程序包 weka.core.matrix

类 LUDecomposition

java.lang.Object
weka.core.matrix.LUDecomposition
所有已实现的接口:
Serializable, RevisionHandler

public class LUDecomposition extends Object implements Serializable, RevisionHandler
LU Decomposition.

For an m-by-n matrix A with m >= n, the LU decomposition is an m-by-n unit lower triangular matrix L, an n-by-n upper triangular matrix U, and a permutation vector piv of length m so that A(piv,:) = L*U. If m < n, then L is m-by-m and U is m-by-n.

The LU decompostion with pivoting always exists, even if the matrix is singular, so the constructor will never fail. The primary use of the LU decomposition is in the solution of square systems of simultaneous linear equations. This will fail if isNonsingular() returns false.

Adapted from the JAMA package.

版本:
$Revision: 1.4 $
作者:
The Mathworks and NIST, Fracpete (fracpete at waikato dot ac dot nz)
另请参阅:
  • 构造器详细资料

    • LUDecomposition

      public LUDecomposition(Matrix A)
      LU Decomposition
      参数:
      A - Rectangular matrix
  • 方法详细资料

    • isNonsingular

      public boolean isNonsingular()
      Is the matrix nonsingular?
      返回:
      true if U, and hence A, is nonsingular.
    • getL

      public Matrix getL()
      Return lower triangular factor
      返回:
      L
    • getU

      public Matrix getU()
      Return upper triangular factor
      返回:
      U
    • getPivot

      public int[] getPivot()
      Return pivot permutation vector
      返回:
      piv
    • getDoublePivot

      public double[] getDoublePivot()
      Return pivot permutation vector as a one-dimensional double array
      返回:
      (double) piv
    • det

      public double det()
      Determinant
      返回:
      det(A)
      抛出:
      IllegalArgumentException - Matrix must be square
    • solve

      public Matrix solve(Matrix B)
      Solve A*X = B
      参数:
      B - A Matrix with as many rows as A and any number of columns.
      返回:
      X so that L*U*X = B(piv,:)
      抛出:
      IllegalArgumentException - Matrix row dimensions must agree.
      RuntimeException - Matrix is singular.
    • getRevision

      public String getRevision()
      Returns the revision string.
      指定者:
      getRevision 在接口中 RevisionHandler
      返回:
      the revision