karjudev

from typing import Dict, List

def pagerank(G: Dict[int, List[int]], v: Dict[int, float] = None,
            alpha: float = 0.85, max_iter: int = 1000,
            tol: float = 10e-12) -> Dict[int, float]:
    # Number of nodes in the graph
    n = len(G)
    # Removes self loops from the graph
    for i in G:
        if i in G[i]:

onlurking

Programming as Theory Building

Peter Naur

Peter Naur's classic 1985 essay "Programming as Theory Building" argues that a program is not its source code. A program is a shared mental construct (he uses the word theory) that lives in the minds of the people who work on it. If you lose the people, you lose the program. The code is merely a written representation of the program, and it's lossy, so you can't reconstruct

amaembo

import java.util.*;

@SuppressWarnings("ALL")
class Test {
  static class ReifiedList<T> extends AbstractList<T> {
    private final List<T> delegate = new ArrayList<>();
    private final Class<?> type;

    @SafeVarargs
    ReifiedList(@Deprecated T... unused) {

tfausak

Invertible syntax descriptions

An "invertible syntax description" is something that can be used to both parse and generate a syntax. For example, instead of defining separate toJson and fromJson functions for a given data type, an invertible syntax description could be used to provide both. There are many Haskell libraries that provide this functionality or something close to it. As far as I can tell most of them are at least inspired by Invertible syntax descriptions by Tillmann Rendel and Klaus Ostermann.

Personally I am interested in using these for HTTP routing. I frequently want to be able to define a route such as /episodes/:id.json, dispatch based on that route, and generate links to that route. Doing so manually is tedious and error prone.

tanmatra

/*
 * https://overreacted.io/algebraic-effects-for-the-rest-of-us/
 */

private val effectsStack = ThreadLocal<EffectsFrame>()

fun <T> perform(effectKey: Any): T {
    var frame = effectsStack.get()
    while (frame != null) {
        @Suppress("UNCHECKED_CAST")

elizarov

/*
 * Implementation of backward-mode automatic differentiation.
 */

/**
 * Differentiable variable with value and derivative of differentiation ([grad]) result
 * with respect to this variable.
 */
data class D(var x: Double, var d: Double = 0.0) {
    constructor(x: Int): this(x.toDouble())

elizarov

import kotlin.coroutines.*
import kotlin.coroutines.intrinsics.*

/**
 * Implementation for Delimited Continuations `shift`/`reset` primitives via Kotlin Coroutines.
 * See [https://en.wikipedia.org/wiki/Delimited_continuation].
 *
 * The following LISP code:
 *
 * ```

rxwei

See the official Differentiable Programming Manifesto instead.

bastman

infix fun <T,O>List<T>.cartesianProduct(others:List<O>):List<Pair<T,O>> =
        flatMap{ t:T->
            others.map { o-> Pair(t,o) }
        }

inline fun <T, O, R> List<T>.mapCartesianProduct(others: List<O>, transform: (Pair<T, O>) -> R): List<R> =
        flatMap { t: T ->
            others.map { o -> transform(Pair(t, o)) }
        }

thomasnield

    os.system("kotlinc src/main/kotlin/Launcher.kt -include-runtime -d launcher.jar")

    process = Popen(['java', '-jar', 'launcher.jar', tmp_file_name], stdout=PIPE)
    (stdout, stderr) = process.communicate()