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seen Sep 29 '13 at 16:54

Feb
19
comment Interpolating 2D data with missing values
When I use the method above to do interpolation, I get errors: Unstructured grid interpolation order reduced to 1 and coerced to machine precision. In version 9, it seems to do it but when running the code in version 7, I get an error message and stops. Can you please help me in finding out how to interpolate unstructured data properly?
Feb
5
comment Interpolating 2D data
,Can you please suggest how can I replace the zero with mean of surrounding values. It's a good idea, but is there any function to do that? Can interpolation function be tweaked to do it? Thanks
Feb
1
comment Interpolating 2D data with missing values
that's a very good remark. Thanks for that. I'll have a look at it
Feb
1
comment Interpolating 2D data with missing values
thanks for the answer. I have one slight issue. When I remove the zeros and interpolate, I get some errors; More precisely: if for example the position {1,1} had a zero, I get an error message saying "{1,1} cannot be interpolated, so extrapolation is used" And I get a fairly higher value than the surroundings. Also after a few of these errors, it says "Interpolation output suppressed". Any idea how to fix that?
Feb
1
comment Interpolating 2D data
many thanks for the answer. It works fine. However, some of the interpolated values are sometimes very different to its surrounding values. And I would like to know to smooth out all the values in the array? Any ideas. Thanks!
Jan
22
comment Interpolating 2D data with missing values
@belisarius ListInterpolation allows me to input an array of values from which it interpolates the data. But is there a way of interpolating the data based on the nearest values? the top, bottom, side values? Thank you
Jan
22
comment Interpolating 2D data with missing values
@belisarius I tried using ListInterpolation, using the list as parameter, but doesn't work.. comes up with error
Jan
21
comment Add noise (random values) to data
@belisarius, I just realised you made some changes to the code you quoted above. This works fine too. Thanks!
Jan
21
comment Add noise (random values) to data
Yea..Kguler, that does it. Thanks a lot!
Jan
21
comment Add noise (random values) to data
maybe a function that add some random values to each point?
Jan
21
comment Add noise (random values) to data
Ahh sorry.. the above code gives me 3 points = (x,y,z) and I want to add noise to x,y,z, that is some random values (range 0 - 5) to x,y,z
Jan
17
comment Optimising 2D binning code
@OleksandrR. Sorry I don't quite understand your comment. Gwyddion gave a set of 100x100 z values (all real values) while the code above returned lots of zeros. Is it to do with my bin intervals? I did (max - min)/100 to calculate the interval
Jan
16
comment Optimising 2D binning code
@Mr.Wizard, i tried your codes and ran it with my data. I tried with 10,000 data and 100x100 bins. The final array of z values has a lot of zeros (implying empty bins). I ran the same data using the software Gwyddion which binned the data and returned 100x100 z values without a single zero in the array. Is there anything wrong with the code above? Thank you
Jan
15
comment Optimising 2D binning code
@kguler thank you
Jan
15
comment Optimising 2D binning code
Does it set the SparseArray function back to normal?
Jan
15
comment Optimising 2D binning code
@kguler, I understand that you overloaded the SparseArray function to calculate mean of the repeated entries in the bin.. But what does the last command do ? System`SetSystemOptions["SparseArrayOptions" -> {"TreatRepeatedEntries" -> First}];
Jan
15
comment Optimising 2D binning code
@kguler Can you please tell me how the indexes are calculated? i mean how is it similar to binLists?
Jan
15
comment Optimising 2D binning code
Or where should I use BinLists in this code?
Jan
15
comment Optimising 2D binning code
And is the final result average of binned z values?
Jan
14
comment Optimising 2D binning code
@kguler and @ Mr.Wizard, thanks for the quick responses. It looks good but one the possible problem with this rescaling method is that it can round 2 different values to 1 value.And this will introduce error in my final result. My original data are decimal real values and accuracy is important. Is there any other way of doing it by not using Rescale ? Thank you