There are many Math Extension Classes out there for the Netduino. No Need to reinvent the wheel. Here is one I use.
public static class MathEX { #region Internaly used constants const double sq2p1 = 2.414213562373095048802e0F; const double sq2m1 = .414213562373095048802e0F; const double pio2 = 1.570796326794896619231e0F; const double pio4 = .785398163397448309615e0F; const double log2e = 1.4426950408889634073599247F; const double sqrt2 = 1.4142135623730950488016887F; const double ln2 = 6.93147180559945286227e-01F; const double atan_p4 = .161536412982230228262e2F; const double atan_p3 = .26842548195503973794141e3F; const double atan_p2 = .11530293515404850115428136e4F; const double atan_p1 = .178040631643319697105464587e4F; const double atan_p0 = .89678597403663861959987488e3F; const double atan_q4 = .5895697050844462222791e2F; const double atan_q3 = .536265374031215315104235e3F; const double atan_q2 = .16667838148816337184521798e4F; const double atan_q1 = .207933497444540981287275926e4F; const double atan_q0 = .89678597403663861962481162e3F; #endregion /// <summary> /// PI /// </summary> public static readonly double PI = 3.14159265358979323846F; /// <summary> /// Natural base E /// </summary> public static readonly double E = 2.71828182845904523536F; /// <summary> /// Returns the absolute value /// </summary> /// <param name="x">A number</param> /// <returns>absolute value of x</returns> public static double Abs(double x) { if (x >= 0.0F) return x; else return (-x); } /// <summary> /// Returns the angle whose cosine is the specified number /// </summary> /// <param name="x">A number representing a cosine</param> /// <returns>An angle</returns> public static double Acos(double x) { if ((x > 1.0F) || (x < -1.0F)) throw new System.ArgumentOutOfRangeException("Domain error"); return (pio2 - Asin(x)); } /// <summary> /// Returns the angle whose sine is the specified number /// </summary> /// <param name="x">A number representing a sine</param> /// <returns>An angle</returns> public static double Asin(double x) { double sign, temp; sign = 1.0F; if (x < 0.0F) { x = -x; sign = -1.0F; } if (x > 1.0F) { throw new System.ArgumentOutOfRangeException("Domain error"); } temp = Sqrt(1.0F - (x * x)); if (x > 0.7) { temp = pio2 - Atan(temp / x); } else { temp = Atan(x / temp); } return (sign * temp); } /// <summary> /// Returns the angle whose tangent is the specified number /// </summary> /// <param name="x">A number representing a tangent</param> /// <returns>the arctangent of x</returns> public static double Atan(double x) { if (x > 0.0F) return (atans(x)); else return (-atans(-x)); } /// <summary> /// Returns the angle whose tangent is the quotient of two specified numbers. /// </summary> /// <param name="y">The y coordinate of a point</param> /// <param name="x">The x coordinate of a point</param> /// <returns>the arctangent of x/y</returns> public static double Atan2(double y, double x) { if ((x + y) == x) { if ((x == 0F) & (y == 0F)) return 0F; if (x >= 0.0F) return pio2; else return (-pio2); } else if (y < 0.0F) { if (x >= 0.0F) return ((pio2 * 2) - atans((-x) / y)); else return (((-pio2) * 2) + atans(x / y)); } else if (x > 0.0F) { return (atans(x / y)); } else { return (-atans((-x) / y)); } } /// <summary> /// Returns the smallest integer greater than or equal to the specified number /// </summary> /// <param name="x">a Number</param> /// <returns>the smallest integer greater than or equal to x</returns> public static double Ceiling(double x) { return System.Math.Ceiling(x); } /// <summary> /// Calculate Cosinus /// </summary> /// <param name="x">Value</param> /// <returns>Cosinus of Value</returns> public static double Cos(double x) { // This function is based on the work described in // http://www.ganssle.com/approx/approx.pdf // Make X positive if negative if (x < 0) { x = 0.0F - x; } // Get quadrand // Quadrand 0, >-- Pi/2 byte quadrand = 0; // Quadrand 1, Pi/2 -- Pi if ((x > (System.Math.PI / 2F)) & (x < (System.Math.PI))) { quadrand = 1; x = System.Math.PI - x; } // Quadrand 2, Pi -- 