sparse triplet to sparse matrix matlab

Question

What command can I use to convert a sparse triplet into a sparse matrix in MATLAB? I've been trying this one: B=st_to_msm(A) , where A is my sparse triplet read from a ".dat" file, and B is just some variable.

It's not working for me, though. I want to know how to fix it or if there's another command to do the conversion.

Answer 1

MATLAB has only 2D sparse matrices and thus 3D addressing won't work for sparse matrices.

You may want to check N-dimensional sparse arrays in MATLAB Central File Exchange .

Answer 2

The code for st_to_msm is http://people.sc.fsu.edu/~jburkardt/m_src/st_to_msm/st_to_msm.m

  [ nrow, ncol, nnzero ] = st_header_read ( input_file );
  [ row, col, a ] = st_data_read ( input_file, nrow, ncol, nnzero );

  base0 = 0;
  base1 = 1;
  row = st_rebase ( base0, base1, nnzero, row );
  col = st_rebase ( base0, base1, nnzero, col );
  b = sparse ( row, col, a, nrow, ncol, nnzero );

In other words, it reads dimensions, and 3 vectors from the file, and uses them as arguments to the sparse function. I suspect your A consists of those 3 vectors, row , col , a . Look at the documentation for sparse for more details.