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I am reading Agner Fog's optimization manuals, and I came across this example: double data[LEN]; void compute() { const double A = 1.1, B = 2.2, C = 3.3; int i; for(i=0; i<LEN; i++) { data[i] = A*i*i + B*i + C; } } Agner indicates that there's a way to optimize this code - by realizing that the loop can avoid using costly multiplications, and instead use the "deltas" that are applied per iteration

Does SQLite3 safely handle concurrent access by multiple processes reading/writing from the same DB? Are there any platform exceptions to that?

I've read an article about JavaScript parseInt, which had this question: parseInt(0.5); // => 0 parseInt(0.05); // => 0 parseInt(0.005); // => 0 parseInt(0.0005); // => 0 parseInt(0.00005); // => 0 parseInt(0.000005); // => 0 parseInt(0.0000005); // => 5 Why is this happening?

I am currently setting up a boilerplate with React, Typescript, styled components, webpack etc. and I am getting an error when trying to run eslint: Error: Must use import to load ES Module Here is a more verbose version of the error: /Users/ben/Desktop/development projects/react-boilerplate-styled-context/src/api/api.ts 0:0 error Parsing error: Must use import to load ES Module: /Users/ben/Deskto

I made a bubble sort implementation in C, and was testing its performance when I noticed that the -O3 flag made it run even slower than no flags at all! Meanwhile -O2 was making it run a lot faster as expected. Without optimisations: time ./sort 30000 ./sort 30000 1.82s user 0.00s system 99% cpu 1.816 total -O2: time ./sort 30000 ./sort 30000 1.00s user 0.00s system 99% cpu 1.005 total -O3: time .

I'm taking a photo with the newest camera plugin version and I'm using code from flutter example. This is how I pick a camera: final cameras = await availableCameras(); final firstCamera = cameras.first; This is inside init: _cameraController = CameraController( widget.camera, ResolutionPreset.medium, enableAudio: false, ); This is the rest of the relevant code: Future _takePhoto(BuildContext cont

Is there a way to make it so that jest always mocks my modules so I don't need to include it in all my jest tests? Currently I have a config file // src/__mocks__/config.js export default { dbConfig: 'TestDBConfiguration' }; // src/config.js export default { dbConfig: ... // Some other stuff }; To run my unit tests I have to use the mocked config.js. Currently in all my unit tests I have to includ

In order to determine the current locale I found different approaches: Being in the browser, most people suggest looking at the HTTP headers (Accept-Language) Some people suggest consulting navigator.language Being in the backend (Node.js) and apart of HTTP, it is suggested to consult the (system dependent) process.env On the other side, the ECMAScript Internationalization API defines the locales

So, how do I know the scroll direction when the event it's triggered? In the returned object the closest possibility I see is interacting with the boundingClientRect kind of saving the last scroll position but I don't know if handling boundingClientRect will end up on performance issues. Is it possible to use the intersection event to figure out the scroll direction (up / down)? I have added this

I use the new command line tools for Android because the old sdk-tools repository of Android isn't available anymore. So I changed my gitlab-ci to load the commandlintools. But when I try to run it I get the following error: Warning: Could not create settings java.lang.IllegalArgumentException at com.android.sdklib.tool.sdkmanager.SdkManagerCliSettings.<init>(SdkManagerCliSettings.java:428) at com

as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback. I don't want to update it if it exists, as I've read findAndModify does. I have seen many other questions on Stackoverflow regarding this but again, don't wish to update anything. I am unsure if by creating (of

Is it a fair assumption that in v8 implementation retrieval / lookup is O(1)? (I know that the standard doesn't guarantee that)

I have two "unlocked" devices, an iPad mini 3, and a Galaxy Edge 6, both endowed with a terminal and a minimalistic set of unix commands. I thought both devices have arm64 processors but when I ran uname -a on both devices I got the following : for the iPad mini 3 : xxxxs-iPad:/var/mobile root# uname -a Darwin xxxx-iPad 14.0.0 Darwin Kernel Version 14.0.0: Wed Jun 24 00:50:15 PDT 2015; root:xnu-27

