Re: [Scilab-users] 3D interpolation : comments adding
linear_interpn(repetitus, repetita, repetitum) = repeated -- View this message in context: http://mailinglists.scilab.org/Scilab-users-3D-interpolation-comments-adding-tp4035998p4036009.html Sent from the Scilab users - Mailing Lists Archives mailing list archive at Nabble.com. ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation : comments adding
Le 25/03/2017 à 19:38, paul.carr...@free.fr a écrit : Hi Tim That's indeed what I've read as well; my need remains to get a linear interpolation between physical points ... I'm still digging in order to find a "pleasant" code :_) linear_interpn() is made for that: https://help.scilab.org/docs/6.0.0/en_US/linear_interpn.html Samuel ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation : comments adding
Hi Tim
That's indeed what I've read as well; my need remains to get a linear
interpolation between physical points ... I'm still digging in order to
find a "pleasant" code :_)
Thanks for the feedback
Paul
Le 2017-03-25 17:52, t...@wescottdesign.com a écrit :
> The help says that splin2d generates bicubic patches, so presumably
> it's not linear interpolation.
>
> On 2017-03-25 00:24, paul.carr...@free.fr wrote:
>
>> Hi All
>>
>> To go further in 2D/3D interpolation as I started in my previous
>> emails, I built the example here after.
>>
>> As suggested, I had a look to
>> - cshep2d but but seems can not be used here (dimensions issue)
>> - splin2d + interp2d
>>
>> In the later case, Am I right to say that splin2d "cross-sections"
>> the surface in order to define the "best spline" passing through the
>> nodes (in the cross section obviously), then the
>> interpolation/calculation is basically using this new 2D function,
>> right ?
>>
>> if so this is not a linear interpolation between 2 nodes (as I
>> expect), isn't it?
>>
>> Paul
>>
>>
>>
>> mode(0)
>>
>> n=10;
>> x = linspace(0,300,(n+1))';// abscissa
>> t = [0 25 100]; // temperature
>> z = 20*rand((n+1),3);// ordinate
>> // Nota : we must have the same number of data for both x and z
>>
>> // plot3d
>> clf()
>> a=get("current_axes");
>> a.x_label; x_label=a.x_label; x_label.text=" X abscissa";
>> a.y_label; y_label=a.y_label; y_label.text=" Temperature T";
>> a.z_label; z_label=a.z_label; z_label.text=" y ordinate";
>> plot3d(x,t,z)
>>
>> // Nota: if I do a cross section normal to XoZ plane, I've the basic
>> curve z=f(x,T)) -> seems correct
>>
>> // interpolation
>> xp = [22 103 236]'
>> tp = [5 56 85]'
>>
>> [Xp,Tp] = ndgrid(xp,tp)
>>
>> ___
>> users mailing list
>> users@lists.scilab.org
>> http://lists.scilab.org/mailman/listinfo/users
> ___
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> users@lists.scilab.org
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Re: [Scilab-users] 3D interpolation : comments adding
The help says that splin2d generates bicubic patches, so presumably it's
not linear interpolation.
On 2017-03-25 00:24, paul.carr...@free.fr wrote:
> Hi All
>
> To go further in 2D/3D interpolation as I started in my previous emails, I
> built the example here after.
>
> As suggested, I had a look to
> - cshep2d but but seems can not be used here (dimensions issue)
> - splin2d + interp2d
>
> In the later case, Am I right to say that splin2d "cross-sections" the
> surface in order to define the "best spline" passing through the nodes (in
> the cross section obviously), then the interpolation/calculation is basically
> using this new 2D function, right ?
>
> if so this is not a linear interpolation between 2 nodes (as I expect), isn't
> it?
