--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SilverlightGlimpse/SilverFlow.Controls/Extensions/MathExtensions.cs	Sun Apr 22 13:33:42 2012 +0100
@@ -0,0 +1,85 @@
+using System;
+
+namespace SilverFlow.Controls.Extensions
+{
+    /// <summary>
+    /// Math extensions
+    /// </summary>
+    public static class MathExtensions
+    {
+        /// <summary>
+        /// Determines whether the number is NaN.
+        /// </summary>
+        /// <param name="number">The number.</param>
+        /// <returns>
+        /// <c>true</c> if is NaN; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool IsNotSet(this double number)
+        {
+            return double.IsNaN(number);
+        }
+
+        /// <summary>
+        /// Determines whether the specified number is near the test number.
+        /// </summary>
+        /// <param name="number">The number.</param>
+        /// <param name="testNumber">The test number.</param>
+        /// <param name="accuracy">Accuracy.</param>
+        /// <returns>
+        /// <c>true</c> if the specified number is near the testing one; otherwise, <c>false</c>.
+        /// </returns>
+        public static bool IsNear(this double number, double testNumber, double accuracy)
+        {
+            return number >= (testNumber - accuracy) && number <= (testNumber + accuracy);
+        }
+
+        /// <summary>
+        /// Compares two numbers without their signs and gets absolutely minimal value.
+        /// </summary>
+        /// <param name="num1">First number.</param>
+        /// <param name="num2">Second number.</param>
+        /// <returns>Absolutely minimal value.</returns>
+        public static double AbsMin(double num1, double num2)
+        {
+            if (num1.IsNotSet() && num2.IsNotSet())
+                return double.NaN;
+
+            if (num1.IsNotSet()) return num2;
+            if (num2.IsNotSet()) return num1;
+
+            double abs1 = Math.Abs(num1);
+            double abs2 = Math.Abs(num2);
+
+            if (abs1 < abs2) return num1;
+            if (abs2 < abs1) return num2;
+
+            // Abs. values are equal. Return first number
+            return num1;
+        }
+
+        /// <summary>
+        /// Ensures the given number is in the specified range.
+        /// </summary>
+        /// <param name="number">The number.</param>
+        /// <param name="low">The lower limit.</param>
+        /// <param name="high">The upper limit.</param>
+        /// <returns>A number in the specified range.</returns>
+        public static double EnsureInRange(this double number, double low, double high)
+        {
+            if (number.IsNotSet()) return double.NaN;
+
+            double result = Math.Max(number, low);
+            return Math.Min(result, high);
+        }
+
+        /// <summary>
+        /// Returns a double value if it is not a NAN, or zero.
+        /// </summary>
+        /// <param name="number">The number.</param>
+        /// <returns>Double value if it is not a NAN, or zero.</returns>
+        public static double ValueOrZero(this double number)
+        {
+            return double.IsNaN(number) ? 0 : number;
+        }
+    }
+}