DoubleBigArrays (fastutil 6.4.1 API)

java.lang.Object
- it.unimi.dsi.fastutil.doubles.DoubleBigArrays

```
public class DoubleBigArrays
extends Object
```
A class providing static methods and objects that do useful things with big arrays.
In particular, the ensureCapacity(), grow(), trim() and setLength() methods allow to handle big arrays much like array lists.
Note that BinIO and TextIO contain several methods make it possible to load and save big arrays of primitive types as sequences of elements in DataInput format (i.e., not as objects) or as sequences of lines of text.

See Also:
BigArrays

Field Summary

Fields
Modifier and Type	Field and Description
`static double[][]`	`EMPTY_BIG_ARRAY` A static, final, empty big array.
`static Hash.Strategy`	`HASH_STRATEGY` A type-specific content-based hash strategy for big arrays.
`static long`	`ONEOVERPHI` The inverse of the golden ratio times 2¹⁶.

Method Summary

Methods
Modifier and Type	Method and Description
`static void`	`add(double[][] array, long index, double incr)` Adds the specified increment the element of the given big array of specified index.
`static long`	`binarySearch(double[][] a, double key)` Searches a big array for the specified value using the binary search algorithm.
`static long`	`binarySearch(double[][] a, double key, DoubleComparator c)` Searches a big array for the specified value using the binary search algorithm and a specified comparator.
`static long`	`binarySearch(double[][] a, long from, long to, double key)` Searches a range of the specified big array for the specified value using the binary search algorithm.
`static long`	`binarySearch(double[][] a, long from, long to, double key, DoubleComparator c)` Searches a range of the specified big array for the specified value using the binary search algorithm and a specified comparator.
`static double[][]`	`copy(double[][] array)` Returns a copy of a big array.
`static void`	`copy(double[][] srcArray, long srcPos, double[][] destArray, long destPos, long length)` Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination big array.
`static double[][]`	`copy(double[][] array, long offset, long length)` Returns a copy of a portion of a big array.
`static void`	`copyFromBig(double[][] srcArray, long srcPos, double[] destArray, int destPos, int length)` Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination array.
`static void`	`copyToBig(double[] srcArray, int srcPos, double[][] destArray, long destPos, long length)` Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination big array.
`static void`	`decr(double[][] array, long index)` Decrements the element of the given big array of specified index.
`static double[][]`	`ensureCapacity(double[][] array, long length)` Ensures that a big array can contain the given number of entries.
`static double[][]`	`ensureCapacity(double[][] array, long length, long preserve)` Ensures that a big array can contain the given number of entries, preserving just a part of the big array.
`static void`	`ensureFromTo(double[][] a, long from, long to)` Ensures that a range given by its first (inclusive) and last (exclusive) elements fits a big array.
`static void`	`ensureOffsetLength(double[][] a, long offset, long length)` Ensures that a range given by an offset and a length fits a big array.
`static boolean`	`equals(double[][] a1, double[][] a2)` Returns true if the two big arrays are elementwise equal.
`static void`	`fill(double[][] array, double value)` Fills the given big array with the given value.
`static void`	`fill(double[][] array, long from, long to, double value)` Fills a portion of the given big array with the given value.
`static double`	`get(double[][] array, long index)` Returns the element of the given big array of specified index.
`static double[][]`	`grow(double[][] array, long length)` Grows the given big array to the maximum between the given length and the current length divided by the golden ratio, provided that the given length is larger than the current length.
`static double[][]`	`grow(double[][] array, long length, long preserve)` Grows the given big array to the maximum between the given length and the current length divided by the golden ratio, provided that the given length is larger than the current length, preserving just a part of the big array.
`static void`	`incr(double[][] array, long index)` Increments the element of the given big array of specified index.
`static long`	`length(double[][] array)` Returns the length of the given big array.
`static void`	`mul(double[][] array, long index, double factor)` Multiplies by the specified factor the element of the given big array of specified index.
`static double[][]`	`newBigArray(long length)` Creates a new big array.
`static void`	`quickSort(double[][] x)` Sorts the specified big array according to the natural ascending order using quicksort.
`static void`	`quickSort(double[][] x, DoubleComparator comp)` Sorts the specified big array according to the order induced by the specified comparator using quicksort.
`static void`	`quickSort(double[][] x, long from, long to)` Sorts the specified range of elements according to the natural ascending order using quicksort.
`static void`	`quickSort(double[][] x, long from, long to, DoubleComparator comp)` Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.
`static void`	`set(double[][] array, long index, double value)` Sets the element of the given big array of specified index.
`static double[][]`	`setLength(double[][] array, long length)` Sets the length of the given big array.
`static double[][]`	`shuffle(double[][] a, long from, long to, Random random)` Shuffles the specified big array fragment using the specified pseudorandom number generator.
`static double[][]`	`shuffle(double[][] a, Random random)` Shuffles the specified big array using the specified pseudorandom number generator.
`static void`	`swap(double[][] array, long first, long second)` Swaps the element of the given big array of specified indices.
`static String`	`toString(double[][] a)`
`static double[][]`	`trim(double[][] array, long length)` Trims the given big array to the given length.
`static double[][]`	`wrap(double[] array)` Turns a standard array into a big array.