3Pi/2 if ((x > (System.Math.PI)) & (x < ((3F * System.Math.PI) / 2))) { quadrand = 2; x = System.Math.PI - x; } // Quadrand 3 - 3Pi/2 --> if ((x > ((3F * System.Math.PI) / 2))) { quadrand = 3; x = (2F * System.Math.PI) - x; } // Constants used for approximation const double c1 = 0.99999999999925182; const double c2 = -0.49999999997024012; const double c3 = 0.041666666473384543; const double c4 = -0.001388888418000423; const double c5 = 0.0000248010406484558; const double c6 = -0.0000002752469638432; const double c7 = 0.0000000019907856854; // X squared double x2 = x * x; ; // Check quadrand if ((quadrand == 0) | (quadrand == 3)) { // Return positive for quadrand 0, 3 return (c1 + x2 * (c2 + x2 * (c3 + x2 * (c4 + x2 * (c5 + x2 * (c6 + c7 * x2)))))); } else { // Return negative for quadrand 1, 2 return 0.0F - (c1 + x2 * (c2 + x2 * (c3 + x2 * (c4 + x2 * (c5 + x2 * (c6 + c7 * x2)))))); } } /// <summary> /// Returns the hyperbolic cosine of the specified angle /// </summary> /// <param name="x">An angle, measured in radians</param> /// <returns>hyperbolic cosine of x</returns> public static double Cosh(double x) { if (x < 0.0F) x = -x; if (x == 0F) { return 1F; } else if (x <= (ln2 / 2)) { return (1 + (_power((Exp(x) - 1), 2) / (2 * Exp(x)))); } else if (x <= 22F) { return ((Exp(x) + (1 / Exp(x))) / 2); } else { return (0.5F * (Exp(x) + Exp(-x))); } } /// <summary> /// Returns e raised to the specified power /// </summary> /// <param name="x">A number specifying a power</param> /// <returns>e raised to x</returns> public static double Exp(double x) { double c; int n = 1; double ex = 1F; double m = 1F; // exp(x+y) = exp(x) * exp(y) // http://www.quinapalus.com/efunc.html while (x > 10.000F) { m *= 22026.4657948067; x -= 10F; } while (x > 01.000F) { m *= E; x -= 1F; } while (x > 00.100F) { m *= 1.10517091807565; x -= 0.1F; } while (x > 00.010F) { m *= 1.01005016708417; x -= 0.01F; } // if (Abs(x) < (double.Epsilon * 2)) return m; // Uses Taylor series // http://www.mathreference.com/ca,tfn.html for (int y = 1; y <= 4; y++) { c = _power(x, y); ex += c / (double)n; n *= (y + 1); } return ex * m; } /// <summary> /// Returns a specified number raised to the specified power /// </summary> /// <param name="x">number to be raised to a power</param> /// <param name="y">number that specifies a power</param> /// <returns>x raised to the power y</returns> public static double Pow(double x, double y) { double temp = 0F; long l; if (x <= 0.0F) { if (x == 0.0F) { if (y <= 0.0F) throw new ArgumentException(); } l = (long)Floor(y); if (l != y) temp = Exp(y * Log(-x)); if ((l % 2) == 1) temp = -temp; return (temp); } return (Exp(y * Log(x))); } /// <summary> /// Returns the largest integer less than or equal to the specified number. /// </summary> /// <param name="x">a Number</param> /// <returns>the largest integer less than or equal to x</returns> public static double Floor(double x) { return System.Math.Floor(x); } /// <summary> /// Returns the natural (base e) logarithm of a specified number /// </summary> /// <param name="x">a Number</param> /// <returns>Logaritmic of x</returns> public static double Log(double x) { return Log(x, System.Math.E); } /// <summary> /// Calculate logaritmic value from value with given base /// </summary> /// <param name="x">a Number</param> /// <param name="newBase">Base to use</param> /// <returns>Logaritmic of x</returns> public static double Log(double x, double newBase) { // Based on Python sourcecode from: // http://en.literateprograms.org/Logarithm_Function_%28Python%29 double partial = 0.5F; double integer = 0F; double fractional = 0.0F; if (x == 0.0F) return double.NegativeInfinity; if ((x < 1.0F) & (newBase < 1.0F)) throw new ArgumentOutOfRangeException("can't compute Log"); while (x < 1.0F) { integer -= 1F; x *= newBase; } while (x >= newBase) { integer += 1F; x /= newBase; } x *= x; while (partial >= double.Epsilon) { if (x >= newBase) { fractional += partial; x = x / newBase; } partial *= 0.5F; x *= x; } return (integer + fractional); } /// <summary> /// Returns the