Thanks Sean! Let me take a look! Iman On Nov 8, 2016 7:29 AM, "Sean Owen" wrote: > I think the problem here is that IndexedRowMatrix.toRowMatrix does *not* > result in a RowMatrix with rows in order of their indices, necessarily: > > // Drop its row indices. > RowMatrix rowMat = indexedRowMatrix.toRowMatrix(); > > What you get is a matrix where the rows are arranged in whatever order > they were passed to IndexedRowMatrix. RowMatrix says it's for rows where > the ordering doesn't matter, but then it's maybe surprising it has a QR > decomposition method, because clearly the result depends on the order of > rows in the input. (CC Yuhao Yang for a comment?) > > You could say, well, why doesn't IndexedRowMatrix.toRowMatrix return at > least something with sorted rows? that would not be hard. It also won't > return "missing" rows (all zeroes), so it would not in any event result in > a RowMatrix whose implicit rows and ordering represented the same matrix. > That, at least, strikes me as something to be better documented. > > Maybe it would be nicer still to at least sort the rows, given the > existence of use cases like yours. For example, at least CoordinateMatrix.toIndexedRowMatrix > could sort? that is less surprising. > > In any event you should be able to make it work by manually getting the > RDD[IndexedRow] out of IndexedRowMatrix, sorting by index, then mapping it > to Vectors and making a RowMatrix from it. > > > > On Tue, Nov 8, 2016 at 2:41 PM Iman Mohtashemi > wrote: > >> Hi Sean, >> Here you go: >> >> sparsematrix.txt = >> >> row, col ,val >> 0,0,.42 >> 0,1,.28 >> 0,2,.89 >> 1,0,.83 >> 1,1,.34 >> 1,2,.42 >> 2,0,.23 >> 3,0,.42 >> 3,1,.98 >> 3,2,.88 >> 4,0,.23 >> 4,1,.36 >> 4,2,.97 >> >> The vector is just the third column of the matrix which should give the >> trivial solution of [0,0,1] >> >> This translates to this which is correct >> There are zeros in the matrix (Not really sparse but just an example) >> 0.42 0.28 0.89 >> 0.83 0.34 0.42 >> 0.23 0.0 0.0 >> 0.42 0.98 0.88 >> 0.23 0.36 0.97 >> >> >> Here is what I get for the Q and R >> >> Q: -0.21470961288429483 0.23590615093828807 0.6784910613691661 >> -0.3920784235278427 -0.06171221388256143 0.5847874866876442 >> -0.7748216464954987 -0.4003560542230838 -0.29392323671555354 >> -0.3920784235278427 0.8517909521421976 -0.31435038559403217 >> -0.21470961288429483 -0.23389547730301666 -0.11165321782745863 >> R: -1.0712142642814275 -0.8347536340918976 -1.227672225670157 >> 0.0 0.7662808691141717 0.7553315911660984 >> 0.0 0.0 0.7785210939368136 >> >> When running this in matlab the numbers are the same but row 1 is the >> last row and the last row is interchanged with row 3 >> >> >> >> On Mon, Nov 7, 2016 at 11:35 PM Sean Owen wrote: >> >> Rather than post a large section of code, please post a small example of >> the input matrix and its decomposition, to illustrate what you're saying is >> out of order. >> >> On Tue, Nov 8, 2016 at 3:50 AM im281 wrote: >> >> I am getting the correct rows but they are out of order. Is this a bug or >> am >> I doing something wrong? >> >> >>