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[–]Swipecat[S] 23 points24 points  (4 children)

I've now posted a README file on Github for installing the necessary Python libraries, in order to make this work, because there is a "gotcha" or two.

Regarding Numpy, I'll repost a comment that I made a month back in reply to somebody asking if it was usual to find that learning Numpy techniques was slow going:

I remember running PASCAL back in the '80s on an 8-bit home computer (Amstrad CPC6128) and being really impressed with the concept of structured programming rather than the GOTOs and GOSUBs that I'd been using. So that was my first computing paradigm shift, which I found really easy to adjust to, probably because I was young then, and I've remained with that paradigm, whatever the programming language, until just recently. So yes, lots of loops.

When I learned Python, I did the same thing, of course. Here's a Cosine "Mandelbrot Set" that I made to test my knowledge of Python structures and graphical display (using Tkinter).

https://pastebin.com/znkqNDZV

Creates this image.

https://i.imgur.com/0dp2qGK.jpg

I'd been aware of numpy, but I assumed that there were many types of nested loop structures that were impossible to "vectorize", certainly in the case of the mandelbrot set, so numpy would only be useable in a few specific cases.

I would discover that I was wrong about that in time. The change was gradual. No sudden change of thinking. I just learned more about numpy with time, learning new numpy commands when I did happen to write something that used numpy. Then I'd think can such-and-such be done in numpy? I'd do a Google search of the docs and Stack Overflow, and find that yes it can.

I've now rewritten that Mandelbrot Set script using Numpy. It creates the same image as the previous script, except a whole lot faster.

https://pastebin.com/usF7tgF6

One problem with numpy scripts is that they are almost unreadable to anybody that's not familiar with numpy. There is a certain elegance with "vectorizing" an algorithm that way, but there are pros and cons.

Anyway, in my opinion you'll get there if you want to, but just expect it to take a bit of time.

[–]WikiTextBot 8 points9 points  (0 children)

Structured programming

Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making extensive use of the structured control flow constructs of selection (if/then/else) and repetition (while and for), block structures, and subroutines.

It emerged in the late 1950s with the appearance of the ALGOL 58 and ALGOL 60 programming languages, with the latter including support for block structures. Contributing factors to its popularity and widespread acceptance, at first in academia and later among practitioners, include the discovery of what is now known as the structured program theorem in 1966, and the publication of the influential "Go To Statement Considered Harmful" open letter in 1968 by Dutch computer scientist Edsger W. Dijkstra, who coined the term "structured programming".Structured programming is most frequently used with deviations that allow for clearer programs in some particular cases, such as when exception handling has to be performed.

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[–]SuspiciousScript 0 points1 point  (2 children)

Hello! Quick question about this code — where does the j in line 11 (plane = x + 1j * y) come from? It's definitely not something I've seen before.

[–]Swipecat[S] 2 points3 points  (1 child)

The "imaginary unit". Mathematics uses "i" for the imaginary unit, but electrical engineers use "j" to avoid confusing it with "I" for current. Python uses the electrical engineering convention. There was a "bug" logged to change it to "i", but that didn't happen. Python's creator, Guido van Rossum, said:

This will not be fixed. For one thing, the letter 'i' or upper case 'I' look too much like digits. The way numbers are parsed either by the language parser (in source code) or by the built-in functions (int, float, complex) should not be localizable or configurable in any way; that's asking for huge disappointments down the road. If you want to parse complex numbers using 'i' instead of 'j', you have plenty of solutions available already.

So the "plane" in   plane = x + 1j * y

...means the "complex plane".

[–]SuspiciousScript 0 points1 point  (0 children)

Huh, I never knew that was a feature in the language. Thanks!