Package org.jblas.util
Class Permutations
- java.lang.Object
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- org.jblas.util.Permutations
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public class Permutations extends java.lang.Object
Functions which generate random permutations.- Author:
- Mikio L. Braun
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Constructor Summary
Constructors Constructor Description Permutations()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static DoubleMatrix
permutationDoubleMatrixFromPivotIndices(int size, int[] ipiv)
Create a permutation matrix from a LAPACK-style 'ipiv' vector.static FloatMatrix
permutationFloatMatrixFromPivotIndices(int size, int[] ipiv)
Create a permutation matrix from a LAPACK-style 'ipiv' vector.static int[]
randomPermutation(int size)
Create a random permutation of the numbers 0, ..., size - 1.static int[]
randomSubset(int k, int n)
Get a random sample of k out of n elements.
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Constructor Detail
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Permutations
public Permutations()
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Method Detail
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randomPermutation
public static int[] randomPermutation(int size)
Create a random permutation of the numbers 0, ..., size - 1. see Algorithm P, D.E. Knuth: The Art of Computer Programming, Vol. 2, p. 145
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randomSubset
public static int[] randomSubset(int k, int n)
Get a random sample of k out of n elements. See Algorithm S, D. E. Knuth, The Art of Computer Programming, Vol. 2, p.142.
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permutationDoubleMatrixFromPivotIndices
public static DoubleMatrix permutationDoubleMatrixFromPivotIndices(int size, int[] ipiv)
Create a permutation matrix from a LAPACK-style 'ipiv' vector.- Parameters:
ipiv
- row i was interchanged with row ipiv[i]
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permutationFloatMatrixFromPivotIndices
public static FloatMatrix permutationFloatMatrixFromPivotIndices(int size, int[] ipiv)
Create a permutation matrix from a LAPACK-style 'ipiv' vector.- Parameters:
ipiv
- row i was interchanged with row ipiv[i]
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