[Octave-bug-tracker] [bug #43098] "if (array)" should raise a warning, and give the same result for dense and sparse

[Rik]

Follow-up Comment #13, bug #43098 (project octave):

Poor Lachlan, endless code review.  But, the code is definitely getting
cleaner and tighter.  I had a question about testing for NaN values.


+bool
+Sparse<T>::SparseRep::any_element_is_nan (void) const
+{
+  octave_idx_type nz = nnz ();
+
+  for (octave_idx_type i = 0; i < nz; i++)
+    if (d[i] != d[i])
+      return true;
+
+  return false;
+}


You're relying on an IEEE floating point trick that NaN != NaN.  This works,
but it is a little unclear.  Would it not be better to use
octave::math::isnan() as is done elsewhere in the codebase?

Second, does it make sense to add a specialization for SparseBool matrices for
this any_element_is_nan function?  For SparseBool, the element type T is bool
which can never be NaN and therefore the function could return false
immediately.



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