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bio website nl.linkedin.com/in/scdevries
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visits member for 2 years, 9 months
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23h
comment Randomly changing matrix entries
RandomSample. DeleteCases.
1d
comment Non linear model fit
Undefined function wlog? wlog= w Log? Space between k and c in kc?
1d
comment How should I provide Dataset slot names in function definitions?
The function as you defined it here works for me... I think you have an old definition using #s (see error message) instead of #[s] (function definition). Use ClearAll[f] and try again.
2d
comment NIntegrate on tetrahedron
Given that the message text is missing this looks like a case for Wolfram support (support@wolfram.com).
2d
comment NIntegrate on tetrahedron
Are you sure you copied the message tag correctly? I can't find the corresponding message text. Also, could you provide a bit of your code?
Oct
27
comment Derivatives of functions with arbitrary number of variables?
This may be related to or perhaps is a duplicate of symbolic-derivative-of-n-term-product.
Oct
27
comment Speeding up the non-negativity algorithm for multilinear function with interval probabilities?
Voted to close your own question? Strange remark; you could have deleted it any time you wanted.
Oct
26
comment C compilation not working with Visual Studio 2013
@JoseECalderon Right click the file, then Properties -> Security tab -> Edit Permissions Users -> allow Modify
Oct
26
comment C compilation not working with Visual Studio 2013
@@bbgodfrey. OK, a restart of my laptop did the trick.
Oct
26
comment C compilation not working with Visual Studio 2013
@bbgodfrey. I have exactly the same configuration, but it doesn't work for me. I did run VS 2013 as you wrote, but no fun so far. Any ideas?
Oct
26
comment Findfit doesn't provide reasonable results when fitting a complex function
Have a look at NonlinearModelFit.
Oct
26
comment Findfit doesn't provide reasonable results when fitting a complex function
It looks like Mathematica's fit is just fine and you're mistaken about the optimal value. You can confirm that using Manipulate[ Show[ ListPlot[data], Plot[f[a, b, x], {x, 8, 50}] ], {{a, 160}, 20, 400}, {{b, 186}, 20, 400} ]. Note that I followed my own advice and used Set in the definition of f here, and also removed r_ in the definition.
Oct
26
comment Findfit doesn't provide reasonable results when fitting a complex function
Try defining f using Set (=) instead of SetDelayed (:=). In the latter case the integral is only evaluated after filling in your machine precision numbers, and evaluation is done only with machine precision. If you use Set, the integral is evaluated symbolically and assigned to f. If you then use f the results are much more accurate. I get f[160.339, 186.173, 8.5] = 0.851972. BTW You define f with a fourth parameter r which doesn't make sense, as it will be gone in the right hand side after the integration.
Oct
23
comment Is this an error/bug with Plot Command?
Probably duplicate of this or this. Related: plotting-complex-quantity-functions.
Oct
23
comment Visualization of 3D data by Raster3D and Import
My point was that you can't use Raster3D[Import["data.txt"] ] as you said you wanted but that you have to do 'imp=Import[something]; impPar=Partition[imp,...];Raster3D[impPar]'. You need an intermediate step. Partition can work there.
Oct
23
comment How to find out the current memory on the JVM?
Just a warning about freememory (it's not really the total available amount), see here.
Oct
21
comment Open a .txt file in Mathematica
There ain't such thing as a ".txt file written for Mathematica".
Oct
18
comment Unexpected behavior from Indexed
Interesting. I managed to fully miss this function's introduction.
Oct
18
comment Concisely returning a position in an array with an index variable
@Mr.Wizard Really? That would surprise me ;-)
Oct
18
comment Concisely returning a position in an array with an index variable
@Mr.Wizard OK, but perhaps you should have provided that link in your earlier comment.