[time-nuts] exponential+linear fit

[Jim Lux]

On 10/7/13 2:44 PM, Magnus Danielson wrote:
> Which reminds me, there is a nifty tool called fityk that I tend to use
> just to view graphs, but has a rather nice set of routines to do various
> fits to various curves.
>

gnuplot's not bad, either..

you define a function f(x) and the free parameters, define some starting 
values, kick off the fit, and let it roll.

so I did
f(x) = a + b*x + c*exp(d*x)
with some starting values picked by eye

and it did an ok job with the fit.
It is NOT speedy though.. It's an iterative solution and takes a good 30 
seconds on my macbook air to fit the 6000 data points I have.