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java.lang.Objectorg.apache.commons.math3.linear.RealLinearOperator
public abstract class RealLinearOperator
This class defines a linear operator operating on real (double)
vector spaces. No direct access to the coefficients of the underlying matrix
is provided.
The motivation for such an interface is well stated by
Barrett et al. (1994):
We restrict ourselves to iterative methods, which work by repeatedly improving an approximate solution until it is accurate enough. These methods access the coefficient matrix A of the linear system only via the matrix-vector product y = A · x (and perhaps z = AT · x). Thus the user need only supply a subroutine for computing y (and perhaps z) given x, which permits full exploitation of the sparsity or other special structure of A.
| Constructor Summary | |
|---|---|
RealLinearOperator()
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| Method Summary | |
|---|---|
abstract int |
getColumnDimension()
Returns the dimension of the domain of this operator. |
abstract int |
getRowDimension()
Returns the dimension of the codomain of this operator. |
boolean |
isTransposable()
Returns true if this operator supports
operateTranspose(RealVector). |
abstract RealVector |
operate(RealVector x)
Returns the result of multiplying this by the vector x. |
RealVector |
operateTranspose(RealVector x)
Returns the result of multiplying the transpose of this operator
by the vector x (optional operation). |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
public RealLinearOperator()
| Method Detail |
|---|
public abstract int getRowDimension()
public abstract int getColumnDimension()
public abstract RealVector operate(RealVector x)
throws DimensionMismatchException
this by the vector x.
x - the vector to operate on
this instance with x
DimensionMismatchException - if the column dimension does not match
the size of x
public RealVector operateTranspose(RealVector x)
throws DimensionMismatchException,
UnsupportedOperationException
this operator
by the vector x (optional operation). The default implementation
throws an UnsupportedOperationException. Users overriding this
method must also override isTransposable().
x - the vector to operate on
this instance with
x
DimensionMismatchException - if the row dimension does not match the size of x
UnsupportedOperationException - if this operation is not supported
by this operatorpublic boolean isTransposable()
true if this operator supports
operateTranspose(RealVector). If true is returned,
operateTranspose(RealVector) should not throw
UnsupportedOperationException. The default implementation returns
false.
false
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