FastRfUtils (Fiji Javadocs 0-SNAPSHOT API)

java.lang.Object
- hr.irb.fastRandomForest.FastRfUtils

```
public final class FastRfUtils
extends Object
```
Utility functions for sorting float (single-precision) arrays, and for normalizing double arrays. Adapted from weka.core.Utils, version 1.57.

Author:

Eibe Frank - original code, Yong Wang - original code, Len Trigg - original code, Julien Prados - original code, Fran Supek (fran.supek[AT]irb.hr) - adapted code

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`normalize(double[] doubles)` Normalizes the doubles in the array by their sum.
`static int[]`	`randomPermutation(int numElems, Random rng)` Produces a random permutation using Knuth shuffle.
`static Instances`	`readInstances(String location)` Load a dataset into memory.
`static Instances`	`scramble(Instances src, Instances dst, int attIndex, int[] perm)` Produces a random permutation of the values of an attribute in a dataset using Knuth shuffle.
`static int[]`	`sort(float[] array)` Sorts a given array of floats in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array.

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

- Method Detail
  - sort
```
public static int[] sort(float[] array)
```
    Sorts a given array of floats in ascending order and returns an array of integers with the positions of the elements of the original array in the sorted array. NOTE THESE CHANGES: the sort is no longer stable and it doesn't use safe floating-point comparisons anymore. Occurrences of Double.NaN behave unpredictably in sorting.
    
    Parameters:
    
    array - this array is not changed by the method!
    
    Returns:
    
    an array of integers with the positions in the sorted array.
  - normalize
```
public static void normalize(double[] doubles)
```
    Normalizes the doubles in the array by their sum.
    If supplied an array full of zeroes, does not modify the array.
    
    Parameters:
    
    doubles - the array of double
    
    Throws:
    
    IllegalArgumentException - if sum is NaN
  - randomPermutation
```
public static int[] randomPermutation(int numElems,
                                      Random rng)
```
    Produces a random permutation using Knuth shuffle.
    
    Parameters:
    
    numElems - the size of the permutation
    
    rng - the random number generator
    
    Returns:
    
    a random permutation
  - scramble
```
public static Instances scramble(Instances src,
                                 Instances dst,
                                 int attIndex,
                                 int[] perm)
```
    Produces a random permutation of the values of an attribute in a dataset using Knuth shuffle.
    Copies back the current values of the previously scrambled attribute and uses the given permutation to scramble the values of the new attribute all by copying from the original dataset.
    
    Parameters:
    
    src - the source dataset
    
    dst - the scrambled dataset
    
    attIndex - the attribute index
    
    perm - the random permutation
    
    Returns:
    
    fluent
  - readInstances
```
public static Instances readInstances(String location)
                               throws Exception
```
    Load a dataset into memory.
    
    Parameters:
    
    location - the location of the dataset
    
    Returns:
    
    the dataset
    
    Throws:
    
    Exception

Class FastRfUtils

Method Summary

Methods inherited from class java.lang.Object

Method Detail

sort

normalize

randomPermutation

scramble

readInstances