SloppyMath

java.lang.Object
- org.apache.lucene.util.SloppyMath

public class SloppyMath
extends java.lang.Object

Math functions that trade off accuracy for speed.

Field Summary

Fields
Modifier and Type	Field and Description
`private static double`	`ASIN_DELTA`
`private static double`	`ASIN_INDEXER`
`private static double`	`ASIN_MAX_VALUE_FOR_TABS`
`private static double`	`ASIN_PIO2_HI`
`private static double`	`ASIN_PIO2_LO`
`private static double`	`ASIN_PS0`
`private static double`	`ASIN_PS1`
`private static double`	`ASIN_PS2`
`private static double`	`ASIN_PS3`
`private static double`	`ASIN_PS4`
`private static double`	`ASIN_PS5`
`private static double`	`ASIN_QS1`
`private static double`	`ASIN_QS2`
`private static double`	`ASIN_QS3`
`private static double`	`ASIN_QS4`
`private static int`	`ASIN_TABS_SIZE`
`private static double[]`	`asinDer1DivF1Tab`
`private static double[]`	`asinDer2DivF2Tab`
`private static double[]`	`asinDer3DivF3Tab`
`private static double[]`	`asinDer4DivF4Tab`
`private static double[]`	`asinTab`
`private static double[]`	`cosTab`
`private static double`	`ONE_DIV_F2`
`private static double`	`ONE_DIV_F3`
`private static double`	`ONE_DIV_F4`
`private static double`	`PIO2_HI`
`private static double`	`PIO2_LO`
`private static double`	`SIN_COS_DELTA_HI`
`private static double`	`SIN_COS_DELTA_LO`
`private static double`	`SIN_COS_INDEXER`
`(package private) static double`	`SIN_COS_MAX_VALUE_FOR_INT_MODULO`
`private static int`	`SIN_COS_TABS_SIZE`
`private static double[]`	`sinTab`
`static double`	`TO_DEGREES`
`private static double`	`TO_KILOMETERS`
`private static double`	`TO_METERS`
`static double`	`TO_RADIANS`
`private static double`	`TWOPI_HI`
`private static double`	`TWOPI_LO`

Constructor Summary

Constructors
Constructor and Description

SloppyMath()

Constructors
Constructor and Description
`SloppyMath()`

Method Summary

All Methods Static Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`static double`	`asin(double a)` Returns the arc sine of a value.
`static double`	`cos(double a)` Returns the trigonometric cosine of an angle.
`static double`	`haversinKilometers(double lat1, double lon1, double lat2, double lon2)` Deprecated. Use `instead`
`static double`	`haversinMeters(double sortKey)` Returns the Haversine distance in meters between two points given the previous result from `haversinSortKey(double, double, double, double)`
`static double`	`haversinMeters(double lat1, double lon1, double lat2, double lon2)` Returns the Haversine distance in meters between two points specified in decimal degrees (latitude/longitude).
`static double`	`haversinSortKey(double lat1, double lon1, double lat2, double lon2)` Returns a sort key for distance.
`static double`	`toDegrees(double radians)` Convert to degrees.
`static double`	`toRadians(double degrees)` Convert to radians.

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

- Field Detail
  - TO_RADIANS
```
public static final double TO_RADIANS
```
    See Also:
    
    Constant Field Values
  - TO_DEGREES
```
public static final double TO_DEGREES
```
    See Also:
    
    Constant Field Values
  - TO_METERS
```
private static final double TO_METERS
```
    See Also:
    
    Constant Field Values
  - TO_KILOMETERS
```
private static final double TO_KILOMETERS
```
    See Also:
    
    Constant Field Values
  - ONE_DIV_F2
```
private static final double ONE_DIV_F2
```
    See Also:
    
    Constant Field Values
  - ONE_DIV_F3
```
private static final double ONE_DIV_F3
```
    See Also:
    
    Constant Field Values
  - ONE_DIV_F4
```
private static final double ONE_DIV_F4
```
    See Also:
    
    Constant Field Values
  - PIO2_HI
```
private static final double PIO2_HI
```
  - PIO2_LO
```
private static final double PIO2_LO
```
  - TWOPI_HI
```
private static final double TWOPI_HI
```
  - TWOPI_LO
```
private static final double TWOPI_LO
```
  - SIN_COS_TABS_SIZE
```
private static final int SIN_COS_TABS_SIZE
```
    See Also:
    
    Constant Field Values
  - SIN_COS_DELTA_HI
```
private static final double SIN_COS_DELTA_HI
```
  - SIN_COS_DELTA_LO
```
private static final double SIN_COS_DELTA_LO
```
  - SIN_COS_INDEXER
```
private static final double SIN_COS_INDEXER
```
  - sinTab
```
private static final double[] sinTab
```
  - cosTab
```
private static final double[] cosTab
```
  - SIN_COS_MAX_VALUE_FOR_INT_MODULO
```
static final double SIN_COS_MAX_VALUE_FOR_INT_MODULO
```
  - ASIN_MAX_VALUE_FOR_TABS
```
private static final double ASIN_MAX_VALUE_FOR_TABS
```
  - ASIN_TABS_SIZE
```
private static final int ASIN_TABS_SIZE
```
    See Also:
    
