Re: time-nuts Digest, Vol 111, Issue 21 On Sat, 05 Oct 2013 11:54:08 -0400, time-nuts-requ...@febo.com wrote: > > Message: 6 > Date: Sat, 05 Oct 2013 08:53:52 -0700 > From: Jim Lux <jim...@earthlink.net> > To: time-nuts@febo.com > Subject: Re: [time-nuts] exponential+linear fit > Message-ID: <52503610.4040...@earthlink.net> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > On 10/5/13 8:47 AM, Tim Shoppa wrote: >> How slow of a processor are you working with? A modern PC using a general >> purpose graphing and fitting tool (e.g. gnuplot) will fit tens of thousands >> of points in a fraction of a second. >> http://people.duke.edu/~hpgavin/gnuplot.html >> >> If you want to do this in your own code, there are lots of least-squares >> fitting examples in every first year numerical analysis textbook in every >> computer language ever written (I learned this in FORTRAN 4 naturally). >> http://en.wikipedia.org/wiki/Least_squares >> >> If you have hardware substantially more primitive (e.g. a PIC, a bag of >> 2N2222's and 555's, etc.) you have to do the fit on, then it's an >> interesting problem :-) >> > > In the future, more the latter than the former. 48 MHz ARM Cortex-M4, > for instance. > > For now, though, yeah, it's on a not very fast PC (Windows Experience > Rating around 2), but compiled matlab does it very quickly. But, given > that sooner or later I'm going to be heading for a more resource > constrained environment, or trying to FPGA it, I'm looking for simple > algorithms to implement the simplified models. > > And, of course, I don't want to drag in all the libraries that one gets > with Matlab,Octave,gnuplot, etc. > > They're great for figuring out what's going on and trying out the > algorithms.
There are lots of suitable subroutines available in "Numerical Recipes in C" by Press et al, that can be used as is, or as the starting point. <http://apps.nrbook.com/c/index.html> Joe Gwinn _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.