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42265
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location Ann Arbor, MI
age 76
visits member for 1 year, 11 months
seen 10 hours ago

I am a retired software developer. I retired at the end of 2003 and since then my computer programming activities have been for recreational purposes. I find Mathematica excellent for that.

I started using Mathematica in 1997 (Ver. 3). I am currently using Ver. 9. Although I have used Mathematica for all kinds of stuff, I use it mostly to pursue my long standing interest in Euclidean geometry, both in its classical Greek synthetic form and in its more modern analytical/transformational form.


Jul
5
revised Using least independent rectangle area to separate every point
deleted 14 characters in body
Jul
5
reviewed Close Add Scroll bar to Panel or Column or Row?
Jul
5
comment Why isn't Compile working for me?
I changed {{x, _Complex}}, the last argument you give to Compile, to {{_, _Complex}} and it seems to work fine. PointFunction[3 + 4*I] now gives 128.719, which is the numeric value of 1108116250625/(4097 Sqrt[4415238971393]).
Jul
5
revised Why isn't Compile working for me?
Improved formatting
Jul
5
revised Why isn't Compile working for me?
added 43 characters in body
Jul
5
comment ToExpression fails with long nested string expressions
I can reproduce this with V.9.0.1 on OS X. It looks like a bug to me. The string of braces is built with no problem. It's ToString that's stumbling. I've found another place where Mathematica has trouble with deeply nested lists. See this question. I would say it's a bug.
Jul
5
comment 256 Shades of Grey
@seismatica. Maybe, but I really don't know.
Jul
5
comment Why are functions called first-class objects in Mathematica?
a[[1]] = 6 makes a copy of the list a is bound to, inserts 6 into slot 1 of the copy, and then rebinds a to the copy. The rebinding is done by creating a new delayed rule {HoldPattern[a] :> {6, h, j}} in the own-values of a. Evaluate OwnValues[a] after evaluating a[[1]] = 6 to see it. This can't be done when Set is given {g, h, j}[[1]] = 6 because there no symbol, no a, with a down-value list to modify.
Jul
5
comment Why are functions called first-class objects in Mathematica?
I don't understand what you are saying. a = {g, h, j}; a[[1]] = 6; a works fine for me. {g, h, j}[[1]] = 6 can never work for the reasons I gave in my answer. What symbol do you think Set will rebind in latter expression?
Jul
5
revised 256 Shades of Grey
Added remark on 8-bit display on web pages
Jul
5
revised 256 Shades of Grey
Edited answer to better address OP's question
Jul
5
comment 256 Shades of Grey
It's certainly possible to generate such images, but you see all the colors distinctly. You will get a nice gradient, though.
Jul
5
revised 256 Shades of Grey
Added example showing a gradient with 256 shades of gray
Jul
5
answered 256 Shades of Grey
Jul
5
comment 256 Shades of Grey
Ten grays taken from the range 30/256 to 40/256 are not distinguishable to most human eyes. What do you really want?
Jul
4
answered Why are functions called first-class objects in Mathematica?
Jul
4
revised Create a color bar plot legend
edited title
Jul
4
comment Liouville theorem demonstration
Be careful not to use E as a symbol for energy in your code. Mathematica reserves this symbol for the base of the natural logarithms.
Jul
4
revised Liouville theorem demonstration
Moderate clean-up
Jul
4
revised Problems with Solve
Improved formatting