laszlokorte

16 ms·

151.
by laszlokorte 5y ago
> I mean, true in a technical sense, but don't all the sample functions here have known analytical Fourier transforms? Yes but currently I make not use of it but simply apply the DFT on the samples of the function. Making use of the
152.
by laszlokorte 5y ago
Thanks! I will put the source code on github but actually its just plain html/css/js that has not been preprocessed so the source code can be viewed right in the browser.
153.
by laszlokorte 5y ago
Yes, I mean 'time and spectral domain'. The idea of the gif is to represent the two domains orthogonal to each other graphically. The signal in the time domain is a complex function (time->(magnitude,phase)) so it can be plotte
154.
Show HN: Fourier Transform Visualized via WebGL(static.laszlokorte.de)
175 points by laszlokorte 5y ago|23 comments
155.
by laszlokorte 5y ago
I built this visualization while taking a signal processing course. The goal is to demonstrate the duality between transformations in the time and spectral domain. For example shifting the signal along the time axis results in a linear phas
156.
by laszlokorte 5y ago
They hope one day you will join them... and dont forget to press the like button, subscribe to the channel and hit the bell to get all the notifications
157.
by laszlokorte 5y ago
Wouldn't it have been simple/easy to define a facade in front of sqlite as the standard? Like some basic SQL select/insert/update/create table/drop table syntax and semantics? In a way such that advanced/s
158.
by laszlokorte 5y ago
„Valid“ does not mean syntactically valid but „true in any case“
159.
by laszlokorte 5y ago
On the left side there are some tools for running algorithms on the graph. some are not implemented yet. But for example the "play" icons allows you to run djikstra or topological sort algorithm.
160.
by laszlokorte 5y ago
Wow, this looks really nice and reminds me alot of a tool I built myself 2 years ago. [0] The overlap in ideas is really astounding. I really like the way the nodes can be grouped in bags and how each step of running topo-sort or dijkstra i
161.
by laszlokorte 5y ago
Except if you build a complete query builder as a stored procedure I do not see the problem solved. Simply stated the problem is: Viewing code as data (in a lisp sense) and transforming arbitrary data into a query that can be executed.
162.
by laszlokorte 5y ago
The issue with plain SQL is simply that you can not compose queries at runtime. For example let user decide which columns to select, in which order to fetch the rows, which table to query etc. Or not even let the user decide but decide bas
163.
by laszlokorte 5y ago
I agree with you in that I do not understand why anybody doing something illegal would upload related data to a cloud storage. But if nobody would import CSAM into their icloud library why do all the pictures need to be scanned in the first
164.
by laszlokorte 5y ago
One of the major motivations for concepts is to allow better error messages.
165.
by laszlokorte 5y ago
big O() notation is simply not precise enough (and not meant to be) to be used in such nitpicky discussions. Everything is O(1) for a large anough constant, for example O(live time of the universe). There are other notations like small o(),
166.
by laszlokorte 5y ago
Looks pretty neat but one thing immediatly noticed: When clicking in in the menu bar to open a menu (for example on the apple logo) and then moving the mouse down, but diagonally in a way that the cursor cross the next to the right menu ite
167.
by laszlokorte 5y ago
It says the O2 (ISP) has no IPv6 support but as a O2 DSL customer in Germany I have an IPv6 address for at least a few years.
168.
by laszlokorte 5y ago
Funny in germany we learn the formular for just that: Area_triangle = Base_triangle * Height_triangle / 2 /edit: fixed factor of two
169.
by laszlokorte 5y ago
Like a membership card of some store/club only used for collecting discounts.
170.
by laszlokorte 5y ago
A fun song by Acapella Science featuring the discovery of insulin [0] [0]: https://www.youtube.com/watch?v=He7X5jGt8lY
171.
by laszlokorte 5y ago
Could you give a concrete example for such a check constraint? I imagine each shape-table would need to have it's own check to test the existence of the same id in all other shape tables, which scales qudratically. Or if you inverse th
172.
by laszlokorte 5y ago
As I said in response to a sibling: But can you can not (in a simple way) prevent that both a circle and a triangle point to the same user and you can not enforce a NOT NULL for a user to must have a favourite shape.
173.
by laszlokorte 5y ago
But can you can not (in a simple way) prevent that both a circle and a triangle point to the same user and you can not enforce a NOT NULL for a user to must have a favourite shape.
174.
by laszlokorte 5y ago
Thinking a bit more about it I think this would be a very elegant solution for Tagged-Unions in SQL: - simply allow tagged unions for foreign key constraints: CONSTRAINT my_fk FOREIGN KEY (own_column) REFERENCES EITHER table_a (a_id) OR tab
175.
by laszlokorte 5y ago
But if I have a circle relation and a triangle relation, how do I create a foreign key for the favourite_shape column in my user relation?
176.
by laszlokorte 5y ago
I really like the style of your visualizations! I built something similar while learning for my algorithms course ate university. [0] It not fully polished yet and not algorithms I had planned to implement are done yet. But I learned a lot
177.
by laszlokorte 5y ago
Still does not make sense to me: OrigTableA = {(ruby, 5), (rust,7), (php, 3)} OrigTableB = {(red, 5), (black, 7), (purple, 3)} OrigTableA \cap OrigTableB would be empty, makes no sense OrigTableA \cup OrigTableB would conain all 6 elements,
178.
by laszlokorte 5y ago
Yeah the overlapping circles make absolutely no sense because typically they are used to visualize operations on sets of the same kind resulting in a third set of also the same kind. But when joining two tables the two base sets are of diff
179.
by laszlokorte 5y ago
before you copy my code I own [the only copy] after you steel/copy it I no longer own [the only copy]
180.
by laszlokorte 5y ago
I agree that ideally the code could be organized a lot better, but think about it like this: It is the fully working safari UI in only 1000 lines of code. Additionally the declarative approach of SwiftUI together with the type system makes

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