bool IsHessianSupported { get; private set; }
+
+        public void EvaluateAt(Vector<double> point)
+        {
+            _point = point;
+            _hasFunctionValue = false;
+            _hasGradientValue = false;
+            _hasHessianValue = false;
+        }
+
+        protected abstract void EvaluateValue();
+
+        protected virtual void EvaluateGradient()
+        {
+            Gradient = null;
+        }
+
+        protected virtual void EvaluateHessian()
+        {
+            Hessian = null;
+        }
+
+        public Vector<double> Point
+        {
+            get { return _point; }
+        }
+
+        public double Value
+        {
+            get
+            {
+                if (!_hasFunctionValue)
+                {
+                    EvaluateValue();
+                }
+                return _functionValue;
+            }
+            protected set
+            {
+                _functionValue = value;
+                _hasFunctionValue = true;
+            }
+        }
+
+        public Vector<double> Gradient
+        {
+            get
+            {
+                if (!_hasGradientValue)
+                {
+                    EvaluateGradient();
+                }
+                return _gradientValue;
+            }
+            protected set
+            {
+                _gradientValue = value;
+                _hasGradientValue = true;
+            }
+        }
+
+        public Matrix<double> Hessian
+        {
+            get
+            {
+                if (!_hasHessianValue)
+                {
+                    EvaluateHessian();
+                }
+                return _hessianValue;
+            }
+            protected set
+            {
+                _hessianValue = value;
+                _hasHessianValue = true;
+            }
+        }
+    }
+}

src/Numerics/Optimization/ObjectiveFunctions/ObjectiveFunctionBase.cs

@@ -0,0 +1,42 @@
+using MathNet.Numerics.LinearAlgebra;
+
+namespace MathNet.Numerics.Optimization.ObjectiveFunctions
+{
+    public abstract class ObjectiveFunctionBase : IObjectiveFunction
+    {
+        protected ObjectiveFunctionBase(bool isGradientSupported, bool isHessianSupported)
+        {
+            IsGradientSupported = isGradientSupported;
+            IsHessianSupported = isHessianSupported;
+        }
+
+        public abstract IObjectiveFunction CreateNew();
+
+        public virtual IObjectiveFunction Fork()
+        {
+            // we need to deep-clone values since they may be updated inplace on evaluation
+            ObjectiveFunctionBase objective = (ObjectiveFunctionBase)CreateNew();
+            objective.Point = Point == null ? null : Point.Clone();
+            objective.Value = Value;
+            objective.Gradient = Gradient == null ? null : Gradient.Clone();
+            objective.Hessian = Hessian == null ? null : Hessian.Clone();
+            return objective;
+        }
+
+        public bool IsGradientSupported { get; private set; }
+        public bool IsHessianSupported { get; private set; }
+
+        public void EvaluateAt(Vector<double> point)
+        {
+            Point = point;
+            Evaluate();
+        }
+
+        protected abstract void Evaluate();
+
+        public Vector<double> Point { get; private set; }
+        public double Value { get; protected set; }
+        public Vector<double> Gradient { get; protected set; }
+        public Matrix<double> Hessian { get; protected set; }
+    }
+}

src/UnitTests/OptimizationTests/TestNewtonMinimizer.cs

@@ -1,5 +1,4 @@
 using System;
-using MathNet.Numerics.LinearAlgebra;
 using MathNet.Numerics.LinearAlgebra.Double;
 using MathNet.Numerics.Optimization;
 using MathNet.Numerics.Optimization.ObjectiveFunctions;
@@ -7,47 +6,47 @@ using NUnit.Framework;
 
 namespace MathNet.Numerics.UnitTests.OptimizationTests
 {
-    public class RosenbrockObjectiveFunction : BaseObjectiveFunction
+    public class LazyRosenbrockObjectiveFunction : LazyObjectiveFunctionBase
     {
-        public RosenbrockObjectiveFunction() : base(true, true) { }
+        public LazyRosenbrockObjectiveFunction() : base(true, true) { }
 
