Happy 14th of July to all!
OK, from what I understand, the patch I submitted yesterday does not
comply with your requirements, as I provided a constructor for
RealLinearOperator, with dimensions of the domain and codomain as
parameters. Implicitely, I intended these to be fixed for the whole life
of the object. So, attached to JIRA MATH-581 is patch #05, with
following changes
- getRowDimension() and getColumnDimension() are now abstract
- constructor has been removed.
I think this is faithful to what I understood from the discussion.
However, I have now a question on the whole design, as I do not want to
do the same errors twice. I initially submitted RealLinearOperator as an
interface, but it was required to get rid of it, to the benefit of
abstract classes. That's fine, but the abstract class now does next to
nothing. My implementation of
double[] operate(double[])
based on
RealVector operate(RealVector)
is really for lazy people who can't be bothered when extending
RealLinearOperator. But we could have done without this default
implementation. We would then have had an empty abstract class. So why
not an interface? As I said, I want to learn, not to be controversial.
Also, I'd like to apologize for these multiple corrections of an albeit
simple set of classes. I hope I didn't waste to much of your time.
Sebastien
Le 14/07/11 00:01, Ted Dunning a écrit :
Actually, this is a major issue.
Take, for instance, the example of considering a Lucene index as a linear
operator. The number of rows is the number of documents (which is changing
as documents are added) and the number of columns is the number of unique
terms (which is also changing as documents are added).
Matrix multiplication consists of translating a (hopefully sparse) vector
into a query, running the query and interpreting the result as a (sparse)
vector.
This is just one of a host of similar application oriented definitions of a
LinearOperator, none of which define the number of rows and columns at
construction time.
I can still do a singular value decomposition of this linear operator
On Wed, Jul 13, 2011 at 1:52 PM, Phil Steitz<phil.ste...@gmail.com> wrote:
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