changing algorithm, finding residuals w/FindFit

• To: mathgroup at smc.vnet.net
• Subject: [mg56714] changing algorithm, finding residuals w/FindFit
• From: Edward Peschko <esp5 at pge.com>
• Date: Wed, 4 May 2005 00:34:20 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```hey all,

I was wondering if there was a integral way to get the residuals that that least
squares fit offered:

points = { { 1,2 } , { 3, 4 } , {5,6} };

fit = FindFit[points, c + d x + e x^2, {c,d,e}, x];

{ c -> ..., d -> ..., e -> ... }

residuals = Residual[points, c + d + e x^2 /. fit, ResidualType -> squarex ],

I would think that there would be a oneliner (or oneliner function) to express this
succinctly, but I'm having difficulty expressing it.. The closest I could
get to in perl is:

@points = ( [1,2], [3,4], [5,6] );
@residuals = map( [ \$_->[0], (\$_->[1] - &\$function(\$_->[0]))**2 ], @\$points);

Also, is there a way to change the method which is used for FindFit and
FindMinimum/FindMaximum? I see there's a Method attribute, but there doesn't
seem to be any options for setting it, other than 'Automatic'. In particular,
I'd like to use adaptive simulated annealing:

http://www.ingber.com/#ASA

for more complicated functons..

Ed

```

• Prev by Date: Re: debugging
• Next by Date: Re: books on writing packages