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

- Field Detail
  - ONEOVERPHI
```
public static final long ONEOVERPHI
```
    The inverse of the golden ratio times 2¹⁶.
    
    See Also:
    Constant Field Values
  - EMPTY_BIG_ARRAY
```
public static final double[][] EMPTY_BIG_ARRAY
```
    A static, final, empty big array.
  - HASH_STRATEGY
```
public static final Hash.Strategy HASH_STRATEGY
```
    A type-specific content-based hash strategy for big arrays.
    This hash strategy may be used in custom hash collections whenever keys are big arrays, and they must be considered equal by content. This strategy will handle null correctly, and it is serializable.
- Method Detail
  - get
```
public static double get(double[][] array,
         long index)
```
    Returns the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
    
    Returns:
    the element of the big array at the specified position.
  - set
```
public static void set(double[][] array,
       long index,
       double value)
```
    Sets the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
  - swap
```
public static void swap(double[][] array,
        long first,
        long second)
```
    Swaps the element of the given big array of specified indices.
    
    Parameters:
    array - a big array.
    first - a position in the big array.
    second - a position in the big array.
  - add
```
public static void add(double[][] array,
       long index,
       double incr)
```
    Adds the specified increment the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
    incr - the increment
  - mul
```
public static void mul(double[][] array,
       long index,
       double factor)
```
    Multiplies by the specified factor the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
    factor - the factor
  - incr
```
public static void incr(double[][] array,
        long index)
```
    Increments the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
  - decr
```
public static void decr(double[][] array,
        long index)
```
    Decrements the element of the given big array of specified index.
    
    Parameters:
    array - a big array.
    index - a position in the big array.
  - length
```
public static long length(double[][] array)
```
    Returns the length of the given big array.
    
    Parameters:
    array - a big array.
    
    Returns:
    the length of the given big array.
  - copy
```
public static void copy(double[][] srcArray,
        long srcPos,
        double[][] destArray,
        long destPos,
        long length)
```
    Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination big array. Handles correctly overlapping regions of the same big array.
    
    Parameters:
    srcArray - the source big array.
    srcPos - the starting position in the source big array.
    destArray - the destination big array.
    destPos - the starting position in the destination data.
    length - the number of elements to be copied.
  - copyFromBig
```
public static void copyFromBig(double[][] srcArray,
               long srcPos,
               double[] destArray,
               int destPos,
               int length)
```
    Copies a big array from the specified source big array, beginning at the specified position, to the specified position of the destination array.
    
    Parameters:
    srcArray - the source big array.
    srcPos - the starting position in the source big array.
    destArray - the destination array.
    destPos - the starting position in the destination data.
    length - the number of elements to be copied.
  - copyToBig
```
public static void copyToBig(double[] srcArray,
             int srcPos,
             double[][] destArray,
             long destPos,
             long length)
```
    Copies an array from the specified source array, beginning at the specified position, to the specified position of the destination big array.
    
    Parameters:
    srcArray - the source array.
    srcPos - the starting position in the source array.
    destArray - the destination big array.
    destPos - the starting position in the destination data.
    length - the number of elements to be copied.
  - newBigArray
```
public static double[][] newBigArray(long length)
```
    Creates a new big array.
    
    Parameters:
    length - the length of the new big array.
    
    Returns:
    a new big array of given length.
  - wrap
```
public static double[][] wrap(double[] array)
```
    Turns a standard array into a big array.
    Note that the returned big array might contain as a segment the original array.
    
    Parameters:
    array - an array.
    
    Returns:
    a new big array with the same length and content of array.
  - ensureCapacity
```
public static double[][] ensureCapacity(double[][] array,
                        long length)
```
    Ensures that a big array can contain the given number of entries.
    If you cannot foresee whether this big array will need again to be enlarged, you should probably use grow() instead.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new minimum length for this big array.
    
    Returns:
    array, if it contains length entries or more; otherwise, a big array with length entries whose first length(array) entries are the same as those of array.
  - ensureCapacity
```
public static double[][] ensureCapacity(double[][] array,
                        long length,
                        long preserve)
```
    Ensures that a big array can contain the given number of entries, preserving just a part of the big array.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new minimum length for this big array.
    preserve - the number of elements of the big array that must be preserved in case a new allocation is necessary.
    
