| Piecewise curve fitting in idl [message #61798] |
Thu, 31 July 2008 03:30  |
d.poreh
Messages: 406
Registered: October 2007
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Senior Member |
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Folks
How we can do the piecewise curve fitting in idl. Say we have an array
that this array has got 2 or 3 trends in data and we want to fit a
liner curve for each trends. In MATLAB curve fitting tool, we can
easily exclude or include a part of data and then fit a curve. How we
can do this in IDL
Cheers
Dave
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| Re: Piecewise curve fitting in idl [message #61896 is a reply to message #61798] |
Mon, 04 August 2008 03:01  |
d.poreh
Messages: 406
Registered: October 2007
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Senior Member |
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On Aug 4, 10:54 am, "jsch...@gmail.com" <jsch...@gmail.com> wrote:
> On Aug 4, 6:46 am, d.po...@gmail.com wrote:
>
>
>
>> On Aug 4, 6:58 am, Craig Markwardt
>
>> <craigm...@REMOVEcow.physics.wisc.edu> wrote:
>>> d.po...@gmail.com writes:
>>>> On Jul 31, 1:21 pm, Wox <nom...@hotmail.com> wrote:
>>>> > On Thu, 31 Jul 2008 03:30:22 -0700 (PDT), d.po...@gmail.com wrote:
>>>> > >Folks
>>>> > >How we can do the piecewise curve fitting in idl. Say we have an array
>>>> > >that this array has got 2 or 3 trends in data and we want to fit a
>>>> > >liner curve for each trends. In MATLAB curve fitting tool, we can
>>>> > >easily exclude or include a part of data and then fit a curve. How we
>>>> > >can do this in IDL
>>>> > >Cheers
>>>> > >Dave
>
>>>> > Euhm, just do the fitting on the different parts? Or do you mean
>>>> > fitting with a piecewise polynomial (i.e. spline: see e.g. IMSL_BSLSQ
>>>> > or IMSL_CONLSQ)
>
>>>> just doing the fitting on the difrent part. how we can select this
>>>> parts and how we can fit a curve to these parts separatly?
>
>>> I realize I'm coming into this discussion late. However, the IDL
>>> Astronomy library has a nice procedure LINTERP which would be very
>>> useful for an application like this. It would still need to be
>>> interfaced to a fitting function. It would allow you to fit the
>>> tabulated Y values, and in principle even the tabulated-X positions,
>>> although I would NOT advise that.
>
>>> For a graphical interface, IDL is probably not the best application
>>> unless you want to write the whole program yourself.
>
>>> Craig
>
>>> --
>>> ------------------------------------------------------------ --------------
>>> Craig B. Markwardt, Ph.D. EMAIL: craigm...@REMOVEcow.physics.wisc.edu
>>> Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
>>> ------------------------------------------------------------ --------------
>
>> could you please send me the Astronomy library link for this.
>> Cheers
>
> Would it really be all that difficult to Google ``LINTERP'' and ``IDL
> Astronomy Library'' ?
>
> http://idlastro.gsfc.nasa.gov/ftp/pro/math/linterp.pro
>
> Josiah
thanks!! sorry i am new in idl.
Cheers
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| Re: Piecewise curve fitting in idl [message #61897 is a reply to message #61798] |
Mon, 04 August 2008 01:54 |
jschwab@gmail.com
Messages: 30
Registered: December 2006
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Member |
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On Aug 4, 6:46 am, d.po...@gmail.com wrote:
> On Aug 4, 6:58 am, Craig Markwardt
>
>
>
> <craigm...@REMOVEcow.physics.wisc.edu> wrote:
>> d.po...@gmail.com writes:
>>> On Jul 31, 1:21 pm, Wox <nom...@hotmail.com> wrote:
>>>> On Thu, 31 Jul 2008 03:30:22 -0700 (PDT), d.po...@gmail.com wrote:
>>>> >Folks
>>>> >How we can do the piecewise curve fitting in idl. Say we have an array
>>>> >that this array has got 2 or 3 trends in data and we want to fit a
>>>> >liner curve for each trends. In MATLAB curve fitting tool, we can
>>>> >easily exclude or include a part of data and then fit a curve. How we
>>>> >can do this in IDL
>>>> >Cheers
>>>> >Dave
>
>>>> Euhm, just do the fitting on the different parts? Or do you mean
>>>> fitting with a piecewise polynomial (i.e. spline: see e.g. IMSL_BSLSQ
>>>> or IMSL_CONLSQ)
>
>>> just doing the fitting on the difrent part. how we can select this
>>> parts and how we can fit a curve to these parts separatly?
>
>> I realize I'm coming into this discussion late. However, the IDL
>> Astronomy library has a nice procedure LINTERP which would be very
>> useful for an application like this. It would still need to be
>> interfaced to a fitting function. It would allow you to fit the
>> tabulated Y values, and in principle even the tabulated-X positions,
>> although I would NOT advise that.
>
>> For a graphical interface, IDL is probably not the best application
>> unless you want to write the whole program yourself.
>
>> Craig
>
>> --
>> ------------------------------------------------------------ --------------
>> Craig B. Markwardt, Ph.D. EMAIL: craigm...@REMOVEcow.physics.wisc.edu
>> Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
>> ------------------------------------------------------------ --------------
>
> could you please send me the Astronomy library link for this.
> Cheers
Would it really be all that difficult to Google ``LINTERP'' and ``IDL
Astronomy Library'' ?
http://idlastro.gsfc.nasa.gov/ftp/pro/math/linterp.pro
Josiah
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| Re: Piecewise curve fitting in idl [message #61900 is a reply to message #61798] |
Sun, 03 August 2008 22:46 |
d.poreh
Messages: 406
Registered: October 2007
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Senior Member |
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On Aug 4, 6:58 am, Craig Markwardt
<craigm...@REMOVEcow.physics.wisc.edu> wrote:
> d.po...@gmail.com writes:
>> On Jul 31, 1:21 pm, Wox <nom...@hotmail.com> wrote:
>>> On Thu, 31 Jul 2008 03:30:22 -0700 (PDT), d.po...@gmail.com wrote:
>>>> Folks
>>>> How we can do the piecewise curve fitting in idl. Say we have an array
>>>> that this array has got 2 or 3 trends in data and we want to fit a
>>>> liner curve for each trends. In MATLAB curve fitting tool, we can
>>>> easily exclude or include a part of data and then fit a curve. How we
>>>> can do this in IDL
>>>> Cheers
>>>> Dave
>
>>> Euhm, just do the fitting on the different parts? Or do you mean
>>> fitting with a piecewise polynomial (i.e. spline: see e.g. IMSL_BSLSQ
>>> or IMSL_CONLSQ)
>
>> just doing the fitting on the difrent part. how we can select this
>> parts and how we can fit a curve to these parts separatly?
>
> I realize I'm coming into this discussion late. However, the IDL
> Astronomy library has a nice procedure LINTERP which would be very
> useful for an application like this. It would still need to be
> interfaced to a fitting function. It would allow you to fit the
> tabulated Y values, and in principle even the tabulated-X positions,
> although I would NOT advise that.
>
> For a graphical interface, IDL is probably not the best application
> unless you want to write the whole program yourself.
>
> Craig
>
> --
> ------------------------------------------------------------ --------------
> Craig B. Markwardt, Ph.D. EMAIL: craigm...@REMOVEcow.physics.wisc.edu
> Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
> ------------------------------------------------------------ --------------
could you please send me the Astronomy library link for this.
Cheers
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