[SciPy-user] 2d interpolation (Michael Hearne)

Alex Liberzon alex.liberzon@gmail....
Wed Aug 1 16:43:00 CDT 2007


It doesn't fit because xi and yi are 1:.5:4 in Matlab but 0:.5:3 in Python
I tested it with
outgrid(arange(1,4.1,.5),arange(1,4.1,.5)) and the result is the same
as in Matlab.

Best
Alex

On 8/2/07, scipy-user-request@scipy.org <scipy-user-request@scipy.org> wrote:
> Send SciPy-user mailing list submissions to
>         scipy-user@scipy.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         http://projects.scipy.org/mailman/listinfo/scipy-user
> or, via email, send a message with subject or body 'help' to
>         scipy-user-request@scipy.org
>
> You can reach the person managing the list at
>         scipy-user-owner@scipy.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of SciPy-user digest..."
>
>
> Today's Topics:
>
>    1. Re: Ant Colony Optimization (Alan G Isaac)
>    2. Re: General Python Question: nested function calls (Ryan Krauss)
>    3. Re: General Python Question: nested function calls
>       (Gael Varoquaux)
>    4. Re: Finding Neighboors (Barry Wark)
>    5. Re: Finding Neighboors (jelle)
>    6. Re: Testing BOF at scipy'07? (Fernando Perez)
>    7. 2d interpolation (Michael Hearne)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Wed, 1 Aug 2007 15:58:34 -0400
> From: Alan G Isaac <aisaac@american.edu>
> Subject: Re: [SciPy-user] Ant Colony Optimization
> To: scipy-user@scipy.org
> Message-ID: <Mahogany-0.67.0-1600-20070801-155834.00@american.edu>
> Content-Type: TEXT/PLAIN; CHARSET=UTF-8
>
> On Wed, 01 Aug 2007, "Brandon C. Nuttall" apparently wrote:
> > Is there an implementation of the Ant Colony Optimization
> > routines available in Python? See
> > http://www.aco-metaheuristic.org/
>
> You could wrap the C code at:
>    http://www.aco-metaheuristic.org/aco-code/public-software.html
>
> fwiw,
> Alan Isaac
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 1 Aug 2007 14:56:59 -0500
> From: "Ryan Krauss" <ryanlists@gmail.com>
> Subject: Re: [SciPy-user] General Python Question: nested function
>         calls
> To: "SciPy Users List" <scipy-user@scipy.org>
> Message-ID:
>         <c5b438120708011256x2d0ebbeaw79d2514b285f21b@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> That would have been a better solution in this case - I have done that
> before and don't know why I didn't here.
>
> Any thoughts on the same situation with calling a parent class's
> method.  I just wrote code that did this:
> def __init__(self, pathin=None, dialect=spreadsheet.tabdelim):
>         ....
>         spreadsheet.SpreadSheet.__init__(self, pathin=pathin,
> skiprows=0, collabels=collabels, colmap=colmap, datafunc=float,
> picklekeys=['t','lg','a','v0'])
>
> Basically, I do a few other things and then call the parent's __init__
> somewhere in the middle.
>
> On 8/1/07, Robert Kern <robert.kern@gmail.com> wrote:
> > Ryan Krauss wrote:
> > > I often write code something like this:
> > >
> > > def TruncatePickleFile(pathin, trigname='a', trigtype='sw',
> > > savepath=None, threshlevel=None, duration=0.05, backup=0.01):
> > >     """Trunate the pickleddatafile whose path is pathin.  If
> > >     trigtype=='lg', use a DropDownLightGateTrigger, else use a
> > >     standard Trigger."""
