[Octave-bug-tracker] [bug #61305] In linear-algebra/null.m function, line 63 should use upper case S instead of the lower case s. rank = sum (S > tol)

[Arun Giridhar]

Follow-up Comment #1, bug #61305 (project octave):

@OP, can you provide more context about what you were trying to do, what you
got, and what you think the result should be?

For context, the function null.m is reproduced here with line numbers. The
line "rank = sum (...." part is on line 66 below.


    41  function Z = null (A, tol)
    42  
    43    if (nargin < 1)
    44      print_usage ();
    45    elseif (nargin == 2 && strcmp (tol, "r"))
    46      error ("null: option for rational not yet implemented");
    47    endif
    48  
    49    [~, S, V] = svd (A, 0);  # Use economy-sized svd if possible.
    50  
    51    ## In case of A = [], zeros (0,X), zeros (X,0) Matlab R2020b seems
to
    52    ## simply return the nullspace "V" of the svd-decomposition (bug
#59630).
    53    if (isempty (A))
    54      Z = V;
    55    else
    56      out_cls = class (V);
    57  
    58      if (rows (A) > 1)
    59        s = diag (S);
    60      else
    61        s = S.';
    62      end
    63      if (nargin == 1)
    64        tol = max (size (A)) * s(1) * eps (out_cls);
    65      endif
    66      rank = sum (s > tol);
    67  
    68      cols = columns (A);
    69      if (rank < cols)
    70        Z = V(:, rank+1:cols);
    71        Z(abs (Z) < eps (out_cls)) = 0;
    72      else
    73        Z = zeros (cols, 0, out_cls);
    74      endif
    75    endif
    76  
    77  endfunction



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