    Constant Field Values
  - ASIN_DELTA
```
private static final double ASIN_DELTA
```
  - ASIN_INDEXER
```
private static final double ASIN_INDEXER
```
  - asinTab
```
private static final double[] asinTab
```
  - asinDer1DivF1Tab
```
private static final double[] asinDer1DivF1Tab
```
  - asinDer2DivF2Tab
```
private static final double[] asinDer2DivF2Tab
```
  - asinDer3DivF3Tab
```
private static final double[] asinDer3DivF3Tab
```
  - asinDer4DivF4Tab
```
private static final double[] asinDer4DivF4Tab
```
  - ASIN_PIO2_HI
```
private static final double ASIN_PIO2_HI
```
  - ASIN_PIO2_LO
```
private static final double ASIN_PIO2_LO
```
  - ASIN_PS0
```
private static final double ASIN_PS0
```
  - ASIN_PS1
```
private static final double ASIN_PS1
```
  - ASIN_PS2
```
private static final double ASIN_PS2
```
  - ASIN_PS3
```
private static final double ASIN_PS3
```
  - ASIN_PS4
```
private static final double ASIN_PS4
```
  - ASIN_PS5
```
private static final double ASIN_PS5
```
  - ASIN_QS1
```
private static final double ASIN_QS1
```
  - ASIN_QS2
```
private static final double ASIN_QS2
```
  - ASIN_QS3
```
private static final double ASIN_QS3
```
  - ASIN_QS4
```
private static final double ASIN_QS4
```
- Constructor Detail
  - SloppyMath
```
public SloppyMath()
```
- Method Detail
  - haversinMeters
```
public static double haversinMeters(double lat1,
                                    double lon1,
                                    double lat2,
                                    double lon2)
```
    Returns the Haversine distance in meters between two points specified in decimal degrees (latitude/longitude). This works correctly even if the dateline is between the two points.
    Error is at most 4E-1 (40cm) from the actual haversine distance, but is typically much smaller for reasonable distances: around 1E-5 (0.01mm) for distances less than 1000km.
    
    Parameters:
    
    lat1 - Latitude of the first point.
    
    lon1 - Longitude of the first point.
    
    lat2 - Latitude of the second point.
    
    lon2 - Longitude of the second point.
    
    Returns:
    
    distance in meters.
  - haversinMeters
```
public static double haversinMeters(double sortKey)
```
    Returns the Haversine distance in meters between two points given the previous result from haversinSortKey(double, double, double, double)
    
    Returns:
    
    distance in meters.
  - haversinKilometers
```
@Deprecated
public static double haversinKilometers(double lat1,
                                                    double lon1,
                                                    double lat2,
                                                    double lon2)
```
    Deprecated. Use instead
    
    Returns the Haversine distance in kilometers between two points specified in decimal degrees (latitude/longitude). This works correctly even if the dateline is between the two points.
    
    Parameters:
    
    lat1 - Latitude of the first point.
    
    lon1 - Longitude of the first point.
    
    lat2 - Latitude of the second point.
    
    lon2 - Longitude of the second point.
    
    Returns:
    
    distance in kilometers.
  - haversinSortKey
```
public static double haversinSortKey(double lat1,
                                     double lon1,
                                     double lat2,
                                     double lon2)
```
    Returns a sort key for distance. This is less expensive to compute than haversinMeters(double, double, double, double), but it always compares the same. This can be converted into an actual distance with haversinMeters(double), which effectively does the second half of the computation.
  - cos
```
public static double cos(double a)
```
    Returns the trigonometric cosine of an angle.
    Error is around 1E-15.
    Special cases:
    - If the argument is NaN or an infinity, then the result is NaN.
    Parameters:
    
    a - an angle, in radians.
    
    Returns:
    
    the cosine of the argument.
    
    See Also:
    
    Math.cos(double)
  - asin
```
public static double asin(double a)
```
    Returns the arc sine of a value.
    The returned angle is in the range -pi/2 through pi/2. Error is around 1E-7.
    Special cases:
    - If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
    Parameters:
    
    a - the value whose arc sine is to be returned.
    
    Returns:
    
    arc sine of the argument
    
    See Also:
    
    Math.asin(double)
  - toDegrees
```
public static double toDegrees(double radians)
```
    Convert to degrees.
    
    Parameters:
    
    radians - radians to convert to degrees
    
    Returns:
    
    degrees
  - toRadians
```
public static double toRadians(double degrees)
```
    Convert to radians.
    
    Parameters:
    
    degrees - degrees to convert to radians
    
    Returns:
    
    radians

Class SloppyMath

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

TO_RADIANS

TO_DEGREES

TO_METERS

TO_KILOMETERS

ONE_DIV_F2

ONE_DIV_F3

ONE_DIV_F4

PIO2_HI

PIO2_LO

TWOPI_HI

TWOPI_LO

SIN_COS_TABS_SIZE

SIN_COS_DELTA_HI

SIN_COS_DELTA_LO

SIN_COS_INDEXER

sinTab

cosTab

SIN_COS_MAX_VALUE_FOR_INT_MODULO

ASIN_MAX_VALUE_FOR_TABS

ASIN_TABS_SIZE

ASIN_DELTA

ASIN_INDEXER

asinTab

asinDer1DivF1Tab

asinDer2DivF2Tab

asinDer3DivF3Tab

asinDer4DivF4Tab

ASIN_PIO2_HI

ASIN_PIO2_LO

ASIN_PS0

ASIN_PS1

ASIN_PS2

ASIN_PS3

ASIN_PS4

ASIN_PS5

ASIN_QS1

ASIN_QS2

ASIN_QS3

ASIN_QS4

Constructor Detail

SloppyMath

Method Detail

haversinMeters

haversinMeters

haversinKilometers

haversinSortKey

cos

asin

toDegrees

toRadians