-        protected override void SetValue()
+        public override IObjectiveFunction CreateNew()
         {
-            ValueRaw = RosenbrockFunction.Value(Point);
+            return new LazyRosenbrockObjectiveFunction();
         }
 
-        protected override void SetGradient()
+        protected override void EvaluateValue()
         {
-            GradientRaw = RosenbrockFunction.Gradient(Point);
+            Value = RosenbrockFunction.Value(Point);
         }
 
-        protected override void SetHessian()
+        protected override void EvaluateGradient()
         {
-            HessianRaw = RosenbrockFunction.Hessian(Point);
+            Gradient = RosenbrockFunction.Gradient(Point);
         }
 
-        public override IObjectiveFunction CreateNew()
+        protected override void EvaluateHessian()
         {
-            return new RosenbrockObjectiveFunction();
+            Hessian = RosenbrockFunction.Hessian(Point);
         }
     }
 
-    public class InplaceRosenbrockObjectiveFunction : InplaceObjectiveFunction
+    public class RosenbrockObjectiveFunction : ObjectiveFunctionBase
     {
-        public InplaceRosenbrockObjectiveFunction() : base(true, true) { }
+        public RosenbrockObjectiveFunction() : base(true, true) { }
 
         public override IObjectiveFunction CreateNew()
         {
-            return new InplaceRosenbrockObjectiveFunction();
+            return new RosenbrockObjectiveFunction();
         }
 
-        protected override void EvaluateAt(Vector<double> point, ref double value, ref Vector<double> gradient, ref Matrix<double> hessian)
+        protected override void Evaluate()
         {
-            // here we could directly overwrite the existing matrices instead.
+            // here we could directly overwrite the existing matrix cells instead.
-            // note: values must then be initialized manually here first, if null.
+            // note: values must then be initialized manually first, if null.
-            value = RosenbrockFunction.Value(point);
+            Value = RosenbrockFunction.Value(Point);
-            gradient = RosenbrockFunction.Gradient(point);
+            Gradient = RosenbrockFunction.Gradient(Point);
-            hessian = RosenbrockFunction.Hessian(point);
+            Hessian = RosenbrockFunction.Hessian(Point);
         }
     }
 
@@ -79,7 +78,7 @@ namespace MathNet.Numerics.UnitTests.OptimizationTests
         [Test]
         public void FindMinimum_Rosenbrock_Overton()
         {
-            var obj = new RosenbrockObjectiveFunction();
+            var obj = new LazyRosenbrockObjectiveFunction();
             var solver = new NewtonMinimizer(1e-5, 1000);
             var result = solver.FindMinimum(obj, new DenseVector(new[] { -0.9, -0.5 }));
 
@@ -90,7 +89,7 @@ namespace MathNet.Numerics.UnitTests.OptimizationTests
         [Test]
         public void FindMinimum_Linesearch_Rosenbrock_Easy()
         {
-            var obj = new InplaceRosenbrockObjectiveFunction();
+            var obj = new RosenbrockObjectiveFunction();
             var solver = new NewtonMinimizer(1e-5, 1000, true);
             var result = solver.FindMinimum(obj, new DenseVector(new[] { 1.2, 1.2 }));
 
@@ -101,7 +100,7 @@ namespace MathNet.Numerics.UnitTests.OptimizationTests
         [Test]
         public void FindMinimum_Linesearch_Rosenbrock_Hard()
         {
-            var obj = new RosenbrockObjectiveFunction();
+            var obj = new LazyRosenbrockObjectiveFunction();
             var solver = new NewtonMinimizer(1e-5, 1000, true);
             var result = solver.FindMinimum(obj, new DenseVector(new[] { -1.2, 1.0 }));
 
@@ -112,7 +111,7 @@ namespace MathNet.Numerics.UnitTests.OptimizationTests
         [Test]
         public void FindMinimum_Linesearch_Rosenbrock_Overton()
         {
-            var obj = new RosenbrockObjectiveFunction();
+            var obj = new LazyRosenbrockObjectiveFunction();
             var solver = new NewtonMinimizer(1e-5, 1000, true);
             var result = solver.FindMinimum(obj, new DenseVector(new[] { -0.9, -0.5 }));