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Congruential Luminaire > Congruentia Luminaire Blog
ideas about congruent light
decided to go with the HP B9180
I had originally planned on the Epson Stylus R2400.
 
Apparently this box is comparable and exceeds the Epson in some ways. Also there appears to be a fairly broad user base to help me run into (and hopefully resolve) all of the problems.
 
It is interesting to note that like the $99 HP printer, this $800 printer costs about 33% of the original cost to fill it with ink one time! :-(
 
Below is a list of references. Note that I found the last two below to be the most comforting.
[customer comment from] a Mma engagement doing economic analysis
I recently did a small engagement for this litigation support company in the East Bay. Here is the comment they sent me about my work:
 

Over a very short time period, Roger came in and understood our existing Mathematica code environment, resolved several code issues and got multiple operational reports running to the clients satisfaction. He demonstrated considerable familiarity with Mathematica V5 and V6 as both were in use in our environment. Further he helped us validate the accuracy of the code logic and statistical computations.

Roger's Mathematica resume
I have loaded the one I used recently (here) and as a .pdf (here).
 
Regards..
Errors on the New in Version 6 pages
This page describes the additions to the V6 version.
 
 
GraphPlot[ExampleData[{"Matrix", "HB/Blckhole"}, "Matrix"], VertexRenderingFunction -> None]
 
It should say:
 
GraphPlot[ExampleData[{"Matrix", "HB/blckhole"}, "Matrix"], VertexRenderingFunction -> None]

--------------------------------------
The Automatically Pick Out Features in Matrices page says:
 
MatrixPlot[ExampleData[{"Matrix", "DNVS/Ship001"}, "Matrix"]]
 
It should say:
 
MatrixPlot[ExampleData[{"Matrix", "DNVS/ship_001"}, "Matrix"]]
---------------------------------------
The Built-in Example Data page says:
 
ListContourPlot[
 Reverse[ExampleData[{"TestImage", "Lena"}, "GrayLevels"]],
 ColorFunction -> "Rainbow"]
 
I have not figured out the fix for this yet. The code causes the system to loop.
 
Regards..
The next wave in Numerical Computing?
This is a good YouTube video by a Sun guy who apparently wants Google to adopt what this guy calls: The Mother of all paradigm shifts.
 
The presentation is pretty good, very clear and convincing until you get to the Q&A period about 50 minutes into the video. After the guy has trouble answering some of the audience questions, it sounds more like a sales pitch.
 
The author G.William Walster has been awarded a patent  using this in solving nonlinear systems of equations.
 
Mma has an interval type that I have not experimented with very much. Interval arithmentic is discussed in the Beginners Guide to V4 (included in the V5 Help system) in a chapter on roundoff errors.
 
Regards..
PlotPoints-> arguments & V6
I am learning lots by reading the Trott's Numerics Guidebook. I came across this PlotPoints spec, so I sent a note to the author. My note and his reply are excerpted below.
 
Regards..
----------------------------------------------------
I am going through the Numerics guidebook and I have come across the following construct in one of the solutions (page 606-Clebsch surfaces):
 
PlotPoints -> {{8,4},{8,3},{22,3}}
 
I look at your code using V6 since the Notebook interface is some much more friendly to reading long code passages (otherwise I would not be inspecting this option). I look at my PlotPoints setting quite often since it is so closely related to  the displayed output as well as the performance.
 
Anyway, V6 complains that this is an invalid specification. Of course it runs just fine under V5.
 
But in the PlotPoints help for V5, it does not explain this construct. It only describes a single scalar for sample points in each direction.
 
So, I have 2 questions about this.
- Is this documented somewhere?
- Is there a corresponding construct that is valid in V6?
----------------------------------------------------
The V5 syntax indicated how to deal with the number of plotpoints in 3D contour plots at the various subdivision stages. In V6, after the initial sampling, always one point is added per dimensions.
 
So the approximate equivalent of PlotPoints -> {{8,4},{8,3},{22,3}} would be
 
PlotPoints -> {8, 8, 22}, MaxRecursion -> 1

But this will not make all of the code of this solution work.
In V5, ContourPlot3D returned a Graphics3D object that contained polygons.
 
In V6, a GraphicsComplex is returned. So one must apply  Normal to resolve the GraphicsComplex into polygons. And one has potentially to remove the vertex normals.
a presentation about Mma programming style
This is a presentation I came across that was given at the Wolfram Technology conference this year. It is entitled A New Mathematica Programming Style. It starts with a quote from SICP. That is always a good sign. Then it goes on to postulate an alternative style (=collection of idioms) to use in Mma programming.
 
