[Octave-bug-tracker] [bug #58324] regress.m: Calling on two identical data sets causes divide by zero

[Ben Brown]

URL:
  <https://savannah.gnu.org/bugs/?58324>

                 Summary: regress.m: Calling on two identical data sets causes
divide by zero
                 Project: GNU Octave
            Submitted by: benbrown
            Submitted on: Thu 07 May 2020 04:07:39 PM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Missed Error or Warning
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: 5.2.0
         Discussion Lock: Any
        Operating System: Any

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Details:


X = [ones(size(data)) data];
y = data;

[~,~,~,~,stats] = regress(y,X);

warning: division by zero
warning: called from
    regress at line 171 column 7


in regress.m


167: R2 = 1 - SSE / sum ((y - mean (y)) .^ 2);
171: F = dof / (p - 1) / (1 / R2 - 1);


But R2 = 1 as there are no residual errors

I changed to:


if (R2 < 1)
  F = dof / (p - 1) / (1 / R2 - 1);
else
  F = Inf;
end





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