> > >     untrunc = pickleddatafiles.PickledDataFile(pathin)
> > >     mytrunc = pickleddatafiles.TruncateDataObj(untrunc,
> > > threshlevel=threshlevel, backup=backup, duration=duration)
> > >     mytrunc.chname = trigname
> > >     if trigtype == 'lg':
> > >         mytrunc.SetupTrigger(DataProcMixins.DropDownLightGateTrigger)
> > >     else:
> > >         mytrunc.SetupTrigger()
> > >     mytrunc.SetupTruncChannel()
> > >     mytrunc.Truncate()
> > >     pathout = mytrunc.Pickle(savepath)
> > >     return pathout
> > >
> > > def TruncatePickleFiles(listin, trigname='a', trigtype='sw',
> > > threshlevel=None, duration=0.05, backup=0.01):
> > >     listout = []
> > >     for item in listin:
> > >         print item
> > >         curpath = TruncatePickleFile(item, trigname=trigname,
> > > trigtype=trigtype, threshlevel=threshlevel, duration=duration,
> > > backup=backup)
> > >         listout.append(curpath)
> > >     return listout
> > >
> > > where TruncatePickleFiles is sort of just a vectorization of
> > > TruncatePickleFile, but with some of the keyword args set.  My problem
> > > is not that this might not be the fastest way to execute the code, but
> > > that I get tired of doing this kind of stuff:
> > >
> > > curpath = TruncatePickleFile(item, trigname=trigname,
> > > trigtype=trigtype, threshlevel=threshlevel, duration=duration,
> > > backup=backup)
> > >
> > > but I also don't want to just do
> > >
> > > def TruncatePickleFiles(listin, **kwargs):
> > >
> > > because I like to see the defaults and know what keyword arguments are legal.
> > >
> > > Does anyone else have this problem or have an elegant solution to it?
> > > The problem comes up for me also when I want a derived class to call a
> > > parent class's method in some partially overwritten method of the
> > > derived class.
> > >
> > > Ideally, I think I would like to pass **kwargs to the nested function,
> > > but without using **kwargs in the definition of the top function, if
> > > that makes any sense.
> >
> > There isn't really a straightforward solution.
> >
> > However, for something like this, you may want to consider just implementing one
> > version of the function which can take either a list of filenames or a single
> > filename.
> >
> > --
> > Robert Kern
> >
> > "I have come to believe that the whole world is an enigma, a harmless enigma
> >  that is made terrible by our own mad attempt to interpret it as though it had
> >  an underlying truth."
> >   -- Umberto Eco
> > _______________________________________________
> > SciPy-user mailing list
> > SciPy-user@scipy.org
> > http://projects.scipy.org/mailman/listinfo/scipy-user
> >
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 1 Aug 2007 22:22:32 +0200
> From: Gael Varoquaux <gael.varoquaux@normalesup.org>
> Subject: Re: [SciPy-user] General Python Question: nested function
>         calls
> To: SciPy Users List <scipy-user@scipy.org>
> Message-ID: <20070801202232.GB29@clipper.ens.fr>
> Content-Type: text/plain; charset=iso-8859-1
>
> On Wed, Aug 01, 2007 at 02:56:59PM -0500, Ryan Krauss wrote:
> > That would have been a better solution in this case - I have done that
> > before and don't know why I didn't here.
>
> > Any thoughts on the same situation with calling a parent class's
> > method.  I just wrote code that did this:
> > def __init__(self, pathin=None, dialect=spreadsheet.tabdelim):
> >         ....
> >         spreadsheet.SpreadSheet.__init__(self, pathin=pathin,
> > skiprows=0, collabels=collabels, colmap=colmap, datafunc=float,
> > picklekeys=['t','lg','a','v0'])
>
> > Basically, I do a few other things and then call the parent's __init__
> > somewhere in the middle.
>
> I had a similar problem recently and resolved it using a complex
> machinery (my requirements where a bit more complex than only this). I
> used traits, but you could do this without traits (though it would be
> harder).
>
> The thread concerning this problem and its solution can be found at
> https://mail.enthought.com/pipermail/enthought-dev/2007-August/007820.html
>
> This is heavy machinery, but there are some ideas to steal.
>
> Ga?l
>
>
> ------------------------------
>
> Message: 4
> Date: Wed, 1 Aug 2007 13:31:58 -0700
> From: "Barry Wark" <barrywark@gmail.com>
> Subject: Re: [SciPy-user] Finding Neighboors
> To: "SciPy Users List" <scipy-user@scipy.org>
> Message-ID:
>         <cd7634ce0708011331pee2ede1y39e2e03fbb0a31bf@mail.gmail.com>
> Content-Type: text/plain; charset=WINDOWS-1252
>
> Hi all,
>
> Catching this conversation late. As jelle points out, BioPython has a
> k-d tree implemetation, but it hasn't been converted to numpy yet (I
> think it still uses Numeric). I've written a SWIG (with numpy type
> maps) wrapper around the Approximate Nearest Neighbor library
> (http://www.cs.umd.edu/~mount/ANN/), which includes both exact and
> approximate k-d tree searches. Email me off list if you would like a
> copy of the swig definition files. If there's interest, I will send it
> on to the ANN writers for inclusion in the library itself.
