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| bio | website | quantdec.com |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 4 months |
| seen | yesterday | |
| stats | profile views | 911 |
Consultant (environmental stats a specialty) and teacher.
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Jan 16 |
comment |
Plotting discrete data but not using discreteplot function Thank you for changing those erroneous values--although the integrands are now incorrect, because they omit most of the function. (However, I do not understand why you need "manual computation" when you have already exhibited a valid Mathematica formula for computing the $a_n$.) I also do not understand what you mean by a "continuous" graph to "contain" these discrete values. An example or a sketch might help convey your intentions. |
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Jan 16 |
comment |
Plotting discrete data but not using discreteplot function All the integrals you list for $n=1,2,\ldots,5$ are zero: you seem to be displaying some kind of floating point error. They are not relevant to the $a_n$ anyway. So what really is your question? |
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Jan 16 |
comment |
Creating a Specific Boolean Function +1 This makes me smile--it's always fun to see how you can reconstruct something with such brevity. |
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Jan 16 |
comment |
LinearModelFit with millions of rows I have not found any option in LinearModelFit to delay those calculations. Fortunately, all the ancillary calculations are easy to carry out--it's just a bit of a pain. But any regression with millions of data points is going to take some work :-). (I suppose in MMA 9 you could link to R and use its lm, summary, predict, etc. functions.) |
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Jan 16 |
revised |
Creating a Specific Boolean Function added 76 characters in body |
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Jan 16 |
revised |
Creating a Specific Boolean Function added 466 characters in body |
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Jan 16 |
answered | Creating a Specific Boolean Function |
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Jan 16 |
revised |
LinearModelFit with millions of rows added 24 characters in body |
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Jan 16 |
comment |
Graph a Function with general conditions There would be no harm in including both solutions in your answer :-). |
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Jan 15 |
answered | LinearModelFit with millions of rows |
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Jan 15 |
comment |
Exporting 3D ploted figure complete with legend ready for Word This appears to cover exactly the same ground as your previous question at mathematica.stackexchange.com/questions/17706/… |
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Jan 15 |
comment |
Graph a Function with general conditions Cleaner and (far) more efficient is f[x_] := Sqrt[Abs[Mod[x, 2 Pi, -Pi]]], because if there is any possibility f would be applied to largish numbers, the recursive solution doesn't work. (E.g, try Plot[f[x], {x, 10^6 - 20, 10^6}].) |
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Jan 15 |
comment |
Help for double parametrized integration: algebraic vs Mathematica solutions Your integral is much simpler than it appears, so consider re-expressing it. $y$ is piecewise constant, whence so are $y(s)^2ds$, whence its integral, whence its exponential, whence the entire integrand, because $u$ also is piecewise constant. Therefore, what you are trying to integrate is a sum of constants! This suggests you change your approach into characterizing the regions at which the value of the integrand changes; within each region, the value is trivial to compute. MMA is struggling with managing all possible orderings of $t_1$ relative to $t,\delta,0,1$, etc. |
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Jan 15 |
revised |
Efficiently extracting an array subset given a separate array added 12 characters in body |
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Jan 15 |
answered | Efficiently extracting an array subset given a separate array |
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Jan 15 |
reviewed | Leave Open Use of Mathematica to generate report |
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Jan 14 |
reviewed | Reviewed Problem with NIntegrate in NonlinearModelFit |
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Jan 14 |
reviewed | Leave Closed Is it possible to use PatternTest and Optional value on one Pattern simultaneously? |
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Jan 14 |
comment |
Ways to compute inner products of tensors From the tutorial on tensors: "You can think of Inner as performing a "contraction" of the last index of one tensor with the first index of another. If you want to perform contractions across other pairs of indices, you can do so by first transposing the appropriate indices into the first or last position, then applying Inner, and then transposing the result back." For multiple contractions, as in the second example, transpose all involved indexes to the end, Flatten them into a single index, and then perform a contraction. |
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Jan 14 |
revised |
How find the first element of a list greater than zero (or another criterion) when there is a symbol in the list? spelling |
