Class MathUtil

Various utility functions for mathematical and numerical operations.

Inheritance

object

MathUtil

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: NetTopologySuite.Mathematics

Assembly: NetTopologySuite.dll

Syntax

public class MathUtil

Fields

PhiInv

The inverse of the Golden Ratio phi.

Declaration

public static readonly double PhiInv

Field Value

Type	Description
double

Methods

Average(double, double)

Computes the average of two numbers.

Declaration

public static double Average(double x1, double x2)

Parameters

Type	Name	Description
double	x1	A number
double	x2	A number

Returns

Type	Description
double	The average of the inputs

Ceiling(int, int)

Computes the ceiling function of the dividend of two integers.

Declaration

public static int Ceiling(int num, int denom)

Parameters

Type	Name	Description
int	num	The numerator
int	denom	The denominator

Returns

Type	Description
int	The ceiling of num / denom

Clamp(double, double, double)

Clamps a double value to a given range.

Declaration

public static double Clamp(double x, double min, double max)

Parameters

Type	Name	Description
double	x	The value to clamp
double	min	The minimum value of the range
double	max	The maximum value of the range

Returns

Type	Description
double	The clamped value

Clamp(int, int, int)

Clamps a int value to a given range.

Declaration

public static int Clamp(int x, int min, int max)

Parameters

Type	Name	Description
int	x	The value to clamp
int	min	The minimum value of the range
int	max	The maximum value of the range

Returns

Type	Description
int	The clamped value

ClampMax(int, int)

Clamps an integer to a given maximum limit.

Declaration

public static int ClampMax(int x, int max)

Parameters

Type	Name	Description
int	x	The value to clamp
int	max	The maximum value of the range

Returns

Type	Description
int	The clamped value

Log10(double)

Computes the base-10 logarithm of a double value.

• If the argument is NaN or less than zero, then the result is NaN.
• If the argument is positive infinity, then the result is positive infinity.
• If the argument is positive zero or negative zero, then the result is negative infinity.

Declaration

public static double Log10(double x)

Parameters

Type	Name	Description
double	x	A positive number

Returns

Type	Description
double	The value log a, the base-10 logarithm of the input value

Max(double, double, double)

Computes the maximum fo three values

Declaration

public static double Max(double v1, double v2, double v3)

Parameters

Type	Name	Description
double	v1	A number
double	v2	A number
double	v3	A number

Returns

Type	Description
double	The maximum value of v1, v2 and v3

Max(double, double, double, double)

Computes the maximum of four values

Declaration

public static double Max(double v1, double v2, double v3, double v4)

Parameters

Type	Name	Description
double	v1	A number
double	v2	A number
double	v3	A number
double	v4	A number

Returns

Type	Description
double	The maximum value of v1, v2, v3 and v4

Min(double, double, double)

Computes the minimum of four values

Declaration

public static double Min(double v1, double v2, double v3)

Parameters

Type	Name	Description
double	v1	A number
double	v2	A number
double	v3	A number

Returns

Type	Description
double	The minimum value of v1, v2 and v3

Min(double, double, double, double)

Computes the minimum of four values

Declaration

public static double Min(double v1, double v2, double v3, double v4)

Parameters

Type	Name	Description
double	v1	A number
double	v2	A number
double	v3	A number
double	v4	A number

Returns

Type	Description
double	The minimum value of v1, v2, v3 and v4

QuasiRandom(double)

Generates a quasi-random sequence of numbers in the range [0,1]. They are produced by an additive recurrence with 1/φ as the constant. This produces a low-discrepancy sequence which is more evenly distribute than random numbers.

See Wikipedia: Low-discrepancy Sequences - Additive Recurrence.

The sequence is initialized by calling it with any positive fractional number; 0 works well for most uses.

Declaration

public static double QuasiRandom(double curr)

Parameters

Type	Name	Description
double	curr	The current number in the sequence

Returns

Type	Description
double	The next value in the sequence

QuasiRandom(double, double)

Generates a quasi-random sequence of numbers in the range [0,1]. They are produced by an additive recurrence with constant α.

R(α) :  tn = { t0 + nα },  n = 1,2,3,...

When α is irrational this produces a Low discrepancy sequence which is more evenly distributed than random numbers.

The sequence is initialized by calling it with any positive fractional number. 0 works well for most uses.

Declaration

public static double QuasiRandom(double curr, double alpha)

Parameters

Type	Name	Description
double	curr	The current number in the sequence
double	alpha	the sequence's additive constant

Returns

Type	Description
double	The next value in the sequence

Shuffle(int)

Generates a randomly-shuffled list of the integers from [0..n-1].

One use is to randomize points inserted into a KdTree<T>.

Declaration

public static int[] Shuffle(int n)

Parameters

Type	Name	Description
int	n	The number of integers to shuffle

Returns

Type	Description
int[]	The shuffled array

Wrap(int, int)

Computes an index which wraps around a given maximum value. For values >= 0, this is equals to val % max. For values < 0, this is equal to max - (-val) % max

Declaration

public static int Wrap(int index, int max)

Parameters

Type	Name	Description
int	index	The index to wrap
int	max	The maximum value (or modulus)

Returns

Type	Description
int	The wrapped index