quadrature: some methods are now static

Signed-off-by: Christoph Ruegg <git@cdrnet.ch>

src/Managed.UnitTests/IntegrationTests/IntegrationTest.cs

@@ -82,11 +82,9 @@ namespace MathNet.Numerics.UnitTests.IntegrationTests
         [Test]
         public void TrapeziumRuleSupportsTwoPointIntegration()
         {
-            var algorithm = new NewtonCotesTrapeziumRule();
-
             Assert.AreApproximatelyEqual(
                 TargetAreaA,
-                algorithm.IntegrateTwoPoint(TargetFunctionA, StartA, StopA),
+                NewtonCotesTrapeziumRule.IntegrateTwoPoint(TargetFunctionA, StartA, StopA),
                 0.4 * TargetAreaA,
                 "Direct (1 Partition)");
         }
@@ -99,11 +97,9 @@ namespace MathNet.Numerics.UnitTests.IntegrationTests
         [Row(1000, 1.5e-6)]
         public void TrapeziumRuleSupportsCompositeIntegration(int partitions, double maxRelativeError)
         {
-            var algorithm = new NewtonCotesTrapeziumRule();
-
             Assert.AreApproximatelyEqual(
                 TargetAreaA,
-                algorithm.IntegrateComposite(TargetFunctionA, StartA, StopA, partitions),
+                NewtonCotesTrapeziumRule.IntegrateComposite(TargetFunctionA, StartA, StopA, partitions),
                 maxRelativeError * TargetAreaA,
                 "Composite {0} Partitions", partitions);
         }
@@ -114,11 +110,9 @@ namespace MathNet.Numerics.UnitTests.IntegrationTests
         [Row(1e-10)]
         public void TrapeziumRuleSupportsAdaptiveIntegration(double targetRelativeError)
         {
-            var algorithm = new NewtonCotesTrapeziumRule();
-
             Assert.AreApproximatelyEqual(
                 TargetAreaA,
-                algorithm.IntegrateAdaptive(TargetFunctionA, StartA, StopA, targetRelativeError),
+                NewtonCotesTrapeziumRule.IntegrateAdaptive(TargetFunctionA, StartA, StopA, targetRelativeError),
                 targetRelativeError * TargetAreaA,
                 "Adaptive {0}", targetRelativeError);
         }
@@ -126,11 +120,9 @@ namespace MathNet.Numerics.UnitTests.IntegrationTests
         [Test]
         public void SimpsonRuleSupportsThreePointIntegration()
         {
-            var algorithm = new SimpsonRule();
-
             Assert.AreApproximatelyEqual(
                 TargetAreaA,
-                algorithm.IntegrateThreePoint(TargetFunctionA, StartA, StopA),
+                SimpsonRule.IntegrateThreePoint(TargetFunctionA, StartA, StopA),
                 0.2 * TargetAreaA,
                 "Direct (2 Partitions)");
         }
@@ -143,11 +135,9 @@ namespace MathNet.Numerics.UnitTests.IntegrationTests
         [Row(1000, 5e-11)]
         public void SimpsonRuleSupportsCompositeIntegration(int partitions, double maxRelativeError)
         {
-            var algorithm = new SimpsonRule();
-
             Assert.AreApproximatelyEqual(
                 TargetAreaA,
-                algorithm.IntegrateComposite(TargetFunctionA, StartA, StopA, partitions),
+                SimpsonRule.IntegrateComposite(TargetFunctionA, StartA, StopA, partitions),
                 maxRelativeError * TargetAreaA,
                 "Composite {0} Partitions", partitions);
         }

src/Managed/Integration/Algorithms/DoubleExponentialTransformation.cs

@@ -491,11 +491,6 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// </summary>
         private const int NumberOfMaximumLevels = 10;
 
-        /// <summary>
-        /// Internal Trapezium Rule.
-        /// </summary>
-        private readonly NewtonCotesTrapeziumRule _trapezium = new NewtonCotesTrapeziumRule();
-
         /// <summary>
         /// Abscissa vector per level provider.
         /// </summary>
@@ -526,7 +521,7 @@ namespace MathNet.Numerics.Integration.Algorithms
                 _levelWeights = ProvideLevelWeights();
             }
 
-            return _trapezium.IntegrateAdaptiveTransformedOdd(
+            return NewtonCotesTrapeziumRule.IntegrateAdaptiveTransformedOdd(
                 f,
                 intervalBegin,
                 intervalEnd,

src/Managed/Integration/Algorithms/NewtonCotesTrapeziumRule.cs

@@ -38,7 +38,7 @@ namespace MathNet.Numerics.Integration.Algorithms
     /// <remarks>
     /// <a href="http://en.wikipedia.org/wiki/Trapezium_rule">Wikipedia - Trapezium Rule</a>
     /// </remarks>
-    public class NewtonCotesTrapeziumRule
+    public static class NewtonCotesTrapeziumRule
     {
         /// <summary>
         /// Direct 2-point approximation of the definite integral in the provided interval by the trapezium rule.
@@ -47,7 +47,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="intervalBegin">Where the interval starts, inclusive and finite.</param>
         /// <param name="intervalEnd">Where the interval stops, inclusive and finite.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateTwoPoint(
+        public static double IntegrateTwoPoint(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd)
@@ -63,7 +63,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="intervalEnd">Where the interval stops, inclusive and finite.</param>
         /// <param name="numberOfPartitions">Number of composite subdivision partitions.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateComposite(
+        public static double IntegrateComposite(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd,
@@ -96,7 +96,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="intervalEnd">Where the interval stops, inclusive and finite.</param>
         /// <param name="targetRelativeError">The expected relative accuracy of the approximation.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateAdaptive(
+        public static double IntegrateAdaptive(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd,
@@ -138,7 +138,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="levelOneStep">First Level Step</param>
         /// <param name="targetRelativeError">The expected relative accuracy of the approximation.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateAdaptiveTransformedOdd(
+        public static double IntegrateAdaptiveTransformedOdd(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd,

src/Managed/Integration/Algorithms/SimpsonRule.cs

@@ -35,7 +35,7 @@ namespace MathNet.Numerics.Integration.Algorithms
     /// <summary>
     /// Approximation algorithm for definite integrals by Simpson's rule.
     /// </summary>
-    public class SimpsonRule
+    public static class SimpsonRule
     {
         /// <summary>
         /// Direct 3-point approximation of the definite integral in the provided interval by Simpson's rule.
@@ -44,7 +44,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="intervalBegin">Where the interval starts, inclusive and finite.</param>
         /// <param name="intervalEnd">Where the interval stops, inclusive and finite.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateThreePoint(
+        public static double IntegrateThreePoint(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd)
@@ -61,7 +61,7 @@ namespace MathNet.Numerics.Integration.Algorithms
         /// <param name="intervalEnd">Where the interval stops, inclusive and finite.</param>
         /// <param name="numberOfPartitions">Even number of composite subdivision partitions.</param>
         /// <returns>Approximation of the finite integral in the given interval.</returns>
-        public double IntegrateComposite(
+        public static double IntegrateComposite(
             Func<double, double> f,
             double intervalBegin,
             double intervalEnd,