org.apfloat.internal
Class LongCarryCRT

java.lang.Object
  extended by org.apfloat.internal.LongBaseMath
      extended by org.apfloat.internal.LongCRTMath
          extended by org.apfloat.internal.LongCarryCRT
All Implemented Interfaces:
Serializable

public class LongCarryCRT
extends LongCRTMath

Class for performing the final step of a three-modulus Number Theoretic Transform based convolution. Works for the long type.

The algorithm is parallelized for multiprocessor computers, if the data fits in memory.

The parallelization works so that the carry-CRT is done in blocks in parallel. As a final step, a second pass is done through the data set to propagate the carries from one block to the next.

Version:
1.6.1
Author:
Mikko Tommila
See Also:
Serialized Form

Constructor Summary
LongCarryCRT(int radix)
          Creates a carry-CRT object using the specified radix.
 
Method Summary
 DataStorage carryCRT(DataStorage resultMod0, DataStorage resultMod1, DataStorage resultMod2, long resultSize)
          Calculate the final result of a three-NTT convolution.
 void setParallelRunner(ParallelRunner parallelRunner)
          Set the parallel runner to be used when executing the CRT.
 
Methods inherited from class org.apfloat.internal.LongCRTMath
add, compare, divide, multiply, subtract
 
Methods inherited from class org.apfloat.internal.LongBaseMath
baseAdd, baseDivide, baseMultiplyAdd, baseSubtract
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

LongCarryCRT

public LongCarryCRT(int radix)
Creates a carry-CRT object using the specified radix.

Parameters:
radix - The radix that will be used.
Method Detail

carryCRT

public DataStorage carryCRT(DataStorage resultMod0,
                            DataStorage resultMod1,
                            DataStorage resultMod2,
                            long resultSize)
                     throws ApfloatRuntimeException
Calculate the final result of a three-NTT convolution.

Performs a Chinese Remainder Theorem (CRT) on each element of the three result data sets to get the result of each element modulo the product of the three moduli. Then it calculates the carries to get the final result.

Note that the return value's initial word may be zero or non-zero, depending on how large the result is.

Assumes that MODULUS[0] > MODULUS[1] > MODULUS[2].

Parameters:
resultMod0 - The result modulo MODULUS[0].
resultMod1 - The result modulo MODULUS[1].
resultMod2 - The result modulo MODULUS[2].
resultSize - The number of elements needed in the final result.
Returns:
The final result with the CRT performed and the carries calculated.
Throws:
ApfloatRuntimeException

setParallelRunner

public void setParallelRunner(ParallelRunner parallelRunner)
Set the parallel runner to be used when executing the CRT.

Parameters:
parallelRunner - The parallel runner.