base 10 logarithm of a specified number. /// </summary> /// <param name="x">a Number </param> /// <returns>Logaritmic of x</returns> public static double Log10(double x) { return Log(x, 10F); } /// <summary> /// Returns the larger of two specified numbers /// </summary> /// <param name="x">a Number</param> /// <param name="y">a Number</param> /// <returns>The larger of two specified numbers</returns> public static double Max(double x, double y) { if (x >= y) return x; else return y; } /// <summary> /// Returns the smaller of two specified numbers /// </summary> /// <param name="x">a Number</param> /// <param name="y">a Number</param> /// <returns>The smaller of two specified numbers</returns> public static double Min(double x, double y) { if (x <= y) return x; else return y; } /// <summary> /// Returns the hyperbolic sine of the specified angle. /// </summary> /// <param name="x">An angle, measured in radians</param> /// <returns>The hyperbolic sine of x</returns> public static double Sinh(double x) { if (x < 0F) x = -x; if (x <= 22F) { double Ex_1 = Tanh(x / 2) * (Exp(x) + 1); return ((Ex_1 + (Ex_1 / (Ex_1 - 1))) / 2); } else { return (Exp(x) / 2); } } /// <summary> /// Returns a value indicating the sign /// </summary> /// <param name="x">A signed number.</param> /// <returns>A number indicating the sign of x</returns> public static double Sign(double x) { if (x < 0F) return -1; else if (x == 0F) return 0; else return 1; } /// <summary> /// Calculate Sinus /// </summary> /// <param name="x">Value</param> /// <returns>Sinus of Value</returns> public static double Sin(double x) { return Cos((System.Math.PI / 2.0F) - x); } /// <summary> /// Returns the square root of a specified number /// </summary> /// <param name="x">A number</param> /// <returns>square root of x</returns> public static double Sqrt(double x) { double i = 0; double x1 = 0.0F; double x2 = 0.0F; if (x == 0F) return 0F; while ((i * i) <= x) i += 0.1F; x1 = i; for (int j = 0; j < 10; j++) { x2 = x; x2 /= x1; x2 += x1; x2 /= 2; x1 = x2; } return x2; } /// <summary> /// Calculate Tangens /// </summary> /// <param name="x">Value</param> /// <returns>Tangens of Value</returns> public static double Tan(double x) { return (Sin(x) / Cos(x)); } /// <summary> /// Returns the hyperbolic tangent of the specified angle /// </summary> /// <param name="x">An angle, measured in radians</param> /// <returns>The hyperbolic tangent of x</returns> public static double Tanh(double x) { return (expm1(2F * x) / (expm1(2F * x) + 2F)); } /// <summary> /// Calculates the integral part of x to the nearest integer towards zero. /// </summary> /// <param name="x">A number to truncate</param> /// <returns>integral part of x</returns> public static double Truncate(double x) { if (x == 0F) return 0F; else if (x > 0F) return Floor(x); else return Ceiling(x); } /// <summary> /// Returns angle in [0..360) range /// /// </summary> /// <param name="d">An angle in radians</param> public static double RadiansToDegrees(double d) { double result = (360 * d) / (2 * MathEX.PI); while (result < 0) result += 360; while (result >= 360) result -= 360; return result; } #region Internaly used functions private static double expm1(double x) { double u = Exp(x); if (u == 1.0F) return x; if (u - 1.0F == -1.0F) return -1.0F; return (u - 1.0F) * x / Log(u); } private static double _power(double x, int c) { if (c == 0) return 1.0F; double ret = x; if (c >= 0f) { for (int _c = 1; _c < c; _c++) ret *= ret; } else { for (int _c = 1; _c < c; _c++) ret /= ret; } return ret; } private static double atans(double x) { if (x < sq2m1) return (atanx(x)); else if (x > sq2p1) return (pio2 - atanx(1.0F / x)); else return (pio4 + atanx((x - 1.0F) / (x + 1.0F))); } private static double atanx(double x) { double argsq; double value; argsq = x * x; value = ((((atan_p4 * argsq + atan_p3) * argsq + atan_p2) * argsq + atan_p1) * argsq + atan_p0); value = value / (((((argsq + atan_q4) * argsq + atan_q3) * argsq + atan_q2) * argsq + atan_q1) * argsq + atan_q0); return (value * x); } #endregion }