    Returns:
    array, if it can contain length entries or more; otherwise, a big array with length entries whose first preserve entries are the same as those of array.
  - grow
```
public static double[][] grow(double[][] array,
              long length)
```
    Grows the given big array to the maximum between the given length and the current length divided by the golden ratio, provided that the given length is larger than the current length.
    Dividing by the golden ratio (φ) approximately increases the big array length by 1.618. If you want complete control on the big array growth, you should probably use ensureCapacity() instead.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new minimum length for this big array.
    
    Returns:
    array, if it can contain length entries; otherwise, a big array with max(length,length(array)/φ) entries whose first length(array) entries are the same as those of array.
  - grow
```
public static double[][] grow(double[][] array,
              long length,
              long preserve)
```
    Grows the given big array to the maximum between the given length and the current length divided by the golden ratio, provided that the given length is larger than the current length, preserving just a part of the big array.
    Dividing by the golden ratio (φ) approximately increases the big array length by 1.618. If you want complete control on the big array growth, you should probably use ensureCapacity() instead.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new minimum length for this big array.
    preserve - the number of elements of the big array that must be preserved in case a new allocation is necessary.
    
    Returns:
    array, if it can contain length entries; otherwise, a big array with max(length,length(array)/φ) entries whose first preserve entries are the same as those of array.
  - trim
```
public static double[][] trim(double[][] array,
              long length)
```
    Trims the given big array to the given length.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new maximum length for the big array.
    
    Returns:
    array, if it contains length entries or less; otherwise, a big array with length entries whose entries are the same as the first length entries of array.
  - setLength
```
public static double[][] setLength(double[][] array,
                   long length)
```
    Sets the length of the given big array.
    Warning: the returned array might use part of the segments of the original array, which must be considered read-only after calling this method.
    
    Parameters:
    array - a big array.
    length - the new length for the big array.
    
    Returns:
    array, if it contains exactly length entries; otherwise, if it contains more than length entries, a big array with length entries whose entries are the same as the first length entries of array; otherwise, a big array with length entries whose first length(array) entries are the same as those of array.
  - copy
```
public static double[][] copy(double[][] array,
              long offset,
              long length)
```
    Returns a copy of a portion of a big array.
    
    Parameters:
    array - a big array.
    offset - the first element to copy.
    length - the number of elements to copy.
    
    Returns:
    a new big array containing length elements of array starting at offset.
  - copy
```
public static double[][] copy(double[][] array)
```
    Returns a copy of a big array.
    
    Parameters:
    array - a big array.
    
    Returns:
    a copy of array.
  - fill
```
public static void fill(double[][] array,
        double value)
```
    Fills the given big array with the given value.
    This method uses a backward loop. It is significantly faster than the corresponding method in Arrays.
    
    Parameters:
    array - a big array.
    value - the new value for all elements of the big array.
  - fill
```
public static void fill(double[][] array,
        long from,
        long to,
        double value)
```
    Fills a portion of the given big array with the given value.
    If possible (i.e., from is 0) this method uses a backward loop. In this case, it is significantly faster than the corresponding method in Arrays.
    
    Parameters:
    array - a big array.
    from - the starting index of the portion to fill.
    to - the end index of the portion to fill.
    value - the new value for all elements of the specified portion of the big array.
  - equals
```
public static boolean equals(double[][] a1,
             double[][] a2)
```
    Returns true if the two big arrays are elementwise equal.
    This method uses a backward loop. It is significantly faster than the corresponding method in Arrays.
    
    Parameters:
    a1 - a big array.
    a2 - another big array.
    
    Returns:
    true if the two big arrays are of the same length, and their elements are equal.
  - toString
```
public static String toString(double[][] a)
```
  - ensureFromTo
```
public static void ensureFromTo(double[][] a,
                long from,
                long to)
```
    Ensures that a range given by its first (inclusive) and last (exclusive) elements fits a big array.
    This method may be used whenever a big array range check is needed.
    
    Parameters:
    a - a big array.
    from - a start index (inclusive).
    to - an end index (inclusive).
    
    Throws:
    
    IllegalArgumentException - if from is greater than to.
    
    ArrayIndexOutOfBoundsException - if from or to are greater than the big array length or negative.
  - ensureOffsetLength
```
public static void ensureOffsetLength(double[][] a,
                      long offset,
                      long length)
```
    Ensures that a range given by an offset and a length fits a big array.
    This method may be used whenever a big array range check is needed.
    
    Parameters:
    a - a big array.
    offset - a start index.
    length - a length (the number of elements in the range).
    
    Throws:
    
    IllegalArgumentException - if length is negative.
    
