MathUtils (SNAP Engine API)

java.lang.Object
- org.esa.snap.core.util.math.MathUtils

```
public class MathUtils
extends Object
```
A utility class providing frequently used mathematical functions which are not found in the java.lang.Math class.
All functions have been implemented with extreme caution in order to provide a maximum performance.

Version:

$Revision$ $Date$

Field Summary

Fields
Modifier and Type	Field and Description
`static double`	`DTOR` Conversion factor for degrees to radians for the `double` data type.
`static float`	`DTOR_F` Conversion factor for degrees to radians for the `float` data type.
`static double`	`EPS` The epsilon value for the `double` data type.
`static float`	`EPS_F` The epsilon value for the `float` data type.
`static double`	`HALFPI` Pi half
`static double`	`LOG10` The natural logarithm of 10 as given by `Math.logging(10)`
`static double`	`RTOD` Conversion factor for radians to degrees for the `double` data type.
`static float`	`RTOD_F` Conversion factor for radians to degrees for the `float` data type.

Constructor Summary

Constructors
Constructor and Description

MathUtils()

Constructors
Constructor and Description
`MathUtils()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static int`	`ceilInt(double x)` Returns `(int) Math.ceil(x)`.
`static long`	`ceilLong(double x)` Returns `(long) Math.ceil(x)`.
`static double`	`computeRoundFactor(double min, double max, int numDigits)` Computes a rounding factor suitable for the given value range and number of significant digits after the decimal point.
`static float`	`computeRoundFactor(float min, float max, int numDigits)` Computes a rounding factor suitable for the given value range and number of significant digits.
`static byte[]`	`createGammaCurve(double gamma, byte[] f)` Creates a quantized gamma (correction) curve for 256 samples in range from `0` to `1`.
`static byte`	`crop(byte val, byte min, byte max)` Crops the value to the range `min` to `max`.
`static double`	`crop(double val, double min, double max)` Crops the value to the range `min` to `max`.
`static float`	`crop(float val, float min, float max)` Crops the value to the range `min` to `max`.
`static int`	`crop(int val, int min, int max)` Crops the value to the range `min` to `max`.
`static long`	`crop(long val, long min, long max)` Crops the value to the range `min` to `max`.
`static short`	`crop(short val, short min, short max)` Crops the value to the range `min` to `max`.
`static boolean`	`equalValues(double x1, double x2)` Compares two double values for equality within the fixed epsilon.
`static boolean`	`equalValues(double x1, double x2, double eps)` Compares two double values for equality within the given epsilon.
`static boolean`	`equalValues(float x1, float x2)` Compares two float values for equality within the fixed epsilon.
`static boolean`	`equalValues(float x1, float x2, float eps)` Compares two float values for equality within the given epsilon.
`static Dimension`	`fitDimension(int n, double a, double b)` Computes an integer dimension for a given integer area that best fits the rectangle given by floating point width and height.
`static int`	`floorAndCrop(double x, int min, int max)` First calls `Math.floor` with `x` and then crops the resulting value to the range `min` to `max`.
`static int`	`floorInt(double value)` Returns `(int) Math.floor(value)`.
`static long`	`floorLong(double x)` Returns `(long) Math.floor(x)`.
`static double`	`getOrderOfMagnitude(double x)` Returns the order of magnitude for the value `x`.
`static double`	`interpolate2D(double wi, double wj, double x00, double x10, double x01, double x11)` Performs a fast linear interpolation in two dimensions i and j.
`static float`	`interpolate2D(float wi, float wj, float x00, float x10, float x01, float x11)` Performs a fast linear interpolation in two dimensions i and j.
`static double`	`log10(double x)` Computes the common logarithm (to the base 10).
`static double`	`round(double x, double roundFactor)` Computes a rounded value for the given rounding factor.
`static float`	`round(float x, float roundFactor)` Computes a rounded value for the given rounding factor.
`static long`	`roundAndCrop(double value, long min, long max)` First calls `Math.round` with `value` and then crops the resulting value to the range `min` to `max`.
`static int`	`roundAndCrop(float x, int min, int max)` First calls `Math.round` with `x` and then crops the resulting value to the range `min` to `max`.
`static double`	`sphereDistance(double sphereRadius, double lambda1_rad, double phi1_rad, double lambda2_rad, double phi2_rad)`
`static double`	`sphereDistanceDeg(double sphereRadius, double lambda1_deg, double phi1_deg, double lambda2_deg, double phi2_deg)`
`static Rectangle[]`	`subdivideRectangle(int width, int height, int numTilesX, int numTilesY, int extraBorder)` Subdivides a rectangle into tiles.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - EPS_F
```
public static final float EPS_F
```
    The epsilon value for the float data type. The exact value of this constant is 1.0E-6.
    
