Package org.apfloat.internal
Class IntKaratsubaConvolutionStrategy
- java.lang.Object
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- org.apfloat.internal.IntBaseMath
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- org.apfloat.internal.IntMediumConvolutionStrategy
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- org.apfloat.internal.IntKaratsubaConvolutionStrategy
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- All Implemented Interfaces:
Serializable
,ConvolutionStrategy
public class IntKaratsubaConvolutionStrategy extends IntMediumConvolutionStrategy
Convolution strategy using the Karatsuba algorithm. The complexity of the algorithm is O(nlog(3)/log(2)) as the operands are split to two and multiplied using three multiplications (and five additions / subtractions). This splitting is done recursively until some cut-off point where the basic O(n2) algorithm is applied. The Karatsuba algorithm is faster than the basic O(n2) multiplication algorithm for medium size numbers larger than some certain size. For very large numbers, the transform-based convolution algorithms are faster.- Since:
- 1.4
- Version:
- 1.4
- Author:
- Mikko Tommila
- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static int
CUTOFF_POINT
Cut-off point for Karatsuba / basic convolution.
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Constructor Summary
Constructors Constructor Description IntKaratsubaConvolutionStrategy(int radix)
Creates a convolution strategy using the specified radix.
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Method Summary
Modifier and Type Method Description DataStorage
convolute(DataStorage x, DataStorage y, long resultSize)
Convolutes the two sets of data.-
Methods inherited from class org.apfloat.internal.IntBaseMath
baseAdd, baseDivide, baseMultiplyAdd, baseSubtract
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Field Detail
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CUTOFF_POINT
public static final int CUTOFF_POINT
Cut-off point for Karatsuba / basic convolution.Convolutions where the shorter number is at most this long are calculated using the basic O(n2) algorithm i.e.
super.convolute()
.- See Also:
- Constant Field Values
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Method Detail
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convolute
public DataStorage convolute(DataStorage x, DataStorage y, long resultSize) throws ApfloatRuntimeException
Description copied from interface:ConvolutionStrategy
Convolutes the two sets of data.- Specified by:
convolute
in interfaceConvolutionStrategy
- Overrides:
convolute
in classIntMediumConvolutionStrategy
- Parameters:
x
- First data set.y
- Second data set.resultSize
- Number of elements needed in the result data.- Returns:
- The convolved data.
- Throws:
ApfloatRuntimeException
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