[HN Gopher] Visualizing Complex Functions
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       Visualizing Complex Functions
        
       Author : hyperific
       Score  : 59 points
       Date   : 2024-08-10 07:05 UTC (3 days ago)
        
 (HTM) web link (vankessel.io)
 (TXT) w3m dump (vankessel.io)
        
       | bmitc wrote:
       | A good book is _Visual Complex Functions: An Introduction with
       | Phase Portraits_ : https://www.amazon.com/Visual-Complex-
       | Functions-Introduction...
        
       | azeemba wrote:
       | The animation looks awesome! Looks like the author used
       | matplotlib (as they mention in a comment on the website):
       | https://github.com/vankessel/sandbox/blob/master/graph/inter...
       | 
       | In the past, I have used manim to make mathematical animations:
       | https://www.manim.community/ Manim is more flexible but that
       | comes with some overhead of complexity and learning. Example of
       | some animations using manim:
       | 
       | - List of videos using manim:
       | https://www.manim.community/awesome/
       | 
       | - A blog post I made: https://azeemba.com/posts/degenerate-
       | matter.html
        
         | unconed wrote:
         | I couldn't disagree more to be honest, about this post.
         | Animations are good when they provide object permanence, and
         | let you track what's changing and how.
         | 
         | This post linearly interpolates complex functions blindly,
         | which doesn't tell you anything useful, unless the thing being
         | interpolated is an affine or projective transform where that
         | makes sense.
         | 
         | e.g. For complex powers, the most natural animation is to
         | animate the exponent, which will show a continuous folding or
         | unfolding. Here the squaring just looks like the extra 360deg
         | appears out of nowhere.
         | 
         | For mobius-like transforms, interpolating the inverse might be
         | better.
         | 
         | One particularly good example is e.g. visualizing equally
         | spaced points on a circle, and their various combinations as
         | roots and poles of complex functions.
         | 
         | The goal of math animation should be to highlight and travel
         | the natural geodesics of the concept space, with natural starts
         | and stops too.
         | 
         | The rest is cargo culting.
        
           | seanhunter wrote:
           | Not sure what you mean by this.
           | 
           | > The goal of math animation should be to highlight and
           | travel the natural geodesics of the concept space, with
           | natural starts and stops too.
           | 
           | > The rest is cargo culting.
           | 
           | A geodesic as I understand it is the curve representing the
           | shortest path between two points in some manifold.
           | 
           | So take one thing that I have found math animations useful
           | for: showing the path of travel of some parametric system. Is
           | that a geodesic? Not necessarily in the cartesian space of
           | the system. I don't know what it would mean for it to be a
           | natural geodesic of the concept space.
           | 
           | For me the goal of math animation is the same as the goal of
           | any math visualisation: to improve understanding and
           | intuition. When I animate something (Which I only ever do for
           | myself) that is why I do it. Am I cargo culting in your
           | estimation?
           | 
           | Let's take another example: Say I do an animation of some
           | sort of force problem in mechanics. I can show the paths of
           | some particles in the simulation and the magnitude and
           | direction of the various vectors vs time. Is that cargo
           | culting? It's definitely not any kind of geodesic. Does it
           | help my understanding? Quite possibly.
           | 
           | In that sense in the blog post you are addressing, in my
           | opinion the position vs momentum distribution animation is
           | really great because it really helps my intuition of how
           | those probability distributions are related and how one would
           | change as the other changes.
        
           | ttoinou wrote:
           | I animated the power in this video after 18sec :
           | https://www.shadertoy.com/view/Ms2Bz3
           | 
           | Please note that complex powers involve the complex
           | logarithm, which is multivalued, it should be a surface in 3D
           | to really see the whole function. The animation I made is
           | only taking one value of the power
        
       | fauria wrote:
       | One of the best explanations on imaginary numbers I've seen is
       | Kalid Azad's from Better Explained:
       | https://betterexplained.com/articles/a-visual-intuitive-guid...
        
       | liminal wrote:
       | This is very cool, but would greatly benefit from a perceptually
       | linear color space. I think the author is using HSL -- HCL would
       | be a better choice.
        
         | hyperific wrote:
         | The author's code is available in an archived repo so it should
         | be possible to experiment with different colormaps.
         | 
         | https://github.com/vankessel/sandbox/tree/master
        
       | hyperific wrote:
       | This was also posted previously in 2019.
       | 
       | https://news.ycombinator.com/item?id=19423278
        
       | mkaic wrote:
       | If you want to mess around with these sorts of visualizations
       | yourself, I recommend checking out David Bau's little web app for
       | it: http://davidbau.com/conformal
        
       | ttoinou wrote:
       | Plug of my own work on the topic :
       | 
       | Using images as input to show conformal deformation
       | https://www.youtube.com/watch?v=CMMrEDIFPZY
       | 
       | Better phase portraits with a grid, zeroes, poles
       | https://www.shadertoy.com/view/Ms2Bz3
        
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