re-frame | A VanillaJS take on Clojure 's fantastic re-frame library | Graphics library
kandi X-RAY | re-frame Summary
kandi X-RAY | re-frame Summary
A VanillaJS take on Clojure's fantastic re-frame library
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
- Creates the app store .
- Set up the time history .
- Test if object is deep recursive .
- processEvents queue
- Subscribe to a Query
- wrap the http config
- creates a new atom
- Register a subscription .
- Asserts that an interceptor is valid .
- Creates interval .
re-frame Key Features
re-frame Examples and Code Snippets
Community Discussions
Trending Discussions on re-frame
QUESTION
I'm trying to create a prototype SPA which consists of a form with two fields (title and description) and a submit button. On submit, the submission title will be added to a list of items that are being displayed (which I've modeled as a React Native FlatList).
For this, I'm using the template created by PEZ for React Native development: https://github.com/PEZ/rn-rf-shadow. This uses React Native, Expo, Reagent, and re-frame.
The problem here is with the FlatList component. Here is how I have structured it:
ANSWER
Answered 2021-Nov-20 at 06:11You are calling (spaces) as a function but it is actually a function? If it actually is a vector you just need (mapv :title spaces)?
shadow-cljs offers Inspect to quickly verify that you are actually working with the data you think you are working with. For example you can do something like
QUESTION
I'm very new to the cljs. I'm practicing the cljs with re-frame. I faced an issue to access a method of js instance.
...ANSWER
Answered 2021-Jun-13 at 08:38It is due to lacking externs. Add ^js in front of @editor:
QUESTION
Example of code to illustrate my issue here.
...ANSWER
Answered 2021-Jun-09 at 16:59We can unnest the list column before doing the join
QUESTION
As a newbie in Clojure I'm trying my first re-frame app. It is a wizard containing sections. Each of the sections can contain one or more components. Each component could be a text-block, numeric input, ...
But if I change a value of a component in REPL, by dispatching the set-component-value event, the html doesn't get rerendered to show the updated value. However I do see in re-frisk debugger that the db gets updated.
ANSWER
Answered 2021-Mar-04 at 10:24Solved,
1st, I commented out a bit too much while debugging the component-data subscription
2nd, the function parameter of component-data was not right
QUESTION
trim_with_solid is called:
ANSWER
Answered 2020-Dec-12 at 11:49Previously, I was using Qt3DExtras::QCylinderMesh as solid B (VB and FB). But it was NOT watertight. I replaced it with the following code which creates watertight cylinders.
QUESTION
Using lein re-frame template I see that there's a -main function that runs a jetty server for the backend code located in clj/. Using emacs I've been able to cider-jack-in-cljs and get the frontend running in the browser, hot reload works and all but I've tried to add routes to the routes function in handler.clj inside the clj/ and haven't been able to figure out how to get that "backend side" of things to work.
I found this other question sort of related but in that case the user just wanted to know why the clj/ folder was there, not how to run that code. I haven't been able to find any documentation so far, any help is greatly appreciated.
PD: I know that having the backend and frontend in the same project/repo is not recommended (it's mentioned in the other question I linked above) but I just want to get a simple "first app" working and running first and then hopefully get the backend out into another project/repo.
...ANSWER
Answered 2020-Nov-04 at 08:08Assuming you created the project with something like lein new re-frame myapp +handler the code to start the server is on the file src/clj/myapp/server.clj
You can open the file and run cider-jack-in-clj, which will ask if you want to launch lein or shadow-cljs. Since it's a CLJ file, choose lein. Once CIDER starts, you can evaluate the -main function (eg. (-main)) to start the server.
You can open the URL at http://localhost:3000 and Jetty will serve the resources that are already compiled by shadow-cljs, so you'll see the same output as viewing the other port from CLJS directly.
Note that the backend code from the template starts the Jetty server but won't help with reloading the backend. To see how enable hot reloading for the backend, check https://github.com/ring-clojure/ring/wiki/Setup-for-development
QUESTION
MTU (Maximum transmission unit) is the maximum frame size that can be transported. When we talk about MTU, it's generally a cap at the hardware level and is for the lower level layers - DataLink and Physical layer.