>
> Barry
>
> On 7/31/07, Emanuele Zattin <emanuelez@gmail.com> wrote:
> > Hi, you might want to take a look at kd-trees. No implementation in
> > scipy, but it should not be too hard to achieve. As far as i can
> > remember its definition in wikipedia includes some python code. Just
> > my 2 cents :)
> >
> > On 8/1/07, Matthieu Brucher <matthieu.brucher@gmail.com> wrote:
> > > Hi,
> > >
> > > I have an implementation, but it depends on my own matrix library... That's
> > > a stopper... But it works.
> > > I do not know the other templated matrix libraries very well, but I'd say I
> > > do not need much to make it work with another library.
> > >
> > > Matthieu
> > >
> > > 2007/8/1, Alan G Isaac <aisaac@american.edu>:
> > > > On Tue, 17 Apr 2007, Matthieu Brucher apparently wrote:
> > > > > I wanted to know if there was a module in scipy that is able to find the
> > > > > k-neighboors of a point ?
> > > > > If so, is there an optimized one - tree-based search - ?
> > > > > If not, I'm doing the optimized version.
> > > >
> > > > Hi Matthieu,
> > > >
> > > > Where did you go with this?
> > > >
> > > > Thanks!
> > > > Alan
> > > >
> > > >
> > > >
> > > >
> > > > _______________________________________________
> > > > SciPy-user mailing list
> > > > SciPy-user@scipy.org
> > > > http://projects.scipy.org/mailman/listinfo/scipy-user
> > > >
> > >
> > >
> > > _______________________________________________
> > > SciPy-user mailing list
> > > SciPy-user@scipy.org
> > > http://projects.scipy.org/mailman/listinfo/scipy-user
> > >
> > >
> >
> >
> > --
> > Emanuele Zattin
> > ---------------------------------------------------
> > -I don't have to know an answer. I don't feel frightened by not
> > knowing things; by being lost in a mysterious universe without any
> > purpose ? which is the way it really is, as far as I can tell,
> > possibly. It doesn't frighten me.- Richard Feynman
> > _______________________________________________
> > SciPy-user mailing list
> > SciPy-user@scipy.org
> > http://projects.scipy.org/mailman/listinfo/scipy-user
> >
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 1 Aug 2007 21:06:22 +0000 (UTC)
> From: jelle <jelleferinga@gmail.com>
> Subject: Re: [SciPy-user] Finding Neighboors
> To: scipy-user@scipy.org
> Message-ID: <loom.20070801T230532-760@post.gmane.org>
> Content-Type: text/plain; charset=us-ascii
>
> Terrific!
> ANN seems like a very useful module Barry!
> Thanks for pointing out!
>
> Cheers,
>
> -jelle
>
>
>
> ------------------------------
>
> Message: 6
> Date: Wed, 1 Aug 2007 15:14:25 -0600
> From: "Fernando Perez" <fperez.net@gmail.com>
> Subject: Re: [SciPy-user] Testing BOF at scipy'07?
> To: "SciPy Users List" <scipy-user@scipy.org>
> Message-ID:
>         <db6b5ecc0708011414n6545fe0fx359fe3615db310ee@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On 8/1/07, Karl Young <Karl.Young@ucsf.edu> wrote:
> >
> > Sounds great to me; I need to learn a lot more about developing good
> > testing practices (given that it doesn't conflict with the planned 3D
> > visualization BOF on Thursday evening as I've already agreed to be
> > counted for that).
>
> No worries, I also said I'd go to the Thursday viz one as well.
