How can I import a Harwell-Boeing matrix to matlab.

The problem with the matrix generated by Ansys is its definition, next you can see a part of the matrix:

Stiffness matrix from ANSYS FULL file dumped into Harwell-Boeing format

          351181          9562        166029        166029          9561
  RSA                     9561          9561        166029             0
  (I14)           (I14)           (d25.15)            (d25.15)            
  F                          1          9561
  1      0.133854120867834e+04
  28      0.899529610352173e+02
  54     -0.114678611765949e+02
  79      0.663666125908654e+02
  109     -0.498567094031801e+02
  138     -0.256735571427123e+03
  166     -0.158108238272616e+03
  178      0.791100342720065e+02
  189      0.950413624927081e+02
  199     -0.480044028990096e+03
  211      0.333557350649636e+02
  222     -0.971204842287534e+02

[dpb]

FileExchange didn't find anything but Gargle returned <HB_to_MSM> which has links to a library of m-files that purport to solve the problem.

Looking at the above, where in the header lines are the array dimensions? Looks like it would be simple enough to just textscan the file for what I presume is array nonzero element index in first column and value in second; all one needs is to know what the actual size is intended to be it would seem.

It isn't clear why there's a FORMAT statement of

 (I14)          (I14)           (d25.15)            (d25.15)

when are only two columns, though? Is something fouled up in the data as shown vis a vis actual file?

Attaching a segment of an actual file would help immeasurably along with how to interpret the associated header for the specific file.

[SERGIO A. ARDILA]

The first column should contain the indexes of every value in the second column as you can find here:

https://www.mathworks.com/matlabcentral/answers/69394-how-can-i-import-the-stiffness-matrix-generated-by-ansys-and-contained-in-a-file-txt?s_tid=srchtitle

The problem is how to convert those numbers from the first column into the indexes of the matrix.

[dpb]

Well, there's only one index; what's to convert? Is it the linear index into a 2D, 3D, ND array or just a vector? We don't know...

This file doesn't look anything like the other one in the link; don't see there's anything there that applies directly.

Is that all the data in that range; that is, you haven't just selected 1,28,54,... but that is the full file from 1 thru 54 (and so on)?

The key unknown here is just what size should the resulting array be?

[SERGIO A. ARDILA]

Yes you're right, indexes can't be determined easily, the file must be converted. I solved the problem exporting the matrix from ansys as Market Matrix Format. These codes help to import to matlab:

http://math.nist.gov/MatrixMarket/mmio/matlab/mmiomatlab.html

Thanks for your help.