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## no.uib.cipr.matrix
Class BandCholesky

    java.lang.Object
      no.uib.cipr.matrix.BandCholesky

    public class BandCholesky

extends java.lang.Object

Banded Cholesky decomposition

Constructor Summary
`BandCholesky(int n, int kd, boolean upper)` Constructor for BandCholesky

Method Summary
`BandCholesky` | `factor(LowerSPDBandMatrix A)` Creates a Cholesky decomposition of the given matrix
`BandCholesky` | `factor(UpperSPDBandMatrix A)` Creates a Cholesky decomposition of the given matrix
`static BandCholesky` | `factorize(LowerSPDBandMatrix A)` Creates a Cholesky decomposition of the given matrix
`static BandCholesky` | `factorize(UpperSPDBandMatrix A)` Creates a Cholesky decomposition of the given matrix
`LowerTriangBandMatrix` | `getL()` Returns the decomposition matrix.
`UpperTriangBandMatrix` | `getU()` Returns the decomposition matrix.
`boolean` | `isSPD()` Returns true if the matrix decomposed is symmetrical, positive definite
`double` | `rcond(Matrix A)` Computes the reciprocal condition number
`DenseMatrix` | `solve(DenseMatrix B)` Computes `A\B`, overwriting `B`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### BandCholesky

    public BandCholesky(int n,
                        int kd,
                        boolean upper)

  Constructor for BandCholesky

  Parameters:
    `n` - Matrix size
    `kd` - Number of matrix bands
    `upper` - True for decomposing an upper symmetrical matrix, false for a lower symmetrical matrix

Method Detail

### factorize

    public static BandCholesky factorize(LowerSPDBandMatrix A)

  Creates a Cholesky decomposition of the given matrix

  Parameters:
    `A` - Matrix to decompose. Not modified
  Returns:
    A Cholesky decomposition of the matrix

### factorize

    public static BandCholesky factorize(UpperSPDBandMatrix A)

  Creates a Cholesky decomposition of the given matrix

  Parameters:
    `A` - Matrix to decompose. Not modified
  Returns:
    A Cholesky decomposition of the matrix

### factor

    public BandCholesky factor(LowerSPDBandMatrix A)

  Creates a Cholesky decomposition of the given matrix

  Parameters:
    `A` - Matrix to decompose. Overwritten on return
  Returns:
    The current decomposition

### factor

    public BandCholesky factor(UpperSPDBandMatrix A)

  Creates a Cholesky decomposition of the given matrix

  Parameters:
    `A` - Matrix to decompose. Overwritten on return
  Returns:
    The current decomposition

### getL

    public LowerTriangBandMatrix getL()

  Returns the decomposition matrix. Only valid for decomposition of a lower SPD matrix

### getU

    public UpperTriangBandMatrix getU()

  Returns the decomposition matrix. Only valid for decomposition of a upper SPD matrix

### isSPD

    public boolean isSPD()

  Returns true if the matrix decomposed is symmetrical, positive definite

### rcond

    public double rcond(Matrix A)

  Computes the reciprocal condition number

  Parameters:
    `A` - The matrix this is a decomposition of
  Returns:
    The reciprocal condition number. Values close to unity indicate a well-conditioned system, while numbers close to zero do not.

### solve

    public DenseMatrix solve(DenseMatrix B)
                      throws MatrixNotSPDException

  Computes `A\B`, overwriting `B`

  Throws:
    `MatrixNotSPDException`

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