[Gambas-user] curve fitting library ?

Wally wally at ...2037...
Mon Jan 23 11:31:44 CET 2012 

Do you think it's possible to create a gambas module, similar to 
"gb.db.sqlite3" or "gb.cairo"  but , lets say "gb.gsl" or "gb.math" ?
These gb.moduls seems to be able to use C++ Libraries.

Ok, most of the people which are able to to this, usually do not 
have time to do it. I have time but no experience, maybe some 
help in beginnig might be sufficient - at least for some simple 
finctionality. But may be this requires too much experience 
and i might not be helpful at all. What do you think ?



> Gambas had tools like GSL, Armadillo, PyLab, and Numpy


On Monday, January 23, 2012 01:03:06 Randall Morgan wrote:
> Wally,
> 
> SG and RDP both would do a decent job for you since you need to preserve
> your peaks. I don't have code for this but you can find psuedo code for it
> on Wikipedia. The sudo code should be easy to convert into Gambas. It would
> be nice if one Gambas had tools like GSL, Armadillo, PyLab, and Numpy. I
> think it will get there but not anytime soon. Still RDP does not need any
> external libraries. You can use the built in math functions. You don't need
> a coefficients like  you do with SG. SG will give better over-all
> smoothing. But under Gambas would require a lot more work.
> 
> As for porting GSL to Gambas that is not a trivial task. Not impossible but
> it's not something you'll do in a few hours... I've ported much of the TIdy
> Library to Gambas for use with data extraction and web crawling. But it
> took me weeks to do only a portion of the library.
> 
> Hope this helps
> 
> On Mon, Jan 23, 2012 at 12:38 AM, Wally <wally at ...2037...> wrote:
> > The signal data i want to process comes from a HPLC detctor, which
> > generates analog voltage outputs. e.g. every second one meqasurement.
> > The data is typical chromatography data as generated by several
> > spectroscopic methods.
> > The time base can be set to different values but mostly i use 1 Hz.
> > A 16bit ADc convert this analog data to digital float values
> > So i get a list of "Y"values with constant time-delta.
> > The data is noisy - so i uesed in 1st step Sawatzky-Golay smoothing.
> > 
> > These data contains usually few peaks which i need to find. I need
> > maximumvalue, time value of maximum, half-height-width and area of
> > every single peak. Sometimes peaks are very close so area is
> > overlapping.
> > 
> > The fityk-package is doing all this jobs very simple but i can not use
> > in
> > gambas. Another candidate, which is suitable to use with ganbas is
> > Gnu Scientific Library. There are a lot of numerical functions
> > available,
> > but accessing this functions, was so far, too  difficult for me to code
> > with
> > gambas. I always mess up all the pointer stuff needed to declare and
> > access this functionality. So i ask here to find a simple plain C
> > library  or Gambas-, even VB-code to do this jobs.
> > 
> > wally
> > 
> > On Monday, January 23, 2012 00:06:49 Randall Morgan wrote:
> > > Most of the stuff I did in signal processing was on the 68000 and
> > > Z80's.> 
> > So
> > 
> > > I let most of that go a very long time ago. Besides, unless you know
> > > what you are looking for in a smoothing algorithm, any code would
> > > be useless. For example, the simplest algorithm for smoothing is
> > > the moving average method. It's very simple to write in any
> > > programming language. Simple decide on the number of data points
> > > you are going to track and then> 
> > average
> > 
> > > the value of that many points. That average becomes you first point.
> > 
> > Slide
> > 
> > > the window up one value (or more, as long as there is plenty of
> > > overlap), allowing the low value(s) to fall out of the window, then
> > > calculate the average again. and plot your next point. Continue
> > > until you're out of> 
> > input
> > 
> > > data.
> > > 
> > > This issue with the moving average method is that you will flatten
> > > your
> > > data and loose your peaks. Since you have not said what your data is
> > 
> > being
> > 
> > > used for or how you are getting it, it is impossible to guess what
> > > method of smoothing would be appropriate. So you need to ask
> > > yourself, are my peaks important? Is my data timed? What am I doing
> > > with it once I smooth> 
> > it
> > 
> > > out? If you are displaying it, what information in your data is
> > > important to convey to the viewer? Etc... Without details no one
> > > can really help> 
> > you.
> > 
> > > Give me specifics and perhaps I can be of more help.
> > > 
> > > On Sun, Jan 22, 2012 at 11:44 PM, Wally <wally at ...2037...> wrote:
> > > > I assume you do not have a code  example, right  ?
> > > > 
> > > > On Sunday, January 22, 2012 17:02:17 Randall Morgan wrote:
> > > > > Just a thought,
> > > > > 
> > > > > You could write a callable wrapper around numpy then call
> > > > > that from
> > > > 
> > > > Gambas.
> > > > 
> > > > > Would give you all the power of the python numerical library
> > > > > from
> > > > > within Gambas.
> > > > > 
> > > > > On Sun, Jan 22, 2012 at 2:18 AM, Randall Morgan
> > > > > <rmorgan62 at ...626...>
> > > > 
> > > > wrote:
> > > > > > Not with Gambas and it's been a long while. But if you
> > > > > > understand the
> > > > > > algorithms used and the type of curve fitting you desire
> > > > > > for
> > > > > > your
> > > > > > problem
> > > > > > domain then implementing it in Gambas is not a problem.
> > > > > > 
> > > > > > You may want to google curve fitting algorithms. You
> > > > > > need to
> > > > > > know if
> > > > 
> > > > you
> > > > 
> > > > > > want a linear, polynomial, rational, cubic, or nonlinear
> > > > > > fitting. Then find a C/C++/Python implementation and
> > > > > > flow chart
> > > > > > the algorithm. Then you  can easily convert it to Gambas
> > > > > > or any
> > > > > > programming language.> > >
> > > > > > 
> > > > > > On Sun, Jan 22, 2012 at 12:54 AM, Wally <wally at ...2037...> wrote:
> > > > > >> Does anyone have experience with curve fitting and/or
> > > > > >> peakfinding
> > > > > >> using gambas ?    (e.g. example code)
> > > > > >> 
> > > > > >> Is there a plain C library (Linux) known, suitable to
> > > > > >> this
> > > > > >> problem
> > > > > >> and gambas ?
> > > > > >> 
> > > > > >> Something like "fityk" (which is written in C++) but
> > > > > >> written
> > > > > >> in plain C
> > > > > >> to use with "EXTERN"
> > > > > >> 
> > > > > >> I might wrap the fityk C++ or try Gnu Scientific
> > > > > >> Library, but
> > > > > >> i'm
> > > > > >> still
> > > > > >> searching for alternatives.
> > > > > >> 
> > > > > >> wally
> > > > > >> 
> > > > > >> 
> > > > > >> 
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> > > > > > If you ask me if it can be done. The answer is YES, it
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> > > > > > always be
> > > > > > done. The correct questions however are... What will it
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> > > > > > and how
> > > > > > long will it take?
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