Re: 3.2.3 RC2

[Marco Atzeri]

--- Mer 2/9/09, John W. Eaton <address@hidden> ha scritto:

 
> I also see this failure, but it doesn't happen on every
> run.  I'm
> running Octave on an amd64 system.
> 
> The test is:
> 
>   n = 100;
>   k = 7;
>   a =
> sparse([3:n,1:n,1:(n-2)],[1:(n-2),1:n,3:n],[ones(1,n-2),0.4*n*ones(1,n),ones(1,n-2)]);
>   [u,s,v] = svd(full(a));
>   s = diag(s);
>   [dum, idx] = sort(abs(s));
>   s = s(idx);
>   u = u(:,idx);
>   v = v(:,idx);
>   [u2,s2,v2,flag] = svds(a,k,0);
>   s2 = diag(s2);
>   assert(flag,!1);
>   assert(s(k:-1:1), s2, 1e-10); 
> 
> If you run this repeatedly, do you see some successes and
> some
> failures?  If it does fail, do you see that the first
> assert sometimes
> fails, and other times it is the second?
> 
> I have not tried to debug the problem yet.
> 
> David, I'm copying you because you wrote svds and might be
> able to see
> the problem and perhaps a fix more quickly than I could.
> 
> Thanks,
> 
> jwe
> 

just tested on 3.2.3-RC1 on cygwin

first OK

second
warning: returning fewer singular values than requested
warning: try increasing the value of sigma

third
 error: assert (s (k:-1:1),s2,1e-10) expected
   38.034
   38.034
   38.015
   38.015
   38.004
   38.004
but got
   38.060
   38.034
   38.034
   38.015
   38.015
   38.004
   38.004
Dimensions don't match
error: called from:


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Marco