On Sat, Nov 20, 2010 at 8:58 PM, Lance Norskog <[email protected]> wrote:
> To explain that better, with an example: > > public Matrix Matrix.times(Matrix input); > > The standard implementation uses this.like() to create an output > matrix and populates it. If the input matrix is sparse, the output > should have the same sparse implementation because X times 0 = 0. So, > RandomVector and RandomMatrix should use input.like() in this case. > > On Sat, Nov 20, 2010 at 8:49 PM, Lance Norskog <[email protected]> wrote: > > Ok. The use case is read-only random Vector & Matrix classes. They > > return the same value for each position. They take no space. > > Matrix.like() could make whatever you want: Dense, Sparse, whatever. > > > > https://issues.apache.org/jira/browse/MAHOUT-550 > > > > Please have a look and tell me if this is on the right track. > > > > On Fri, Nov 19, 2010 at 8:44 AM, Jeff Eastman <[email protected]> > wrote: > >> +1 Seems sensible to me too > >> > >> -----Original Message----- > >> From: Ted Dunning [mailto:[email protected]] > >> Sent: Friday, November 19, 2010 8:12 AM > >> To: [email protected] > >> Subject: Re: Matrix and Vector classes: Read-only semantics > >> > >> What it really means is fail or return something sensible. I think your > >> interpretation > >> is pretty sensible. > >> > >> On Fri, Nov 19, 2010 at 1:28 AM, Lance Norskog <[email protected]> > wrote: > >> > >>> Here's the problem: "empty" means writable. A read-only class cannot > >>> do this. I think the semantics meant are: "return a writable Vector > >>> with the same dense/sparse styleas this Vector": a dense read-only > >>> vector class would create a DenseVector, for example. > >>> > >>> Yes? No? > >>> > >> > > > > > > > > -- > > Lance Norskog > > [email protected] > > > > > > -- > Lance Norskog > [email protected] >
