Segmentation faults when using sparse matrices about nmatrix HOT 8 CLOSED

It will be fixed but I suspect that you have some misconceptions about a list matrix.

1. A list matrix has default value (by default it equals zero). You will get this value always when you access to non-existent element of the matrix. After creation a list matrix is empty, but we see it as filed by zero. When you assign to a cell default value you actually remove it. In this way, your code (if it works) does nothing.

2. If you want to fill your matrix fully or bigger part. To be better use a dense matrix.

Thanks for report, if @MohawkJohn will not be against I can fix up this bug.

from nmatrix.

For (2) most of the values I'm setting are 0. I'm using a sparse matrix as a vector space model.

For (1), I don't understand, "your code (if it works) does nothing". For example, this works fine:

matrix = NMatrix.new(:list, [2, 2], :float64)
matrix.pretty_print

Prints:

0.0  0.0
0.0  0.0

Then:

matrix[0, 0] = 1
matrix.pretty_print

Gives:

1.0  0.0
0.0  0.0

My code is doing the same thing as above, except inside loops.

from nmatrix.

(1) Sorry. I have understood what you fill a matrix by zero values. And from (2) I agree that your choice of type matrix is right.

Well.. we will fix it as soon as it possible. Thank you very mach for report again.

from nmatrix.

Forgot to mention: this is with 0.0.1 release. I will test with HEAD as soon as I can install it.

from nmatrix.

It's very important because 0.0.2 is very differ from 0.0.1 inwardly. Actually 0.0.2 is result of deep refactoring and a big part had been rewritten in C++.

I will check up it for 0.0.2.

from nmatrix.

For 0.0.2 this code works right:

    m = NMatrix.new(:list, [3, 3], :float64)
    [1.0,2.0,3.0].each_with_index do |x,i|
      [1.0,2.0,3.0].each_with_index do |y,j|
        m[i, j] = x+y
      end
    end
    m.pretty_print

Pleas try it again when you will have installed 0.0.2 version.

from nmatrix.

Is this working for you now, @jpmckinney? Thanks, Aleksey, for working on this.

from nmatrix.

My code works with :list now, thanks! And I'm able to cast it to :yale after building it.

from nmatrix.