## org.apache.lucene.util Class SloppyMath

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

`public class SloppyMathextends Object`

Math functions that trade off accuracy for speed.

Constructor Summary
`SloppyMath()`

Method Summary
`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` `earthDiameter(double latitude)`
Return an approximate value of the diameter of the earth at the given latitude, in kilometers.
`static double` ```haversin(double lat1, double lon1, double lat2, double lon2)```
Returns the distance in kilometers between two points specified in decimal degrees (latitude/longitude).

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

Constructor Detail

### SloppyMath

`public SloppyMath()`
Method Detail

### haversin

```public static double haversin(double lat1,
double lon1,
double lat2,
double lon2)```
Returns the distance in kilometers between two points specified in decimal degrees (latitude/longitude).

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.

### 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)`

### earthDiameter

`public static double earthDiameter(double latitude)`
Return an approximate value of the diameter of the earth at the given latitude, in kilometers.

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