SFT
Class SFTUtils

java.lang.Object
  SFT.SFTUtils

public class SFTUtils
extends java.lang.Object

Nested Class Summary

static class	SFTUtils.DiffFunction Class for calculating a difference function for two given functions f1, f2 s.t.
static class	SFTUtils.FullMapFunction class for creating a function from a given mapping of elements to their function values
static class	SFTUtils.ResultFunction class for creating a function from the results of the SFT algorithm.

Constructor Summary

SFTUtils()

Method Summary

static int[]	calcLogG(long[] G)
static int	calcLogN(long N)
static Complex	chi(int t, long[] G, long[] v, long[] y) calculate Chi over G
static Complex	chi(long N, long v, long y) calculate Chi over Z_N
static long[]	getVectorFromString(java.lang.String vector)
static java.lang.String	vectorToString(long[] elem)
static java.lang.String	vectorToString(java.lang.Long[] Elem)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SFTUtils

public SFTUtils()

Method Detail

vectorToString

public static java.lang.String vectorToString(long[] elem)

Parameters:

elem - vector to print in format (x1,...,xk)

Returns:

string representation of the vector

vectorToString

public static java.lang.String vectorToString(java.lang.Long[] Elem)

getVectorFromString

public static long[] getVectorFromString(java.lang.String vector)

Parameters:

vector - the string representation of a vector, as created by printVector

Returns:

the long array representing the vector

calcLogG

public static int[] calcLogG(long[] G)

Parameters:

G - an integer array describing the group Z_N1 X ... X Z_Nk

Returns:

an integer array of log_2(Ni), rounded up, for i in {1,...,k}

calcLogN

public static int calcLogN(long N)

Parameters:

N - describing Z_N

Returns:

log_2(N), rounded up

chi

public static Complex chi(int t,
                          long[] G,
                          long[] v,
                          long[] y)

calculate Chi over G

Parameters:

t - the size of the vector to look at for the calculation

G - vector of values describing G, i.e. Cartesian multiplication of Z_Ni

v - the vector of elements in G defining the chi function

y - input vector for the chi function

Returns:

chi_(v)[y] = chi_(alpha_1,...,alpha_k)[y_1,...,y_k]

chi

public static Complex chi(long N,
                          long v,
                          long y)

calculate Chi over Z_N

Parameters:

N - describing Z_N

v - the element in Z_N defining the chi function

y - input for the chi function

Returns:

chi_(v)[y]