    See Also:
    
    Constant Field Values
  - EPS
```
public static final double EPS
```
    The epsilon value for the double data type. The exact value of this constant is 1.0E-12.
    
    See Also:
    
    Constant Field Values
  - DTOR
```
public static final double DTOR
```
    Conversion factor for degrees to radians for the double data type.
    
    See Also:
    
    Constant Field Values
  - RTOD
```
public static final double RTOD
```
    Conversion factor for radians to degrees for the double data type.
    
    See Also:
    
    Constant Field Values
  - DTOR_F
```
public static final float DTOR_F
```
    Conversion factor for degrees to radians for the float data type.
    
    See Also:
    
    Constant Field Values
  - RTOD_F
```
public static final float RTOD_F
```
    Conversion factor for radians to degrees for the float data type.
    
    See Also:
    
    Constant Field Values
  - LOG10
```
public static final double LOG10
```
    The natural logarithm of 10 as given by Math.logging(10)
  - HALFPI
```
public static final double HALFPI
```
    Pi half
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - MathUtils
```
public MathUtils()
```
- Method Detail
  - equalValues
```
public static boolean equalValues(float x1,
                                  float x2)
```
    Compares two float values for equality within the fixed epsilon.
    
    Parameters:
    
    x1 - the first value
    
    x2 - the second value
  - equalValues
```
public static boolean equalValues(double x1,
                                  double x2)
```
    Compares two double values for equality within the fixed epsilon.
    
    Parameters:
    
    x1 - the first value
    
    x2 - the second value
  - equalValues
```
public static boolean equalValues(float x1,
                                  float x2,
                                  float eps)
```
    Compares two float values for equality within the given epsilon.
    
    Parameters:
    
    x1 - the first value
    
    x2 - the second value
    
    eps - the maximum allowed difference
  - equalValues
```
public static boolean equalValues(double x1,
                                  double x2,
                                  double eps)
```
    Compares two double values for equality within the given epsilon.
    
    Parameters:
    
    x1 - the first value
    
    x2 - the second value
    
    eps - the maximum allowed difference
  - interpolate2D
```
public static float interpolate2D(float wi,
                                  float wj,
                                  float x00,
                                  float x10,
                                  float x01,
                                  float x11)
```
    Performs a fast linear interpolation in two dimensions i and j.
    
    Parameters:
    
    wi - weight in i-direction, a weight of 0.0 corresponds to i, 1.0 to i+1
    
    wj - weight in j-direction, a weight of 0.0 corresponds to j, 1.0 to j+1
    
    x00 - first anchor point located at (i,j)
    
    x10 - second anchor point located at (i+1,j)
    
    x01 - third anchor point located at (i,j+1)
    
    x11 - forth anchor point located at (i+1,j+1)
    
    Returns:
    
    the interpolated value
  - interpolate2D
```
public static double interpolate2D(double wi,
                                   double wj,
                                   double x00,
                                   double x10,
                                   double x01,
                                   double x11)
```
    Performs a fast linear interpolation in two dimensions i and j.
    
    Parameters:
    
    wi - weight in i-direction, a weight of 0.0 corresponds to i, 1.0 to i+1
    
    wj - weight in j-direction, a weight of 0.0 corresponds to j, 1.0 to j+1
    
    x00 - first anchor point located at (i,j)
    
    x10 - second anchor point located at (i+1,j)
    
    x01 - third anchor point located at (i,j+1)
    
    x11 - forth anchor point located at (i+1,j+1)
    
    Returns:
    
    the interpolated value
  - floorAndCrop
```
public static int floorAndCrop(double x,
                               int min,
                               int max)
```
    First calls Math.floor with x and then crops the resulting value to the range min to max.
  - roundAndCrop
```
public static int roundAndCrop(float x,
                               int min,
                               int max)
```
    First calls Math.round with x and then crops the resulting value to the range min to max.
  - roundAndCrop
```
public static long roundAndCrop(double value,
                                long min,
                                long max)
```
    First calls Math.round with value and then crops the resulting value to the range min to max.
    