>
> I wonder if we could plan on 2 bofs a night.  Titus is already signed
> up as moderator for one on Thursday:
>
> http://scipy.org/SciPy2007/BoFs
>
> and I'd like to have him in for the testing one as well.  If we could
> plan something like
>
>       bof1             bof2
>
> 7-8   vis3d            bio
> 8-9   testing          astronomy
>
> then we could have Titus available for both and those of us who said
> yes to the vis3d one could also go to testing.
>
> Else we put the other bofs on Wednesday night, at the risk of getting
> less people in.  Friday is probably out, since a lot of people leave
> then...
>
> Opinions?
>
> f
>
>
> ------------------------------
>
> Message: 7
> Date: Wed, 1 Aug 2007 15:15:22 -0600
> From: Michael Hearne <mhearne@usgs.gov>
> Subject: [SciPy-user] 2d interpolation
> To: scipy-user@scipy.org
> Message-ID: <6F6365AF-B63F-4D6D-99BA-39D47179DA31@usgs.gov>
> Content-Type: text/plain; charset="us-ascii"
>
> All:  I'm trying to use interp2d to replicate behavior in Matlab.
>
> The Matlab script:
> x = reshape(1:16,4,4)';
> xi = 1:0.5:4;
> yi = [1:0.5:4]';
> z = interp2(x,xi,yi,'linear')
>
> which results in the matrix:
> z =
>
>      1.0000    1.5000    2.0000    2.5000    3.0000    3.5000    4.0000
>      3.0000    3.5000    4.0000    4.5000    5.0000    5.5000    6.0000
>      5.0000    5.5000    6.0000    6.5000    7.0000    7.5000    8.0000
>      7.0000    7.5000    8.0000    8.5000    9.0000    9.5000   10.0000
>      9.0000    9.5000   10.0000   10.5000   11.0000   11.5000   12.0000
>     11.0000   11.5000   12.0000   12.5000   13.0000   13.5000   14.0000
>     13.0000   13.5000   14.0000   14.5000   15.0000   15.5000   16.0000
>
> I had thought the following Python/numpy script would be equivalent,
> but it is not:
> from scipy.interpolate import interpolate
> from numpy.random import randn
> from numpy import *
>
> data = arange(16)
> data = data+1
> data = data.reshape(4,4)
> xrange = arange(4)
> yrange = arange(4)
> X,Y = meshgrid(xrange,yrange)
>
> outgrid = interpolate.interp2d(X,Y,data,kind='linear')
> xi = array([0,0.5,1,1.5,2,2.5,3])
> yi = xi
>
> z = outgrid(xi,yi)
>
> This results in the matrix:
> [[  1.           1.10731213   2.           2.89268787   3.
> 3.25045605
>      4.        ]
> [  3.           2.57118448   4.           5.42881552   5.
> 4.90975947
>      6.        ]
> [  5.           4.03505682   6.           7.96494318   7.
> 6.56906289
>      8.        ]
> [  7.           5.49892917   8.          10.50107083   9.
> 8.22836631
>     10.        ]
> [  9.           6.96280152  10.          13.03719848  11.
> 9.88766973
>     12.        ]
> [ 11.           8.42667386  12.          15.57332614  13.
> 11.54697315
>     14.        ]
> [ 13.           9.89054621  14.          18.10945379  15.
> 13.20627657
>     16.        ]]
>
> (Incidentally, is there a way to pretty-print arrays in numpy?  The
> above is kind of ugly and hard to read)
>
> Is this some kind of spline interpolation that I don't understand?
>
> Thanks,
>
> Mike Hearne
>
>
>
>
>
>
> ------------------------------------------------------
> Michael Hearne
> mhearne@usgs.gov
> (303) 273-8620
> USGS National Earthquake Information Center
> 1711 Illinois St. Golden CO 80401
> Senior Software Engineer
> Synergetics, Inc.
> ------------------------------------------------------
>
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: http://projects.scipy.org/pipermail/scipy-user/attachments/20070801/5ae71590/attachment.html
>
> ------------------------------
>
> _______________________________________________
> SciPy-user mailing list
> SciPy-user@scipy.org
> http://projects.scipy.org/mailman/listinfo/scipy-user
>
>
> End of SciPy-user Digest, Vol 48, Issue 6
> *****************************************
>


More information about the SciPy-user mailing list