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SSJ V. labo. |
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java.lang.Objectumontreal.iro.lecuyer.hups.PointSet
umontreal.iro.lecuyer.hups.CycleBasedPointSet
umontreal.iro.lecuyer.hups.CycleBasedPointSetBase2
umontreal.iro.lecuyer.hups.CycleBasedLFSR
public class CycleBasedLFSR
CycleBasedLFSR
LFSR generators produce numbers by generating a sequence of bits from a linear recurrence modulo 2, and forming fractional numbers by taking blocks of successive bits. More precisely, let F2 denote the finite field with two elements (say, 0 and 1). Let P(z) = zk - a1zk-1 - ... - ak be a polynomial with coefficients in F2, and consider the recurrence
whose characteristic polynomial is P(z). It should be understood that in all computations are performed in F2 (this can be identified with working in integer arithmetic modulo 2). Suppose that s0 = (x0,..., xk-1)∈{0, 1}k is fixed and define where s and L are positive integers. If P is primitive, s0Suppose now that we have J LFSR recurrences, the j-th one having a primitive characteristic polynomial Pj(z) of degree kj, and step size sj. Let {xj, n, n≥0} be the j-th LFSR sequence, and define xn = (x1, n + ... + xJ, n)mod 2 and un as in. Equivalently, if {uj, n, n≥0} is the output sequence from the j-th LFSR, then un = u1, n⊕ ... ⊕uJ, n where ⊕ denotes the bitwise exclusive-or in the binary expansion. The sequence {xn} is called the combined LFSR sequence and a generator that produces this {un} is called a combined LFSR generator.
Nested Class Summary |
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Nested classes/interfaces inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSetBase2 |
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CycleBasedPointSetBase2.CycleBasedPointSetBase2Iterator |
Nested classes/interfaces inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSet |
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CycleBasedPointSet.CycleBasedPointSetIterator |
Constructor Summary | |
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CycleBasedLFSR(int step1,
int nbcoeff1,
int[] nocoeff1)
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CycleBasedLFSR(int step1,
int step2,
int nbcoeff1,
int nbcoeff2,
int[] nocoeff1,
int[] nocoeff2)
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CycleBasedLFSR(String filename,
int no)
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Method Summary | |
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String |
toString()
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Methods inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSetBase2 |
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addRandomShift, clearRandomShift, formatPoints, getCoordinate, iterator |
Methods inherited from class umontreal.iro.lecuyer.hups.CycleBasedPointSet |
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getDimension |
Methods inherited from class umontreal.iro.lecuyer.hups.PointSet |
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addRandomShift, addRandomShift, addRandomShift, formatPoints, formatPoints, formatPoints, formatPointsBase, formatPointsBase, formatPointsBase, formatPointsBase, formatPointsNumbered, formatPointsNumbered, getNumPoints, getStream, randomize, randomize, randomize, randomize, randomize, setStream, unrandomize |
Methods inherited from class java.lang.Object |
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equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Constructor Detail |
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public CycleBasedLFSR(int step1, int nbcoeff1, int[] nocoeff1)
public CycleBasedLFSR(int step1, int step2, int nbcoeff1, int nbcoeff2, int[] nocoeff1, int[] nocoeff2)
public CycleBasedLFSR(String filename, int no)
Method Detail |
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public String toString()
PointSet
toString
in class CycleBasedPointSet
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SSJ V. labo. |
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