15,421 reputation
13189
bio website quantdec.com
location Northeastern US
age 14
visits member for 3 years
seen Jan 23 at 23:34

Consultant (environmental and spatial stats a specialty), expert witness, and teacher. I can be reached through (outdated but still valid) links posted on my web site.

Twitter: @WilliamAHuber // ASA-P website: http://amstatphilly.org/


Why waste time learning, when ignorance is instantaneous?

--T(iger) Hobbes.

For any complex problem there is a simple solution. And it's always wrong.

--[Mis?]attributed to H.L. Mencken by Dava Sobel, Longitude.


Dec
26
answered Define Log so that negative reals evaluate on lower edge of branch
Dec
24
revised How do I solve this equation?
Removed a potentially deceptive term from the title (this is not a functional equation).
Dec
21
comment Can Depth be used as an equivalent for MatrixQ?
@jVincent I do not know why you are addressing that last comment to me: I have not written anything here about lack of knowledge, intuition, FullForm, f[x_], or anything else you mention, nor have I ever suggested that the status of this question should be resolved based on our guesses about the O.P.'s state of mind. I have explained why I think this question, based on its merits, needs improvement, without resorting to any speculation about the knowledge or background of the person who asked it. (And--unlike 7 other people--I have not downvoted it.)
Dec
21
reviewed Leave Closed Can Depth be used as an equivalent for MatrixQ?
Dec
21
comment Creating an animation illustrating the time-evolution of a pre-computed orbit
+1 The tube is a great idea for giving a 3D visual cue.
Dec
21
comment Can Depth be used as an equivalent for MatrixQ?
I appreciate your comment, @jVincent. I would vote to reopen if the O.P. would at least explain what they think each expression is supposed to be doing. Without that, I maintain there is no question here except as each reader individually chooses to imagine it. Your personal construction of the question, as reflected in your answer, is reasonable, but whether it is a unique interpretation or the intended interpretation is difficult to determine.
Dec
21
comment An recurrence equation that can be solved in version 7 but not in version 8
It is interesting that the same problem, with $5$ changed to $4$, is solved in less than $0.1$ seconds with MMA 8, and with $5$ changed to $7$, the solution also takes less than $0.1$ seconds (although it's trivially expressed in terms of DifferenceRoot, which is just another way of giving up). With $5$ changed to $6$, a useful solution is obtained in $6$ seconds.
Dec
21
comment Can Depth be used as an equivalent for MatrixQ?
I confess to being mystified by this question. First, what is a "phrase," exactly? Second, if we take these to be Mathematica expressions, it is obvious they do completely different things, leaving me wondering what you might mean by "interchangeable." I am voting to close this as a non-question.
Dec
21
awarded  Nice Answer
Dec
20
comment How to calculate this sum?
There is a story, well known to mathematicians, about a very young Karl Gauss being set the problem of summing $1+2+\cdots+100$. He obtained the solution almost immediately by observing that by taking the sum from both ends, it "folds" into $(1+100)+(2+99)+\cdots+(49+52)+(50+51)$ = $101+101+\cdots+101$ = $50\times 101$. Summing $f(i/n)$ is accomplished with the same idea.
Dec
20
comment How to find lattice points on a line segment?
Nice idea. Incidentally, I noticed, in editing the question, that it stipulates the solutions should have positive coordinates.
Dec
20
revised How to find lattice points on a line segment?
deleted 1 characters in body; edited title
Dec
20
answered How to calculate this sum?
Dec
20
reviewed Close Function with different set of arguments
Dec
19
reviewed Close How to pass arguments between functions
Dec
18
reviewed Close Deformed style when exporting eps files
Dec
18
awarded  Good Answer
Dec
18
comment Edges and crossing
I wonder what crossing "over" and crossing "under" mean: how do you tell?
Dec
17
comment About extension fibonacci
The final expression needs some modifications to be correct: it must compute modulo $10$ (the length of the cycle) rather than modulo $9$ and it must offset the result by $1$, because MMA will complain when you try to index that list with a zero.
Dec
17
comment About extension fibonacci
For the purpose of identifying the $n$th *digit* in these "Fibonacci strings"--rather than just the $n$th step of their generation--it would be more convenient to represent the cycles slightly differently; namely, as $(14,45,59,91)$ and $(11,12,23,35,58,81,13,34,47,71)$.