Now, considering the OSI layer, it does not matter how efficient are the upper layers or what kind of magic-sauce they are applying, data-link layer will always construct frames of size < 1500 bytes (or whatever is the MTU) and anything in the "internet" will always be transmitted at that frame size.
Does the internet's transmission rate really capped at 1500 bytes. Now-a-days, we see speeds in 10-100 Mbps and even Gbps. I wonder for such speeds, does the frames still get transmitted at 1500 bytes, which would mean lots and lots and lots of fragmentation and re-assembly at the receiver. At this scale, how does the upper layer achieve efficiency ?!
[EDIT]
Based on below comments, I re-frame my question:
If data-layer transmits at 1500 byte frames, I want to know how is upper layer at the receiver able to handle such huge incoming data-frames.
For ex: If internet speed in 100 Mbps, upper layers will have to process 104857600 bytes/second or 104857600/1500 = 69905 frames/second. Network layer also need to re-assemble these frames. How network layer is able to handle at such scale.
...ANSWER
Answered 2020-Oct-31 at 16:00If data-layer transmits at 1500 byte frames, I want to know how is upper layer at the receiver able to handle such huge incoming data-frames.
1500 octets is a reasonable MTU (Maximum Transmission Unit), which is the size of the data-link protocol payload. Remember that not all frames are that size, it is just the maximum size of the frame payload. There are many, many things with much smaller payloads. For example, VoIP has very small payloads, often smaller than the overhead of the various protocols.
Frames and packets get lost or dropped all the time, often on purpose (see RED, Random Early Detection). The larger the data unit, the more data that is lost when a frame or packet is lost, and with reliable protocols, such as TCP, the more data must be resent.
Also, having a reasonable limit on frame or packet size keeps one host from monopolizing the network. Hosts must take turns.
For ex: If internet speed in 100 Mbps, upper layers will have to process 104857600 bytes/second or 104857600/1500 = 69905 frames/second. Network layer also need to re-assemble these frames. How network layer is able to handle at such scale.
Your statement has several problems.
First, 100 Mbps is 12,500,000 bytes per second. To calculate the number of frames per second, you must take into account the data-link overhead. For ethernet, you have 7 octet Preabmle, a 1 octet SoF, a 14 octet frame header, the payload (46 to 1500 octets), a four octet CRC, then a 12 octet Inter-Packet Gap. The ethernet overhead is 38 octets, not counting the payload. To now how many frames per second, you would need to know the payload size of each frame, but you seem to wrongly assume every frame payload is the maximum 1500 octets, and that is not true. You get just over 8,000 frames per second for the maximum frame size.
Next, the network layer does not reassemble frame payloads. The payload of the frame is one network-layer packet. The payload of the network packet is the transport-layer data unit (TCP segment, UDP datagram, etc.). The payload of the transport protocol is application data (remember that the OSI model is just a model, and OSes do not implement separate session and presentation layers; only the application layer). The payload of the transport protocol is presented to the application process, and it may be application data or an application-layer protocol, e.g. HTTP.
The bandwidth, 100 Mbps in your example, is how fast a host can serialize the bits onto the wire. That is a function of the NIC hardware and the physical/data-link protocol it uses.
which would mean lots and lots and lots of fragmentation and re-assembly at the receiver.
Packet fragmentation is basically obsolete. It is still part of IPv4, but fragmentation in the path has been eliminated in IPv6, and smart businesses, do not allow IPv4 packet fragments due to fragmentation attacks. IPv4 packets may be fragmented if the DF bit is not set in the packet header, and the MTU in the path shrinks smaller than the original MTU. For example, a tunnel will have a smaller MTU because of the tunnel overhead. If the DF bit is set, then a packet too large for the MTU on the next link, the packet is dropped. Packet fragmentation is very resource intensive on a router, and there is a set of steps that must be performed to fragment a packet.
You may be confusing IPv4 packet fragmentation and reassembly with TCP segmentation, which is something completely different.