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I'm currently trying to poll gpio value with only shell script. I basically developped the script with a test file before using /sys/class/gpio/gpioxx/value This is the solution I found : #!/bin/bash SCRIPT_DIR=$(dirname $(readlink -f $0)) FILE_NAME=$SCRIPT_DIR"/fileTest" while true do inotifywait -qq -e modify $FILE_NAME read val < $FILE_NAME echo $val ### do something here ### done This is worki

Just to clarify, this is a question about backing up a discrete Realm file itself to iCloud Drive, so that it would be visible in the iCloud Drive app. Not synchronizing the contents of the file to a CloudKit store. If you leave the Realm file in the Documents directory, then if the user performs an iCloud or iTunes backup, the file will be backed up. All this means though is that if the user deci

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is there a way to easily recreate the modal presentation style of ios 13' new share sheet? (At first, it's only presented halfway and you can swipe up to make it a "full" modal sheet) I can do it using a completely custom presentation and stuff but is there a "native" api for this behavior so that you don't have to use custom code? Thanks!

All of the following examples use var str = "Hello, playground" Swift 4 Strings got a pretty big overhaul in Swift 4. When you get some substring from a String now, you get a Substring type back rather than a String. Why is this? Strings are value types in Swift. That means if you use one String to make a new one, then it has to be copied over. This is good for stability (no one else is going to c

Three possible solutions that rewire aliased imports to relative paths: 1. babel-plugin-module-resolver Use babel-plugin-module-resolver, while leaving out other babel plugins/presets. .babelrc: "plugins": [ [ "module-resolver", { "alias": { "^@/(.+)": "./src/\\1" } } ] ] Build step: babel src --out-dir dist (output in dist, won't modify in-place) Processed example file: // input // output import

I have the following Dockerfile that uses the latest Ubuntu image pulled from dockerhub: FROM ubuntu:latest RUN apt-get update && apt-get install -y g++ llvm lcov when I launch the docker build command, the following errors occur: Err:2 http://archive.ubuntu.com/ubuntu bionic InRelease At least one invalid signature was encountered. Err:1 http://security.ubuntu.com/ubuntu bionic-security InRelease

I'm logging just fine using dependency injection on my controllers, now I need to log something from a static class. How can I log from a static class? I can't use dependency injection because it's static and I can't just pass in an existing logger object to the static class because it would have the wrong name of class in the log file. In other words how can I get a logger from the loggerfactory

Several times throughout the day, I may be running a test where I need to look through a log file on a remote server. I've gotten used to using my terminal to sftp into the remote server and pull the desired log file down to /tmp on my local machine. I was looking through the options today using man sftp in an attempt to figure out a way to run the following commands basically in a single line so

I would like to get a list of open files in a process on os x (10.9.1). In Linux I was able to get this from /proc/PID/fd. However I'm not sure how to get the same on OS X. I found that the procfs is not present on the OS X (by default. possible implementations present, but I do not want to go that way). So how do I get (natively) the list of open files in a process on OS X. One way is lsof. is th

Background: I'm doing some user interface tests that need to detect if people are paying attention or not. But, this question is not about the page visibility API. Specifically, I would like to know how my Javascript code will be affected if the current tab is not active, or the browser window is not active, in different browsers. I've dug up the following so far: ios 5 pauses javascript when tab

The following steps work fine on macOS Sierra 10.12.4. Note that after brew installs Docker, the docker command (symbolic link) is not available at /usr/local/bin. Running the Docker app for the first time creates this symbolic link. See the detailed steps below. Install Docker. brew install --cask docker Launch Docker. Press ⌘ + Space to bring up Spotlight Search and enter Docker to launch Docker

I am trying to get a large (and working on Xcode 11!) project building in Xcode 12 (beta 5) to prepare for iOS 14. The codebase was previously in Objective-C, but now it contains both Objective-C and Swift, and uses pods that are Objective-C and/or Swift as well. I have pulled the new beta of CocoaPods with Xcode 12 support (currently 1.10.0.beta 2). Pod install is successful. When I do a build, I

I am trying to switch an app I am building over to use Redux Toolkit, and have noticed this error coming up as soon as I switched over to configureStore from createStore: A non-serializable value was detected in the state, in the path: `varietals.red.0`. Value:, Varietal { "color": "red", "id": "2ada6486-b0b5-520e-b6ac-b91da6f1b901", "isCommon": true, "isSelected": false, "varietal": "bordeaux ble