Optimization: tweak IObjectiveFunction interface

src/Numerics/Optimization/BaseObjectiveFunction.cs

@@ -11,14 +11,14 @@ namespace MathNet.Numerics.Optimization
         protected Vector<double> GradientRaw { get; set; }
         protected Matrix<double> HessianRaw { get; set; }
 
-        public bool GradientSupported { get; private set; }
-        public bool HessianSupported { get; private set; }
+        public bool IsGradientSupported { get; private set; }
+        public bool IsHessianSupported { get; private set; }
 
         protected BaseObjectiveFunction(bool gradientSupported, bool hessianSupported)
         {
             Status = EvaluationStatus.None;
-            GradientSupported = gradientSupported;
-            HessianSupported = hessianSupported;
+            IsGradientSupported = gradientSupported;
+            IsHessianSupported = hessianSupported;
         }
 
         public Vector<double> Point
@@ -34,6 +34,12 @@ namespace MathNet.Numerics.Optimization
             }
         }
 
+        public void EvaluateAt(Vector<double> point)
+        {
+            PointRaw = point;
+            Status = EvaluationStatus.None;
+        }
+
         public double Value
         {
             get
@@ -71,9 +77,10 @@ namespace MathNet.Numerics.Optimization
             }
         }
 
+        public abstract IObjectiveFunction Fork();
+
         protected abstract void SetValue();
         protected abstract void SetGradient();
         protected abstract void SetHessian();
-        public abstract IObjectiveFunction CreateNew();
     }
 }

src/Numerics/Optimization/IObjectiveFunction.cs

@@ -4,18 +4,26 @@ using MathNet.Numerics.LinearAlgebra;
 namespace MathNet.Numerics.Optimization
 {
     [Flags]
-    public enum EvaluationStatus { None = 0, Value = 1, Gradient = 2, Hessian = 4 }
+    public enum EvaluationStatus
+    {
+        None = 0,
+        Value = 1,
+        Gradient = 2,
+        Hessian = 4
+    }
 
     public interface IObjectiveFunction
     {
-        Vector<double> Point { get; set; }
-        IObjectiveFunction CreateNew();
+        void EvaluateAt(Vector<double> point);
+        IObjectiveFunction Fork();
 
-        // Used by algorithm
-        bool GradientSupported { get; }
-        bool HessianSupported { get; }
+        Vector<double> Point { get; }
         double Value { get; }
+
+        bool IsGradientSupported { get; }
         Vector<double> Gradient { get; }
+
+        bool IsHessianSupported { get; }
         Matrix<double> Hessian { get; }
     }
 }

src/Numerics/Optimization/Implementation/CheckedObjectiveFunction.cs

@@ -25,7 +25,11 @@ namespace MathNet.Numerics.Optimization.Implementation
         public Vector<double> Point
         {
             get { return InnerObjectiveFunction.Point; }
-            set { InnerObjectiveFunction.Point = value; }
+        }
+
+        public void EvaluateAt(Vector<double> point)
+        {
+            InnerObjectiveFunction.EvaluateAt(point);
         }
 
         public double Value
@@ -97,19 +101,19 @@ namespace MathNet.Numerics.Optimization.Implementation
             }
         }
 
-        public IObjectiveFunction CreateNew()
+        public IObjectiveFunction Fork()
         {
             return new CheckedObjectiveFunction(InnerObjectiveFunction, ValueChecker, GradientChecker, HessianChecker);
         }
 
-        public bool GradientSupported
+        public bool IsGradientSupported
         {
-            get { return InnerObjectiveFunction.GradientSupported; }
+            get { return InnerObjectiveFunction.IsGradientSupported; }
         }
 
-        public bool HessianSupported
+        public bool IsHessianSupported
         {
-            get { return InnerObjectiveFunction.HessianSupported; }
+            get { return InnerObjectiveFunction.IsHessianSupported; }
         }
     }
 }

src/Numerics/Optimization/Implementation/NullObjectiveFunction.cs

@@ -10,6 +10,7 @@ namespace MathNet.Numerics.Optimization.Implementation
         {
             Point = point;
         }
+
         protected override void SetValue()
         {
             throw new NotImplementedException();
@@ -25,7 +26,7 @@ namespace MathNet.Numerics.Optimization.Implementation
             throw new NotImplementedException();
         }
 
-        public override IObjectiveFunction CreateNew()
+        public override IObjectiveFunction Fork()
         {
             throw new NotImplementedException();
         }

src/Numerics/Optimization/Implementation/WeakWolfeLineSearch.cs

@@ -36,11 +36,11 @@ namespace MathNet.Numerics.Optimization.Implementation
             double initialDd = searchDirection * initialGradient;
 
             int ii;
-            IObjectiveFunction candidateEval = objective.CreateNew();
+            IObjectiveFunction candidateEval = objective.Fork();
             MinimizationOutput.ExitCondition reasonForExit = MinimizationOutput.ExitCondition.None;
             for (ii = 0; ii < _maximumIterations; ++ii)
             {
-                candidateEval.Point = startingPoint.Point + searchDirection * step;
+                candidateEval.EvaluateAt(startingPoint.Point + searchDirection * step);
 
                 double stepDd = searchDirection * candidateEval.Gradient;
 

src/Numerics/Optimization/NewtonMinimizer.cs

@@ -20,17 +20,17 @@ namespace MathNet.Numerics.Optimization
 
         public MinimizationOutput FindMinimum(IObjectiveFunction objective, Vector<double> initialGuess)
         {
-            if (!objective.GradientSupported)
+            if (!objective.IsGradientSupported)
                 throw new IncompatibleObjectiveException("Gradient not supported in objective function, but required for Newton minimization.");
 
-            if (!objective.HessianSupported)
+            if (!objective.IsHessianSupported)
                 throw new IncompatibleObjectiveException("Hessian not supported in objective function, but required for Newton minimization.");
 
             if (!(objective is CheckedObjectiveFunction))
                 objective = new CheckedObjectiveFunction(objective, ValidateObjective, ValidateGradient, ValidateHessian);
 
-            IObjectiveFunction initialEval = objective.CreateNew();
-            initialEval.Point = initialGuess;
+            IObjectiveFunction initialEval = objective.Fork();
+            initialEval.EvaluateAt(initialGuess);
 
             // Check that we're not already done
             if (ExitCriteriaSatisfied(initialGuess, initialEval.Gradient))
@@ -73,7 +73,7 @@ namespace MathNet.Numerics.Optimization
                 }
                 else
                 {
-                    candidatePoint.Point = candidatePoint.Point + searchDirection;
+                    candidatePoint.EvaluateAt(candidatePoint.Point + searchDirection);
                 }
 
                 tmpLineSearch = false;

src/UnitTests/OptimizationTests/TestNewtonMinimizer.cs

@@ -25,7 +25,7 @@ namespace MathNet.Numerics.UnitTests.OptimizationTests
             HessianRaw = RosenbrockFunction.Hessian(Point);
         }
 
-        public override IObjectiveFunction CreateNew()
+        public override IObjectiveFunction Fork()
         {
             return new RosenbrockObjectiveFunction();
         }