>
> Paul
>
>
>
> mode(0)
>
> n=10;
> x = linspace(0,300,(n+1))';// abscissa
> t = [0 25 100]; // temperature
> z = 20*rand((n+1),3);// ordinate
> // Nota : we must have the same number of data for both x and z
>
> // plot3d
> clf()
> a=get("current_axes");
> a.x_label; x_label=a.x_label; x_label.text=" X abscissa";
> a.y_label; y_label=a.y_label; y_label.text=" Temperature T";
> a.z_label; z_label=a.z_label; z_label.text=" y ordinate";
> plot3d(x,t,z)
>
> // Nota: if I do a cross section normal to XoZ plane, I've the basic curve
> z=f(x,T)) -> seems correct
>
> // interpolation
> xp = [22 103 236]'
> tp = [5 56 85]'
>
> [Xp,Tp] = ndgrid(xp,tp)
>
> ___
> users mailing list
> users@lists.scilab.org
> http://lists.scilab.org/mailman/listinfo/users___
users mailing list
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Re: [Scilab-users] 3D interpolation : comments adding
Try this:
n=21;
x = linspace(0,300,n)';// abscissa
t = [0 25 100];// temperature
z = n*sin(x/n).*.cos(t/n); // ordinate
clf()
a=get("current_axes");
a.x_label.text=" X abscissa";
a.y_label.text=" Temperature T";
a.z_label.text=" Z ordinate";
// linear interpolation
xp = [22 103 236];
tp = [5 56 85];
[Xp,Tp] = ndgrid(xp,tp);
Zp = linear_interpn(Xp,Tp, x, t, z);
plot3d(x,t,z)
// requires Scilab-6 for scatter plot:
scatter3(Xp(:), Tp(:), Zp(:), "markerEdgeColor", "black","markerFaceColor",
[.9 .3 .0])
Rgds,
Rafael
<http://mailinglists.scilab.org/file/n4036001/3D_linear_interpolation.png>
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[Scilab-users] 3D interpolation : comments adding
Hi All
To go further in 2D/3D interpolation as I started in my previous emails,
I built the example here after.
As suggested, I had a look to
- cshep2d but but seems can not be used here (dimensions issue)
- splin2d + interp2d
In the later case, Am I right to say that splin2d "cross-sections" the
surface in order to define the "best spline" passing through the nodes
(in the cross section obviously), then the interpolation/calculation is
basically using this new 2D function, right ?
if so this is not a linear interpolation between 2 nodes (as I expect),
isn't it?
Paul
mode(0)
n=10;
x = linspace(0,300,(n+1))';// abscissa
t = [0 25 100]; // temperature
z = 20*rand((n+1),3);// ordinate
// Nota : we must have the same number of data for both x and z
// plot3d
clf()
a=get("current_axes");
a.x_label; x_label=a.x_label; x_label.text=" X abscissa";
a.y_label; y_label=a.y_label; y_label.text=" Temperature T";
a.z_label; z_label=a.z_label; z_label.text=" y ordinate";
plot3d(x,t,z)
// Nota: if I do a cross section normal to XoZ plane, I've the basic
curve z=f(x,T)) -> seems correct
// interpolation
xp = [22 103 236]'
tp = [5 56 85]'
[Xp,Tp] = ndgrid(xp,tp)___
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Re: [Scilab-users] 3D interpolation
thanks all for the answers; I didn't know about ndgrid and I'm currently having a look on it (seems to be quite interesting) Samuel: from your example and the help doc, I need to understand how to proceed to perform linear interpolations (temperatures and abscissa's in my example) Paul Le 2017-03-24 21:40, Samuel Gougeon a écrit : > Le 24/03/2017 à 18:40, paul.carr...@free.fr a écrit : > >> Hi all, >> >> I don't know if my question is relavante (or not), but I'm wondering >> what is the best way to perform a 3D interpolation, from for the >> matrix definition to the interpolation procedure. >> >> Let me using a basic example: I've some curves y = f(x,T) defining a >> material behaviour at different temperatures i.e. 1 curve (x,y) per >> temperature: >> - y = f(x,20) >> - y = f(x,100) >> - y = f(x,200) >> >> etc. >> >> What is the best way to define a single matrix? [x y T] ? > > It depends on whether f() is vectorized or not. It could be something > like > t = [20 100 200]; > [X, T] = ndgrid(x, t); > Y = f(X,T); > // or > Y = feval(x, t); > > Then: > M = [X(:) Y(:) T(:)]; > ___ > users mailing list > users@lists.scilab.org > http://lists.scilab.org/mailman/listinfo/users___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation
