numpy (matrix solver) - python vs. matlab

[someone]

On 05/01/2012 10:54 PM, Russ P. wrote:
> On May 1, 11:52 am, someone<newsbo... at gmail.com>  wrote:
>> On 04/30/2012 03:35 AM, Nasser M. Abbasi wrote:

>> What's the limit in matlab (on the condition number of the matrices), by
>> the way, before it comes up with a warning ???
>
> The threshold of acceptability really depends on the problem you are
> trying to solve. I haven't solved linear equations for a long time,
> but off hand, I would say that a condition number over 10 is
> questionable.

Anyone knows the threshold for Matlab for warning when solving x=A\b ? I 
tried "edit slash" but this seems to be internal so I cannot see what 
criteria the warning is based upon...

> A high condition number suggests that the selection of independent
> variables for the linear function you are trying to fit is not quite
> right. For a poorly conditioned matrix, your modeling function will be
> very sensitive to measurement noise and other sources of error, if
> applicable. If the condition number is 100, then any input on one
> particular axis gets magnified 100 times more than other inputs.
> Unless your inputs are very precise, that is probably not what you
> want.
>
> Or something like that.

Ok. So it's like a frequency-response-function, output divided by input...