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| How can I do scatered data interpolation using alglib http://forum.alglib.net/viewtopic.php?f=2&t=137 |
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| Author: | arunbaruah [ Tue Dec 07, 2010 5:23 am ] |
| Post subject: | How can I do scatered data interpolation using alglib |
Hi, I am new to alglib. I want to do cubic interpolation on scattered data. Please guide me how to do 1 Dimensional, 2 dimensional and 3 dimensional cubic spline interpolation using alglib. Thank you, Regards, Arun |
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| Author: | Sergey.Bochkanov [ Tue Dec 07, 2010 8:09 am ] |
| Post subject: | Re: How can I do scatered data interpolation using alglib |
You can use spline1d subpackage for 1-dimensional spline interpolation. As for 2-dimensional splines, only interpolation on regular grid is supported. If you need scattered multidimensional fitting, you can try http://www.alglib.net/interpolation/inv ... ghting.php - it is hard to tune, but sometimes gives good results. |
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| Author: | arunbaruah [ Tue Dec 14, 2010 6:23 am ] |
| Post subject: | Re: How can I do scatered data interpolation using alglib |
Thank you Sergey. I tried 1 d spline, but do not know how do I solve the 2 and 3 d. It is because I am totally new in interpolation, I understand that spline interpolation is to find an unknown value between x & y, but really do not know how to solve it in computer. Please help me in the below code: public void spline2d_cubicExample() { double[] x = new double[] { 1980, 1990, 2000, 2010, 2020 }; double[] y = new double[] { 50, 100, 175, 200, 240 }; double[,] f; //what to do with this field? I am simply trying to pass it to the function below, //but do not know the purpose double findAtThisValue = 2012; double interpolatedValue; //instantiate the spline2d interpolant alglib.spline2dinterpolant spline; //build 2 dim cubic spline interpolant alglib.spline2d.spline2dbuildbicubic(x, y, ref f, x.Length, y.Length, spline); //getting compile error } //I am stuck here, if I know what is in the third parameter i.e., f then propably I could solve. Please help me. Thank you Arun |
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| Author: | arunbaruah [ Wed Dec 29, 2010 12:40 pm ] |
| Post subject: | How can I do scatered data interpolation using alglib? |
Hi, Can any one help me how to use the alglib for 2D and 3D cubic spline interpolation? I am very new in alglib as well as to methematics. Thanks in advance Arun |
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| Author: | Sergey.Bochkanov [ Thu Dec 30, 2010 6:34 pm ] |
| Post subject: | Re: How can I do scatered data interpolation using alglib |
As for 2D interpolation, you should fill f with values of function on a regular grid. 3D interpolation with cubic splines is not supported by ALGLIB. |
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