    Parameters:
    
    value - the value to round and crop
    
    min - the minimum value of the crop range
    
    max - the maximum value of the crop range
    
    Returns:
    
    the rounded and cropped value
  - floorInt
```
public static int floorInt(double value)
```
    Returns (int) Math.floor(value).
    
    Parameters:
    
    value - the double value to be converted
    
    Returns:
    
    the integer value corresponding to the floor of value
  - floorLong
```
public static long floorLong(double x)
```
    Returns (long) Math.floor(x).
    
    Parameters:
    
    x - the value to be converted
    
    Returns:
    
    the long integer value corresponding to the floor of x
  - ceilInt
```
public static int ceilInt(double x)
```
    Returns (int) Math.ceil(x).
    
    Parameters:
    
    x - the value to be converted
    
    Returns:
    
    the integer value corresponding to the ceil of x
  - ceilLong
```
public static long ceilLong(double x)
```
    Returns (long) Math.ceil(x).
    
    Parameters:
    
    x - the value to be converted
    
    Returns:
    
    the long value corresponding to the ceil of x
  - computeRoundFactor
```
public static float computeRoundFactor(float min,
                                       float max,
                                       int numDigits)
```
    Computes a rounding factor suitable for the given value range and number of significant digits.
    
    Parameters:
    
    min - the minimum value of the range
    
    max - the maximum value of the range
    
    numDigits - the number of significant digits, must be =0
    
    Returns:
    
    the rounded value, always a power to the base 10
    
    See Also:
    
    round(float, float)
  - computeRoundFactor
```
public static double computeRoundFactor(double min,
                                        double max,
                                        int numDigits)
```
    Computes a rounding factor suitable for the given value range and number of significant digits after the decimal point.
    
    Parameters:
    
    min - the minimum value of the range
    
    max - the maximum value of the range
    
    numDigits - the number of significant digits after the decimal point, must be =0
    
    Returns:
    
    the rounded value, always a power to the base 10
    
    See Also:
    
    round(double, double)
  - round
```
public static float round(float x,
                          float roundFactor)
```
    Computes a rounded value for the given rounding factor. The given value is pre-multiplied with the rounding factor, then rounded to the closest int and then again divided by the the rounding factor.
    The rounding factor can be computed for a given value range and accuracy with the computeRoundFactor method.
    
    Parameters:
    
    x - the value to be rounded
    
    roundFactor - the rounding factor specifying the accuracy, should always be a power to the base 10
    
    Returns:
    
    the rounded value
    
    See Also:
    
    computeRoundFactor(float, float, int)
  - round
```
public static double round(double x,
                           double roundFactor)
```
    Computes a rounded value for the given rounding factor. The given value is pre-multiplied with the rounding factor, then rounded to the closest int and then again divided by the the rounding factor.
    The rounding factor can be computed for a given value range and accuracy with the computeRoundFactor method.
    
    Parameters:
    
    x - the value to be rounded
    
    roundFactor - the rounding factor specifying the accuracy, should always be a power to the base 10
    
    Returns:
    
    the rounded value
    
    See Also:
    
    computeRoundFactor(double, double, int)
  - getOrderOfMagnitude
```
public static double getOrderOfMagnitude(double x)
```
    Returns the order of magnitude for the value x.
    
    Parameters:
    
    x - the input
    
    Returns:
    
    the order of magnitude: Math.floor(log10(x))
  - log10
```
public static double log10(double x)
```
    Computes the common logarithm (to the base 10).
    
