public class QrHelperFunctions_DSCC
extends java.lang.Object
Constructor and Description |
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QrHelperFunctions_DSCC() |
Modifier and Type | Method and Description |
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static void |
applyHouseholder(org.ejml.data.DMatrixSparseCSC V,
int colV,
double beta,
double[] x)
Applies a sparse Householder vector to a dense vector.
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static double |
computeHouseholder(double[] x,
int xStart,
int xEnd,
double max,
org.ejml.data.DScalar gamma)
Creates a householder reflection.
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static void |
rank1UpdateMultR(org.ejml.data.DMatrixSparseCSC V,
int colV,
double gamma,
org.ejml.data.DMatrixSparseCSC A,
org.ejml.data.DMatrixSparseCSC C,
org.ejml.data.IGrowArray gw,
org.ejml.data.DGrowArray gx)
Performs a rank-1 update operation on the submatrix specified by V with the multiply on the right.
C = (I - γ*v*vT)*A |
public static void applyHouseholder(org.ejml.data.DMatrixSparseCSC V, int colV, double beta, double[] x)
Applies a sparse Householder vector to a dense vector.
x = x - v*(beta*(v'*x))
NOTE: This is the same as cs_happly() in csparse
V
- (Input) Matrix containing the HouseholdercolV
- Column in V with the Householder vectorbeta
- scalarx
- (Input and Output) vector that the Householder is applied to. Modified.public static void rank1UpdateMultR(org.ejml.data.DMatrixSparseCSC V, int colV, double gamma, org.ejml.data.DMatrixSparseCSC A, org.ejml.data.DMatrixSparseCSC C, org.ejml.data.IGrowArray gw, org.ejml.data.DGrowArray gx)
Performs a rank-1 update operation on the submatrix specified by V with the multiply on the right.
C = (I - γ*v*vT)*A
The order that matrix multiplies are performed has been carefully selected to minimize the number of operations.
Before this can become a truly generic operation the submatrix specification needs to be made more generic.
public static double computeHouseholder(double[] x, int xStart, int xEnd, double max, org.ejml.data.DScalar gamma)
NOTE: Same as cs_house in csparse
x
- (Input) Vector x (Output) Vector v. Modified.xStart
- First index in X that is to be processedxEnd
- Last + 1 index in x that is to be processed.gamma
- (Output) Storage for computed gamma