Le 24/03/2017 à 18:40, paul.carr...@free.fr a écrit : Hi all, I don't know if my question is relavante (or not), but I'm wondering what is the best way to perform a 3D interpolation, from for the matrix definition to the interpolation procedure. Let me using a basic example: I've some curves y = f(x,T) defining a material behaviour at different temperatures i.e. 1 curve (x,y) per temperature: - y = f(x,20) - y = f(x,100) - y = f(x,200) etc. What is the best way to define a single matrix? [x y T] ? It depends on whether f() is vectorized or not. It could be something like t = [20 100 200]; [X, T] = ndgrid(x, t); Y = f(X,T); // or Y = feval(x, t); Then: M = [X(:) Y(:) T(:)]; ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation
That doesn't show up in the help for 5.5.2. Is it a 6.x thing, or is there a toolbox? Looks interesting, at any rate. On Fri, 2017-03-24 at 18:45 +0100, CRETE Denis wrote: > Hello ! > Did you try cshep2d + eval_cshep2d ? > HTH > Denis > > [@@ THALES GROUP INTERNAL @@] > > Unité Mixte de Physique CNRS / THALES > 1 Avenue Augustin Fresnel > 91767 Palaiseau CEDEx - France > Tel : +33 (0)1 69 41 58 52 Fax : +33 (0)1 69 41 58 78 > e-mail : > denis.cr...@thalesgroup.com <mailto:%20denis.cr...@thalesgroup.com> > http://www.trt.thalesgroup.com/ump-cnrs-thales > http://www.research.thalesgroup.com > > De : users [mailto:users-boun...@lists.scilab.org] De la part de paul > .carr...@free.fr > Envoyé : vendredi 24 mars 2017 18:41 > À : User Scilab > Objet : [Scilab-users] 3D interpolation > > Hi all, > > I don't know if my question is relavante (or not), but I'm wondering > what is the best way to perform a 3D interpolation, from for the > matrix definition to the interpolation procedure. > > Let me using a basic example: I've some curves y = f(x,T) defining a > material behaviour at different temperatures i.e. 1 curve (x,y) per > temperature: > - y = f(x,20) > - y = f(x,100) > - y = f(x,200) > > etc. > > What is the best way to define a single matrix? [x y T] ? > > > Next step is to be able to perform a 3D interpolation whatever is the > temperature (for a given x) ... any advice? (of course I'm looking to > interp3D flag. > > Thanks for any feedback > > Paul > ___ > users mailing list > users@lists.scilab.org > http://lists.scilab.org/mailman/listinfo/users -- Tim Wescott www.wescottdesign.com Control & Communications systems, circuit & software design. Phone: 503.631.7815 Cell: 503.349.8432 ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation
I'm not an expert. But: I did a quick spin through the help files and came up with splin2d and interp2d. It looks like what you want -- get the splines in x and T using splin2d, and find the y values for a given x and T using interp2d. I don't know if this is the very best way to do this mathematically -- I know that this sort of 2D interpolated look-up is used extensively in engine management units in cars (they're called "maps" in that lingo), so there's probably a lot of research on accuracy vs. efficiency tradeoffs. On Fri, 2017-03-24 at 18:40 +0100, paul.carr...@free.fr wrote: > Hi all, > > I don't know if my question is relavante (or not), but I'm wondering > what is the best way to perform a 3D interpolation, from for the > matrix definition to the interpolation procedure. > > Let me using a basic example: I've some curves y = f(x,T) defining a > material behaviour at different temperatures i.e. 1 curve (x,y) per > temperature: > - y = f(x,20) > - y = f(x,100) > - y = f(x,200) > > etc. > > What is the best way to define a single matrix? [x y T] ? > > > Next step is to be able to perform a 3D interpolation whatever is the > temperature (for a given x) ... any advice? (of course I'm looking to > interp3D flag. > > Thanks for any feedback > > Paul > ___ > users mailing list > users@lists.scilab.org > http://lists.scilab.org/mailman/listinfo/users -- Tim Wescott www.wescottdesign.com Control & Communications systems, circuit & software design. Phone: 503.631.7815 Cell: 503.349.8432 ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3D interpolation
