16,783 reputation
41959
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location Ann Arbor, MI
age 76
visits member for 1 year, 9 months
seen 12 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 the classical Greek synthetic form and in the more modern analytical form.


Jul
24
reviewed Reviewed Poincare section for double pendulum
Jul
24
revised Poincare section for double pendulum
deleted 24 characters in body
Jul
24
reviewed Reviewed Replace all instances of Integrate by NIntegrate and add a Method option
Jul
24
revised Replace all instances of Integrate by NIntegrate and add a Method option
Improved formatting
Jul
24
comment Can't get Append to append a record (association) to a dataset
BTW, how did you learn about the existence of TypeSystem package? I can find nothing about it, not in the Documentation Center and not by search Google.
Jul
24
comment Can't get Append to append a record (association) to a dataset
Your discussion of the undocumented 2nd does indicate an intent to enforce type consistency. But the implementation seem inconsistent, since Append enforces type consistency and Insert ignores it.
Jul
24
revised Can't get Append to append a record (association) to a dataset
update about additional question raised by responses
Jul
24
comment Can't get Append to append a record (association) to a dataset
I already knew that "y" would work, but your find concerning y working if the other values of field "b" were symbols is new to me. +1
Jul
24
asked Can't get Append to append a record (association) to a dataset
Jul
23
reviewed Close Expressions to functions, and evaluation
Jul
23
reviewed Close What is wrong with ContourPlot
Jul
23
comment How to generate nonperiodic tilings?
Looking at the image and seeing there is a sub-tiling that forms a rectangle, it seems clear that a periodic tiling is possible with kite and rectangle tiles. In fact, I can see at least three different periodic tilings.
Jul
23
reviewed Close Plot a perfect looking circle using two functions, always look like an ellipse
Jul
23
reviewed No Action Needed Problems with NMinimize
Jul
23
comment How to generate nonperiodic tilings?
This looks to me to be a pure Tom Sawyer request. The OP seems to be saying "This problem is too hard for me, so will someone do it for me?". I say: close it as too broad.
Jul
23
revised How to generate nonperiodic tilings?
deleted 8 characters in body; edited tags
Jul
23
comment Plot a perfect looking circle using two functions, always look like an ellipse
I can't find a question which I think this one duplicates, but this question is addressed in the docs under Plot > Examples > Options > AspectRatio. So suggest closing as "easily found in the documentation".
Jul
23
reviewed Close Making a Logplot with errorbars
Jul
23
reviewed Leave Closed How to solve an integral equation by iteration method?
Jul
23
reviewed Close Take the function f(x)=2x-x^2 and the open interval P=(0,2) why is f(P)=(0,1]? why is that 1 closed?