The weird thing is that I have been thinking about this same subject as I attempt to decipher the code in Trott's Numerics Guidebook. My thinking is not nearly as far along as this person's, but code readability is very important to me. I started realizing that as I study Mma code, use of the double bracket for Part[] and shorthand operators for Map[] or even Sqrt[] make the code much more compact and easier (for me) to read/study. I was even starting to make some examples for a blog posting in a similar way to some better examples in this presentation.
 
Ever since I took M221 from Roman Maeder before the WTC in 2004, I have some experience trying to get my head around somewhat complicated functional programming constructs. I only started on Trotts book this year and I have been surprised how some of the code makes sense that would not have made any sense to me 2 years ago.
 
In particular, Trott uses pure functions directly with the arguments and not only as Map[] arguments (or lhs of /@) and I had not seen much of this before reading his book. I am not sure if that is harder to read than some other format. I sometimes do take the code and re-factor it to have some meaningful function name to make it easier to read and explain to people.
 
The presentation also discusses this issue in relation to operator precedence. Because I have been thinking about this, I recently posted a question about this on MathGroup entitled What is the precedence wrt Mathematica infix operators. I was surprised that a couple of Wolfram people chimed in.
 
Another data point about this is a recent article by Paul Graham called Holding a Program in One's Head. One of his points is that succintness is power (in a programming language). Interestingly, Stephen Wolfram is credited as a reviewer.
 
The author of this presentation is planning a forthcoming book, so I need to keep my eye peeled for more info about this. Also, I have not finished studying the presentation itself, so I need to provide more detailed feedback to the author.
 
Regards..
Excel 2007 computations are whack!
In this presentation, the author invites the reader to verify the following simple computation in Excel 2007: 850 x 77.1 - 100000!?!?!
 
I hope my financial records are not being computed with this!
 
Regards..
A 22-year old running a biotech company based on her own patent
This is a company on the peninsula run by a young woman who dropped out of Stanford. She even got the Dean at her school to be on the board of her company called Theranos.
 
Their product is based on a patent she holds. Basically, it is a device that takes a drop of blood by pricking the skin of the finger (like a diabetes machine). Then a chip in the device does some analysis of the blood and sends the data back to a web site at this company.
 
The computers at the company determine if there are any drug interactions for that person.
 
The podcast of an interview with this woman is here. Very interesting!
 
Regards..
The Delta Chronicles Part Deux
I finally got into podcasting. This is after several people told me to put something out there!
 
I have been hearing about all of the stuff that people are planning to put out on YouTube. After this first experience it does seem more suited to the first video I watched yesterday called 'High School' (see it here). This is better than I thought actually!
 
I have been swimming in Mathematica and that is what this web site is about so I decided to try to create an educational video for Mathematica and post it out on YouTube.
 
I would say that my experience with YouTube is mixed mainly for 2 reasons:
  • the resolution they use is very low (it is only 320x240)
  • the video length restriction is only 10 minutes (I am finding it hard to give a complete lesson in 10 minutes)
But this is only a problem with YouTube, not podcasting. So for now, I ended up putting my longer efforts and higher resolution efforts out on my Amazon S3 space.
 
Amazon S3 is a pay-as-you-go cheap huge disk area in the cloud.
 
Here is the story on my first few videos.
  • The first one is on YouTube. Check it out here. It is called A First Taste of Mathematica and it is a low-res intro session that lasts almost 10 minutes (the YouTube maximum).
  • The next one was rejected by YouTube because of it's length (21 minutes). It is called Another Part of the First Taste and it is accessible from my S3 space here.
  • The third one is definitely the best one and gets closest to the Delta Chronicles type of video since it has higher resolution, includes a musical introduction and some dramatic graphics at the end. It is called Fourier Tricks and you can see it here.
I am OK with all of these videos since they all have a logical flow and shows I am not a novice at this.
 
My current plan is to make a short teaser of each video and post it on YouTube. Then I gotta figure out how to charge people to learn this stuff or run my own webinars
 
Finally, the title of this blog entry is a reference to my now defunct TV show on Channel 29 Access San Francisco. I produced and broadcasted about 12 shows that I will probably reprise and rebroadcast to the blogosphere.
 
Regards..
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A screenshot from the video
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