Thank you, Shirish. That makes sense. I'll update the docs to include this information.
Deron On Mon, Feb 15, 2016 at 4:26 PM, Shirish Tatikonda < shirish.tatiko...@gmail.com> wrote: > Both "mm" and "text" formats are identical except for a couple of > differences: > > 1) for "mm": the matrix metadata is included in the first two lines; and > for "text": the metadata is present in the associated .mtd file > 2) "mm" data must be in a single file (i.e., no *part* files) where "text" > data can span multiple *part* files (like any other file on HDFS). > > The support for "mm" is created mainly for the purpose of > importing/exporting data in the format that R likes. > > Shirish > > On Mon, Feb 15, 2016 at 4:17 PM, Deron Eriksson <deroneriks...@gmail.com> > wrote: > > > Hi, > > > > I have a question with regards to text vs mm. Isn't the mm coordinate > > format identical to the text format but the mm data file happens to > include > > the metadata line for rows, cols, and nnzs, so shouldn't they scale the > > same since the text row values (i,j,v) correspond to the mm rows? > > > > If we have the following MM: > > %%MatrixMarket matrix coordinate real general > > 4 3 6 > > 1 1 1.0 > > 1 2 2.0 > > 1 3 3.0 > > 3 1 7.0 > > 3 2 8.0 > > 3 3 9.0 > > > > The corresponding text format (with accompanying metadata file) is: > > 1 1 1.0 > > 1 2 2.0 > > 1 3 3.0 > > 3 1 7.0 > > 3 2 8.0 > > 3 3 9.0 > > > > So aren't these formats essentially the same? > > > > Deron > > > > > > On Mon, Feb 15, 2016 at 3:56 PM, Matthias Boehm <mbo...@us.ibm.com> > wrote: > > > > > The meta data file is still useful in order to get the format. In case > of > > > matrix market, errors will be raised if included meta data is > > inconsistent. > > > So no, we should not disallow to specify the meta data. In general, we > > > anyway recommend using text (textcell) instead mm (matrix market) for > > > scalability reasons. > > > > > > Regards, > > > Matthias > > > > > > [image: Inactive hide details for Deron Eriksson ---02/15/2016 03:45:46 > > > PM---Hi, The Matrix Market coordinate format contains # rows, #]Deron > > > Eriksson ---02/15/2016 03:45:46 PM---Hi, The Matrix Market coordinate > > > format contains # rows, # columns, and # > > > > > > From: Deron Eriksson <deroneriks...@gmail.com> > > > To: dev@systemml.incubator.apache.org > > > Date: 02/15/2016 03:45 PM > > > Subject: Matrix Market format with metadata file > > > ------------------------------ > > > > > > > > > > > > Hi, > > > > > > The Matrix Market coordinate format contains # rows, # columns, and # > > > non-zero values as metadata near the top of a matrix data file. > > > > > > If I write a matrix in mm format using SystemML, no metadata file is > > > created since the metadata is stored within the data file. > > > > > > However, when reading a matrix with mm format, I can supply a metadata > > > file, even though metadata exists in the matrix data file. Is there any > > > reason for this, or should this be disallowed since the metadata file > is > > > redundant and can cause confusion, since metadata values can then be > > > specified in two places, which then brings up the question, "which > > metadata > > > value should be used"? > > > > > > Deron > > > > > > > > > > > >
