skyview.util
Class Utilities

java.lang.Object
  skyview.util.Utilities

public class Utilities
extends java.lang.Object

utlity functions to use with SkyView

Constructor Summary

Utilities()

Method Summary

static double	adjustCoordX(double c) Ensure that a value is in the region -PI to PI.
static double	adjustCoordY(double c) Ensure that a value is in the approrpiate range from -PI/2 to PI/2.
static double	angularDistance(double cx1, double cy1, double cx2, double cy2) Calculates angular distance between two points on a sphere.
static double[]	average3dData(double[][] data) Average a 2-D array over it's first dimension.
static double	convertNotation(java.lang.String str) Handle exponential notation.
static double	maxInArray(double[] d) Find the maximum value of a double array.
static int	maxInArray(int[] d) Find the maximum value in an integer array
static double	minInArray(double[] d) Find the minimum value of an array.
static double[]	minMaxInArray(double[] d) The the extremum values in an array
static java.lang.String	sexagesimal(double value, int precision) Format a sexagesimal coordinate string.
static int[]	whereInArray(double[] d, double searchValue) Find the indices of a double array that are equal a given value.
static int[]	whereInArray(double[] d, java.lang.String operation, double searchValue) Find the indices of a double array that satisfy the given criterion.
static int[]	whereNaNInArray(double[] d) Find the indices of a double array that are NaNs.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Utilities

public Utilities()

Method Detail

angularDistance

public static double angularDistance(double cx1,
                                     double cy1,
                                     double cx2,
                                     double cy2)

Calculates angular distance between two points on a sphere. All angles are measured in degrees.

Parameters:

cx1 - Longitude like coordinate of first point

cy1 - Latitude like coordinate of first point

cx2 - Longitude like coordinate of second point

cy1 - Latitude like coordinate of second point

Returns:

distance between the two points in degrees

minMaxInArray

public static double[] minMaxInArray(double[] d)

The the extremum values in an array

Parameters:

d - An array of doubles

Returns:

An array with two elements giving the min and max of the array. Returns null if the array is not defined or has zero length.

maxInArray

public static int maxInArray(int[] d)

Find the maximum value in an integer array

Parameters:

d - Array to be checked

Returns:

The maximum or the smallest integer value if d is null or of zero length.

maxInArray

public static double maxInArray(double[] d)

Find the maximum value of a double array.

Parameters:

d - The array to be checked

Returns:

The maximum value or NaN if the array is undefined or of zero length

minInArray

public static double minInArray(double[] d)

Find the minimum value of an array.

Parameters:

d - The array to be checked.

Returns:

The minimum value or NaN if the array is null or of zero length.

adjustCoordX

public static double adjustCoordX(double c)

Ensure that a value is in the region -PI to PI. This is appropriate for longitude like coordinates.

Parameters:

c - The input value.

Returns:

The value adjusted to the proper range.

adjustCoordY

public static double adjustCoordY(double c)

Ensure that a value is in the approrpiate range from -PI/2 to PI/2. This is appropriate for latitude like coordinates. Note that the behavior is appropriate for going 'over' the pole. However, this should really be called in conjunction with the longitude like coordinate. E.g., (using degrees for clarity) we'd want:

(0, -91) -> (180, -89)

but this only addresses the latitudes.

Parameters:

c - The input value.

Returns:

The value adjusted to the proper range.

whereNaNInArray

public static int[] whereNaNInArray(double[] d)

Find the indices of a double array that are NaNs.

Parameters:

d - The array

searchValue - Value searched for.

Returns:

Array of indices where value is found

whereInArray

public static int[] whereInArray(double[] d,
                                 double searchValue)

Find the indices of a double array that are equal a given value.

Parameters:

d - The array

searchValue - Value searched for.

Returns:

Array of indices where value is found

whereInArray

public static int[] whereInArray(double[] d,
                                 java.lang.String operation,
                                 double searchValue)

Find the indices of a double array that satisfy the given criterion.

Parameters:

d - The array

operation - Looking for equality, <, or >.

searchValue - Value searched for.

Returns:

Array of indices where value is found

convertNotation

public static double convertNotation(java.lang.String str)

Handle exponential notation.

Parameters:

str - Input string

Returns:

The string converted to a double precision value.

sexagesimal

public static java.lang.String sexagesimal(double value,
                                           int precision)

Format a sexagesimal coordinate string.

Parameters:

value - A double precision value which is to be converted to a string representation. The user should convert to hours prior to this call if needed.

precision - A integer value giving the precision to which the value is to be shown.

&le= 0

Degrees (or hours), e.g. 24

1

Deg.f e.g., 24.3

2

Deg mm e.g., 24 18

3

Deg mm.f e.g., 25 18.3

4

Deg mm ss e.g., 25 18 18

5

Deg mm ss.s e.g., 25 18 18.2

6

Deg mm ss.ss e.g., 25 18 18.24

>6

Deg mm ss.sss e.g., 25 18 18.238

average3dData

public static double[] average3dData(double[][] data)

Average a 2-D array over it's first dimension. The array is assumed to be square. In practice the first dimension will be an energy dimension, while the spatial dimensions will both be incorporated in the second index.

Parameters:

data - The array to be averaged.

Returns:

The averaged array.