Re: Test failure for fftfilt.m

[Ed Meyer]

On Sat, Mar 16, 2013 at 4:28 PM, Daniel J Sebald <address@hidden> wrote:

On 03/16/2013 05:18 PM, Ed Meyer wrote:

I fixed the tests last fall according to what I consider the right way to
do tests like this. As I have said several times before tests should not
in general use absolute tolerances, rather they should take into account
the size of the data. So for example instead of

assert (fftfilt (b, r * x),r * r * [1, 1, 0, 0, 0, 0, 0, 0, 0, 0],eps)

I used

%! y = r*r*[1 1 0 0 0 0 0 0 0 0];
%! tol = 2*norm(y)*eps;
%! assert (fftfilt (b, r*x), y, tol);

There are a number of tests like this (eig.cc for example) with absolute
tolerances which should be using norms. But don't take my word for it,
see, e.g. Golub & Van Loan, "Matrix Computations".

Yes, I'm a bit sketchy, but I remember looking at the work you had done.  I thought you checked it in.  But this file log would suggest it wasn't:

http://hg.savannah.gnu.org/hgweb/octave/log/7d0848353eaf/scripts/signal/fftfilt.m

Dan

As I recall you made some changes that wiped out what I sent you and we
never got them back in before you checked it in. I could put a patch up but
for some reason other patches I've put up don't get applied so there is something
I don't understand about the process.


-- 
Ed Meyer