    Parameters:
    
    x - the input
    
    Returns:
    
    the common logarithm: Math.logging(x)/LOG10
  - createGammaCurve
```
public static byte[] createGammaCurve(double gamma,
                                      byte[] f)
```
    Creates a quantized gamma (correction) curve for 256 samples in range from 0 to 1. The array returned for can be used as a lookup table for gamma transformations. In order to interpret the value correctly use the following code snippet:
```
    byte[] f = MathUtils.createGammaCurve(gamma, null);
    for (int i = 0; i < 256; i++) {
         // transform i --> j
         j = f[i] & 0xff;
         // now use j instead of i
    }
 
```
    Parameters:
    
    gamma - the gamma value, reasonable range is 1/10 to 10, if 1 then each f[i] & 0xff will be i.
    
    f - the curve as an array of length 256. If not null, the method used this array as returen value after values have been written into it. If null, the method creates a new array and returns it.
    
    Returns:
    
    a quantized gamma (correction) curve for 256 samples
  - crop
```
public static byte crop(byte val,
                        byte min,
                        byte max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - crop
```
public static short crop(short val,
                         short min,
                         short max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - crop
```
public static int crop(int val,
                       int min,
                       int max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - crop
```
public static long crop(long val,
                        long min,
                        long max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - crop
```
public static float crop(float val,
                         float min,
                         float max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - crop
```
public static double crop(double val,
                          double min,
                          double max)
```
    Crops the value to the range min to max.
    
    Parameters:
    
    val - the value to crop
    
    min - the minimum crop limit
    
    max - the maximum crop limit
  - fitDimension
```
public static Dimension fitDimension(int n,
                                     double a,
                                     double b)
```
    Computes an integer dimension for a given integer area that best fits the rectangle given by floating point width and height.
    
    Parameters:
    
    n - the integer area
    
    a - the rectangle's width
    
    b - the rectangle's height
    
    Returns:
    
    an integer dimension, never null
  - subdivideRectangle
```
public static Rectangle[] subdivideRectangle(int width,
                                             int height,
                                             int numTilesX,
                                             int numTilesY,
                                             int extraBorder)
```
    Subdivides a rectangle into tiles. The coordinates of each returned tile rectangle are guaranteed to be within the given rectangle.
    
    Parameters:
    
    width - the rectangle's width
    
    height - the rectangle's height
    
    numTilesX - the number of tiles in X direction
    
    numTilesY - the number of tiles in Y direction
    
    extraBorder - an extra border size to extend each tile
    
    Returns:
    
    the tile coordinates as rectangles
  - sphereDistanceDeg
```
public static final double sphereDistanceDeg(double sphereRadius,
                                             double lambda1_deg,
                                             double phi1_deg,
                                             double lambda2_deg,
                                             double phi2_deg)
```
    Parameters:
    
    sphereRadius - the radius of the sphere
    
    lambda1_deg - the lambda angle of point one, in degree
    
    phi1_deg - the phi angle of point one, in degree
    
    lambda2_deg - the lambda angle of point two, in degree
    
    phi2_deg - the phi angle of point one, in degree
    
    Returns:
    
    the distance described by the two given points (lambda/phi) on the top of sphere described by the given radius
  - sphereDistance
```
public static final double sphereDistance(double sphereRadius,
                                          double lambda1_rad,
                                          double phi1_rad,
                                          double lambda2_rad,
                                          double phi2_rad)
```
    Parameters:
    
    sphereRadius - the radius of the sphere
    
    lambda1_rad - the lambda angle of point one, in radians
    
    phi1_rad - the phi angle of point one, in radians
    
    lambda2_rad - the lambda angle of point two, in radians
    
    phi2_rad - the phi angle of point one, in radians
    
    Returns:
    
    the distance described by the two given points (lambda/phi) on the top of sphere described by the given radius

Class MathUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EPS_F

EPS

DTOR

RTOD

DTOR_F

RTOD_F

LOG10

HALFPI

Constructor Detail

MathUtils

Method Detail

equalValues

equalValues

equalValues

equalValues

interpolate2D

interpolate2D

floorAndCrop

roundAndCrop

roundAndCrop

floorInt

floorLong

ceilInt

ceilLong

computeRoundFactor

computeRoundFactor

round

round

getOrderOfMagnitude

log10

createGammaCurve

crop

crop

crop

crop

crop

crop

fitDimension

subdivideRectangle

sphereDistanceDeg

sphereDistance