    ArrayIndexOutOfBoundsException - if offset is negative or offset+length is greater than the big array length.
  - quickSort
```
public static void quickSort(double[][] x,
             long from,
             long to,
             DoubleComparator comp)
```
    Sorts the specified range of elements according to the order induced by the specified comparator using quicksort.
    The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
    
    Parameters:
    x - the big array to be sorted.
    from - the index of the first element (inclusive) to be sorted.
    to - the index of the last element (exclusive) to be sorted.
    comp - the comparator to determine the sorting order.
  - quickSort
```
public static void quickSort(double[][] x,
             DoubleComparator comp)
```
    Sorts the specified big array according to the order induced by the specified comparator using quicksort.
    The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
    
    Parameters:
    x - the big array to be sorted.
    comp - the comparator to determine the sorting order.
  - quickSort
```
public static void quickSort(double[][] x,
             long from,
             long to)
```
    Sorts the specified range of elements according to the natural ascending order using quicksort.
    The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
    
    Parameters:
    x - the big array to be sorted.
    from - the index of the first element (inclusive) to be sorted.
    to - the index of the last element (exclusive) to be sorted.
  - quickSort
```
public static void quickSort(double[][] x)
```
    Sorts the specified big array according to the natural ascending order using quicksort.
    The sorting algorithm is a tuned quicksort adapted from Jon L. Bentley and M. Douglas McIlroy, “Engineering a Sort Function”, Software: Practice and Experience, 23(11), pages 1249−1265, 1993.
    
    Parameters:
    x - the big array to be sorted.
  - binarySearch
```
public static long binarySearch(double[][] a,
                long from,
                long to,
                double key)
```
    Searches a range of the specified big array for the specified value using the binary search algorithm. The range must be sorted prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
    
    Parameters:
    a - the big array to be searched.
    from - the index of the first element (inclusive) to be searched.
    to - the index of the last element (exclusive) to be searched.
    key - the value to be searched for.
    
    Returns:
    index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
    See Also:
    Arrays
  - binarySearch
```
public static long binarySearch(double[][] a,
                double key)
```
    Searches a big array for the specified value using the binary search algorithm. The range must be sorted prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
    
    Parameters:
    a - the big array to be searched.
    key - the value to be searched for.
    
    Returns:
    index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
    See Also:
    Arrays
  - binarySearch
```
public static long binarySearch(double[][] a,
                long from,
                long to,
                double key,
                DoubleComparator c)
```
    Searches a range of the specified big array for the specified value using the binary search algorithm and a specified comparator. The range must be sorted following the comparator prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
    
    Parameters:
    a - the big array to be searched.
    from - the index of the first element (inclusive) to be searched.
    to - the index of the last element (exclusive) to be searched.
    key - the value to be searched for.
    c - a comparator.
    
    Returns:
    index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
    See Also:
    Arrays
  - binarySearch
```
public static long binarySearch(double[][] a,
                double key,
                DoubleComparator c)
```
    Searches a big array for the specified value using the binary search algorithm and a specified comparator. The range must be sorted following the comparator prior to making this call. If it is not sorted, the results are undefined. If the range contains multiple elements with the specified value, there is no guarantee which one will be found.
    
    Parameters:
    a - the big array to be searched.
    key - the value to be searched for.
    c - a comparator.
    
    Returns:
    index of the search key, if it is contained in the big array; otherwise, (-(insertion point) - 1). The insertion point is defined as the the point at which the value would be inserted into the big array: the index of the first element greater than the key, or the length of the big array, if all elements in the big array are less than the specified key. Note that this guarantees that the return value will be >= 0 if and only if the key is found.
    See Also:
    Arrays
  - shuffle
```
public static double[][] shuffle(double[][] a,
                 long from,
                 long to,
                 Random random)
```
    Shuffles the specified big array fragment using the specified pseudorandom number generator.
    
    Parameters:
    a - the big array to be shuffled.
    from - the index of the first element (inclusive) to be shuffled.
    to - the index of the last element (exclusive) to be shuffled.
    random - a pseudorandom number generator (please use a XorShift* generator).
    
    Returns:
    a.
  - shuffle
```
public static double[][] shuffle(double[][] a,
                 Random random)
```
    Shuffles the specified big array using the specified pseudorandom number generator.
    
    Parameters:
    a - the big array to be shuffled.
    random - a pseudorandom number generator (please use a XorShift* generator).
    
    Returns:
    a.

Class DoubleBigArrays

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ONEOVERPHI

EMPTY_BIG_ARRAY

HASH_STRATEGY

Method Detail

get

set

swap

add

mul

incr

decr

length

copy

copyFromBig

copyToBig

newBigArray

wrap

ensureCapacity

ensureCapacity

grow

grow

trim

setLength

copy

copy

fill

fill

equals

toString

ensureFromTo

ensureOffsetLength

quickSort

quickSort

quickSort

quickSort

binarySearch

binarySearch

binarySearch

binarySearch

shuffle

shuffle