Re: fsolve test failure

[Jaroslav Hajek]

On Thu, Jan 29, 2009 at 8:57 PM, John W. Eaton <address@hidden> wrote:
> On 28-Jan-2009, Jaroslav Hajek wrote:
>
> | I've uploaded a patch that relaxes the strict scaling:
> |
> |
> | this makes the results with default settings more plausible:
> |  function retval = f (p)
> |    x = p(1);
> |    y = p(2);
> |    z = p(3);
> |    w = p(4);
> |    retval = zeros (4, 1);
> |    retval(1) = 3*x + 4*y + exp (z + w) - 1.007;
> |    retval(2) = 6*x - 4*y + exp (3*z + w) - 11;
> |    retval(3) = x^4 - 4*y^2 + 6*z - 8*w - 20;
> |    retval(4) = x^2 + 2*y^3 + z - w - 4;
> |  endfunction
> |
> |  x_opt = [ -0.767297326653401, 0.590671081117440, 1.47190018629642,
> | -1.52719341133957 ];
> |   tol = 1.0e-5;
> |   [x, fval, info, out] = fsolve (@f, [-1, 1, 2, -1])
> |   [x, fval, info, out] = fsolve (@f, [-1, 1, 2, -1], optimset
> | ("Updating", "off"))
>
> In this test, what is the purpose of tol?  I think that confused me as
> well as I didn't notice at first that it is unused.  Was it intended
> to be used in some way?
>

I think in the test tol is used in the subsequent assert statements.
Here, it remained just because I lazily copied the code.
Maybe the tests should be modified so that they reflect fsolve's
terminating condition. That needs querying the jacobian.


> | PS. I'll also commit the patch to make optimset/optimget case insensitive.
>
> OK.
>

I slightly hesitated with this - what, in your opinion, is the better
way to proceed?

1. let both optimset & optimget convert their args to lowercase.
2. leave optimset untouched, and write optimget in such a way that the
query is case-insensitive.

1. is easier and faster, because 2. probably requires looping through
the fields, but does not preserve case of options set.

> Thanks,
>
> jwe
>



-- 
RNDr. Jaroslav Hajek
computing expert
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz