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visits member for 2 years, 7 months
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I'm a retired mathematics professor who's used numerous programming languages over the years, including FORTRAN, Pascal, and APL. My current programming interests are Mathematica and J (the jsoftware.com free product), both of which I've used in teaching.


Aug
25
comment Counting the zeros in a factorial expansion
Indeed, First@Timing@Count[IntegerDigits[1000!], 0] gives 0.000198 whereas First@Timing@countZeros[1000] gives 0.000157. Moreover, on my system, First@Timing@Count[IntegerDigits[10000!], 0] give 0.003858 whereas First@Timing@countZeros[10000] gives 0.002740.
Aug
22
comment Is Mathematica an Implementation of the Wolfram Language?
The answer does not seem to be quite accurate. "The Wolfram Language" is not a new name for Mathematica. Rather, The Wolfram Language is a language that is implemented in the product Mathematica. But it is also implemented in other Wolfram Research products.
Aug
14
answered Error with “Newton's method” in Wellin's Mathematica book
Aug
14
comment Error with “Newton's method” in Wellin's Mathematica book
In timing results, why did you switch to initial approximation of 0.1 whereas the various methods preceding that all started at 2.0?
Aug
14
comment Error with “Newton's method” in Wellin's Mathematica book
There's something deeper wrong with the proffered code: the stopping criterion is that the magnitude of $f$ at the current approximation $x_i$ be sufficiently small. But such $x_i$ might be quite far from the desired root if the graph of $f$ is flat near there. One should substitute, or append, a rule that $|x_i - x_{i-1}|$ be sufficiently small.
Aug
8
answered Why is this Mandelbrot set's implementation infeasible: takes a massive amount of time to do?
Aug
8
comment Are there tools for getting Mathematica 9 Notebooks working in Mathematica 10?
Sorry, I meant PlotTheme -> "Classic".
Aug
8
comment Are there tools for getting Mathematica 9 Notebooks working in Mathematica 10?
For plots, did you try including option PlotTheme -> None?
Aug
3
comment Integral with unreliable result
Is this a mathematics question or a Mathematica question? If the former, move to another forum. If the latter, please paste actual Mathematica code.
Aug
3
comment Is there a function that, given a fraction, will return the general term of its infinite series expansion?
@Henry: do you mean "rational function" (or even just "function") rather than "fraction"?
Aug
3
comment V10's Operator Forms - what are they good for?
Related: mathematica.stackexchange.com/questions/51628/…
Aug
2
comment Finding unit tangent, normal, and binormal vectors for a given r(t)
The new FrenetSerretSystem perfectly illustrates how adding certain higher-level functions to Mathematica in part impedes the pedagogical opportunity to learn such higher-level mathematical constructs by building them up from lower-level ones. (Of course one may still "simulate" such a function by building it up.) Another, much older example: RowReduce.
Jul
28
comment Cheat sheets or reference cards for Mathematica
Don't forget the utility of the Classroom Assistant palette! (Even though it doesn't provide a printable page, it's right there with a mouse click or two while you're using Mathematica.)
Jul
28
comment Check for holomorphy of a function
Satisfying the Cauchy-Riemann equations does not suffice to make a function holomorphic! Simple example: f[z_] := Conjugate[z]^2/z, f[0] = 0; this is not differentiable at the origin, although it does satisfy the C-R equations there.
Jul
28
comment Is there a function for nearest power of 2 in Mathematica like nextpow2 in MATLAB?
Re "v10 syntax": is it just the shortcut notation @* that was added in Mathematica 10*? Note that Composition dates to version 2.0.
Jul
28
comment Intersection of lists of disjoint intervals
Do you want the intersections of each of the intervals in the first list with each of the intervals in the second list? (Presumably you do not want intersections of corresponding entries in each of the two lists, since in the example your lists have different lengths.)
Jul
24
comment Is there a way to recreate the typical Red/Blue-Postereffect using Mathematica?
+1 for choice of image!
Jul
24
comment Computational complexity of symbolic determinant
Documentation Center page tutorial/SomeNotesOnInternalImplementation#7441 says, "Det uses direct cofactor expansion for small matrices and Gaussian elimination for larger ones."
Jul
24
comment Mathematica 10 : Where is the Mathematica Book?
Same thing is in the in-application tutorial/VirtualBookOverview. But how can one add a link to this on the Mathematica 10 Help menu or, better, an icon link on the Documentation Center home page?
Jul
21
comment Easiest Way to Use ShowGroupOpener in Mathematica
@Ben Allgeier: Right! You apply the GroupOpener to the Input/Output group after you evaluate the Input cell. If you double-click the Output cell it hides the Input cell but leaves the GroupOpener on the Output cell. But then when you open the group, the GroupOpener appears as if on the Input cell -- really on the whole group, which always means the first cell within the group. Thus this seems to achieve what you originally asked: display only the Output but have the GroupOpener displayed as a way to display the Input too.