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Дата изменения: Tue Dec 28 20:59:06 2004
Дата индексирования: Sun Apr 10 00:14:58 2016
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ucar.multiarray
Interface IndexMap

All Known Implementing Classes:

ConcreteIndexMap

public interface IndexMap

This interface defines the services required by MultiArrayProxy to manipulate indexes and the dimensions of a MultiArray. There are two transformations represented. Each goes from int [] to int []. (The int values should actually be non-negative, as array indexes or array sizes.)

The transform most often used takes a MultiArrayProxy index and returns an index suitable for accessing the hidden 'backing' MultiArray. The int [] transform(int [] output, int [] input) does this. Refer to this as the forward transform. The setInput(int [] input) procedure binds the input array reference to the forward transformation. The transformation of values in the input array is obtained by calling int [] getTransformed(int [] output). Note that the reference to input is bound, not a copy. This allows changes in values of the input array to be reflected in subsequent calls to getTransformed with needing to call setInput again.

The other transform is used to determine the proxy shape. It takes the shape of the backing MultiArray as input. It goes in the opposite direction as the forward transform; refer to this as the reverse transform. (Note: it is not an inverse.) The setLengths(int [] lengths) is analogous to setInput() above. It is typically called once during MultiArrayProxy initialization. The function int [] getLengths(int [] output) is analogous to getTransformed. It is used to implement the proxy getLengths() method.

Method Summary

int[]	getLengths(int[] output) Reverse transform the lengths, placing the results in output.
int	getOutputLength() Return the length needed for an output vector.
int	getRank() Return the length of input vectors.
int[]	getTransformed(int[] output) Transform the current input, placing the results in output.
void	setInput(int[] input) Rebind the domain of getTransformed()
void	setLengths(int[] lengths) Initialize or reinitialize the IndexMap.
int[]	transform(int[] output, int[] input) Perform the forward transform.

Method Detail

getOutputLength

public int getOutputLength()

Return the length needed for an output vector. Will throw an exception if called before setInput().

setInput

public void setInput(int[] input)

Rebind the domain of getTransformed()

Parameters:

input - int array domain reference member.

getTransformed

public int[] getTransformed(int[] output)

Transform the current input, placing the results in output.

Parameters:

output - int array storage for the result. The elements of output are usually modified by this call.

Returns:

output

transform

public int[] transform(int[] output,
                       int[] input)

Perform the forward transform.

This function is equivalent to setInput(input); return getTransformed(output);

Parameters:

output - int array storage for the result. The elements of output are usually modified by this call.

input - int array which is the index to be transformed.

Returns:

output

getRank

public int getRank()

Return the length of input vectors. Will throw an exception if called before setLengths().

setLengths

public void setLengths(int[] lengths)

Initialize or reinitialize the IndexMap. Binds the domain of getLengths(), getRank().

Parameters:

lengths - int array representing the shape on the forward transform output.

getLengths

public int[] getLengths(int[] output)

Reverse transform the lengths, placing the results in output. Will throw an exception if called before setLengths().

Parameters:

output - int array storage for the result. The elements of output are usually modified by this call.

Returns:

output