Mercurial > octave-dspies
diff liboctave/Sparse.cc @ 8987:542015fada9e
Eliminate the workspace in sparse transpose.
The output's cidx (column start offset array) can serve as the
workspace, so the routines operate in the space of their output.
| author | Jason Riedy <jason@acm.org> |
|---|---|
| date | Mon, 16 Mar 2009 17:03:07 -0400 |
| parents | eb63fbe60fab |
| children | 39be2c4531c8 |
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--- a/liboctave/Sparse.cc Tue Mar 17 08:49:08 2009 +0100 +++ b/liboctave/Sparse.cc Mon Mar 16 17:03:07 2009 -0400 @@ -1062,28 +1062,28 @@ octave_idx_type nz = nnz (); Sparse<T> retval (nc, nr, nz); - OCTAVE_LOCAL_BUFFER (octave_idx_type, w, nr + 1); - for (octave_idx_type i = 0; i < nr; i++) - w[i] = 0; for (octave_idx_type i = 0; i < nz; i++) - w[ridx(i)]++; + retval.xcidx (ridx (i) + 1)++; + // retval.xcidx[1:nr] holds the row degrees for rows 0:(nr-1) nz = 0; - for (octave_idx_type i = 0; i < nr; i++) + for (octave_idx_type i = 1; i <= nr; i++) { - retval.xcidx(i) = nz; - nz += w[i]; - w[i] = retval.xcidx(i); + const octave_idx_type tmp = retval.xcidx (i); + retval.xcidx (i) = nz; + nz += tmp; } - retval.xcidx(nr) = nz; - w[nr] = nz; + // retval.xcidx[1:nr] holds row entry *start* offsets for rows 0:(nr-1) for (octave_idx_type j = 0; j < nc; j++) for (octave_idx_type k = cidx(j); k < cidx(j+1); k++) { - octave_idx_type q = w [ridx(k)]++; + octave_idx_type q = retval.xcidx (ridx (k) + 1)++; retval.xridx (q) = j; retval.xdata (q) = data (k); } + assert (nnz () == retval.xcidx (nr)); + // retval.xcidx[1:nr] holds row entry *end* offsets for rows 0:(nr-1) + // and retval.xcidx[0:(nr-1)] holds their row entry *start* offsets return retval; }