QUESTION
I don't understand the tag ":<>" in the following code clojure re-frame todomvc
...ANSWER
Answered 2020-Oct-03 at 08:58That is creating a React Fragment:
QUESTION
After a lot of research and experimentation I've learned a few things which have led me to re-frame the question. Rather than trying to find an "exponential regression", I'm really trying to optimize a non-linear error function with bounded input and potentially unbounded output.
So long as a function is linear, there exists a way to directly compute the optimal parameters to minimize the squared error terms (by taking the derivative of the function, locating the point where the derivative equals zero, then using this local minima as your solution). Many times when people say "exponential regression" they're referring to an equation of the form a * e^(b*x). Ths reason, described below, is that by taking the natural log of both sides this maps perfectly onto a linear equation and so can be directly computed in a single step using the same method.
However in my case the equation a * b^x does not map onto a linear equation, and so there is no direct solution. Instead a solution must be determined iteratively.
There are a few non-linear curve fitting algorithms out there. Notably Levenberg-Marquardt. I found a handful of implementations of this algorithm:
- C++: https://www.gnu.org/software/gsl/doc/html/nls.html
- Python: https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html
- JavaScript: https://github.com/mljs/levenberg-marquardt
Unfortunately I tried all three of these implementations and the curve fitting was just atrocious. I have some sample data with 11,000 points for which I know the optimal parameters are a = 0.08 and b = 1.19, however these algorithms often returned bizarre results like a = 117, b = 0.000001 or a = 0, b = 3243224
Next I tried verifying my understanding of the problem by using Excel. An error function can be written defined as sum((y - y')^2) where y' is the estimated value given your parameters and an input x. The problem then falls to minimizing this error function. I opened up my data (CSV), added a column for the "computed" values, added another column for the squared error terms, then finally used Solver to optimize the sum of the error terms. This worked beautifully! I got back a = 0.0796, b = 1.1897. Plotting two lines on the same graph (original data and estimated data) showed a really good fit.
I tried doing the same using OpenOffice at first, however the solver built into OpenOffice was just as bad as the Levenberg-Marquardt experiments I did, and repeatedly gave worthless solutions. Even when I set initial values it would "optimize" the problem and come up with something far worse than it started.
Having proven my concept in Excel I then tried using optimization-js. I tried both their genetic optimization and powell optimization (because I don't have a gradient function) and in both cases it produced awful results.
I did find a question regarding how Excel's Solver works which linked to an ugly PDF. I haven't taken the time to read the PDF yet, but it may provide hints for solving the problem manually. I also found a Python example that reportedly implements Generalized Gradient Descent (the same algorithm as Excel), so if I can make sense of it and rewrite it to accept a generic function as input then I may be able to use that.
New Question (given all that):How, preferably in JavaScript (though other languages are acceptable so long as they can be run on AWS Lambda), can I optimize the parameters to the following function to minimize its output?
...ANSWER
Answered 2020-Oct-04 at 05:29- My equation is differentiable, I just wasn't sure how to differentiate it. The error function is a sum so the partial derivatives are just the derivatives of the inside of the sum, which is computed using chain rule. This means any nonlinear optimizer algorithm that requires a gradient was available to me
- Many nonlinear optimizers have trouble when very small changes in inputs lead to massive changes in outputs, which can be the case with exponential functions. Tuning the damping parameters or convergence parameters can help with this
I was able to get a version of gradient descent to compute the same answer as Excel after some work, but it took 15 seconds to run (vs Excel ran Solver in ~2 seconds) -- clearly my implementation was bad
More ImportantlySee: https://math.stackexchange.com/a/3850781/209313
There is no meaningful difference between e^(bx) and b^x. Because b^x == e^(log(b)*x). So we can use a linear regression model and then compute b by taking e to the power of whatever the model spits out.
Using regression-js:
QUESTION
I have a problem using the Material UI's Autocomplete with Reagent (ClojureScript). The element renders fine, but when I try to click on it, I get the following exceptions:
ANSWER
Answered 2020-Sep-21 at 08:22Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install re-frame
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page