Hello ! Did you try cshep2d + eval_cshep2d ? HTH Denis [@@ THALES GROUP INTERNAL @@] Unité Mixte de Physique CNRS / THALES 1 Avenue Augustin Fresnel 91767 Palaiseau CEDEx - France Tel : +33 (0)1 69 41 58 52 Fax : +33 (0)1 69 41 58 78 e-mail : denis.cr...@thalesgroup.com<mailto:denis.cr...@thalesgroup.com> <mailto:%20denis.cr...@thalesgroup.com> http://www.trt.thalesgroup.com/ump-cnrs-thales http://www.research.thalesgroup.com De : users [mailto:users-boun...@lists.scilab.org] De la part de paul.carr...@free.fr Envoyé : vendredi 24 mars 2017 18:41 À : User Scilab Objet : [Scilab-users] 3D interpolation Hi all, I don't know if my question is relavante (or not), but I'm wondering what is the best way to perform a 3D interpolation, from for the matrix definition to the interpolation procedure. Let me using a basic example: I've some curves y = f(x,T) defining a material behaviour at different temperatures i.e. 1 curve (x,y) per temperature: - y = f(x,20) - y = f(x,100) - y = f(x,200) etc. What is the best way to define a single matrix? [x y T] ? Next step is to be able to perform a 3D interpolation whatever is the temperature (for a given x) ... any advice? (of course I'm looking to interp3D flag. Thanks for any feedback Paul ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
[Scilab-users] 3D interpolation
Hi all, I don't know if my question is relavante (or not), but I'm wondering what is the best way to perform a 3D interpolation, from for the matrix definition to the interpolation procedure. Let me using a basic example: I've some curves y = f(x,T) defining a material behaviour at different temperatures i.e. 1 curve (x,y) per temperature: - y = f(x,20) - y = f(x,100) - y = f(x,200) etc. What is the best way to define a single matrix? [x y T] ? Next step is to be able to perform a 3D interpolation whatever is the temperature (for a given x) ... any advice? (of course I'm looking to INTERP3D flag. Thanks for any feedback Paul___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
Re: [Scilab-users] 3d interpolation griddata
Hello, the cshep2d macro should fit your needs. S. Le 12/11/2014 22:40, simond a écrit : Hi, I am trying to convert a matlab code using griddata. Unfortunately, I havent succeed to solve the problem with the available scilal functions (linear_interpn, interpd..). I have a data set of disordered points (x,y,z), with x,y the position, and z the elevation. I m trying to interpolate all this points to create a 3d digital elevation model. 1) I create a meshgrid xx=min(x):1:max(x) yy=min(y):1:max(y) [xy,yx]=meshgrid(xx,yy) 2) I would like to interpolate all the elevation points z for my new grid (xy,yx) such as xy,yx,zz=griddata(x,y,z,xy,yx) But i cannot find the scilab equivalence... Thank you very much for your response. Simon -- View this message in context: http://mailinglists.scilab.org/3d-interpolation-griddata-tp4031468.html Sent from the Scilab users - Mailing Lists Archives mailing list archive at Nabble.com. ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
[Scilab-users] 3d interpolation griddata
Hi, I am trying to convert a matlab code using griddata. Unfortunately, I havent succeed to solve the problem with the available scilal functions (linear_interpn, interpd..). I have a data set of disordered points (x,y,z), with x,y the position, and z the elevation. I m trying to interpolate all this points to create a 3d digital elevation model. 1) I create a meshgrid xx=min(x):1:max(x) yy=min(y):1:max(y) [xy,yx]=meshgrid(xx,yy) 2) I would like to interpolate all the elevation points z for my new grid (xy,yx) such as xy,yx,zz=griddata(x,y,z,xy,yx) But i cannot find the scilab equivalence... Thank you very much for your response. Simon -- View this message in context: http://mailinglists.scilab.org/3d-interpolation-griddata-tp4031468.html Sent from the Scilab users - Mailing Lists Archives mailing list archive at Nabble.com. ___ users mailing list users@lists.scilab.org http://lists.scilab.org/mailman/listinfo/users
