From 166d08633af20c81a24c70f47c5961851591b6ec Mon Sep 17 00:00:00 2001 From: Daniel Vainsencher Date: Fri, 29 Jan 2021 09:15:47 -0800 Subject: [PATCH] Add licensing information (#12) Also an .gitignore --- .gitignore | 1 + COPYING | 3 + LICENSE_APACHE.md | 201 ++++++++++++++++++++++++++++++++++++++++++++++ LICENSE_MIT.md | 21 +++++ README.md | 111 ++----------------------- 5 files changed, 233 insertions(+), 104 deletions(-) create mode 100644 .gitignore create mode 100644 COPYING create mode 100644 LICENSE_APACHE.md create mode 100644 LICENSE_MIT.md diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..ea8c4bf --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +/target diff --git a/COPYING b/COPYING new file mode 100644 index 0000000..29dc35f --- /dev/null +++ b/COPYING @@ -0,0 +1,3 @@ +This project is dual-licensed under the Apache 2.0 and MIT licenses. + +You may use this code under the terms of either license. diff --git a/LICENSE_APACHE.md b/LICENSE_APACHE.md new file mode 100644 index 0000000..6ca1f3a --- /dev/null +++ b/LICENSE_APACHE.md @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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We also recommend that a + file or class name and description of purpose be included on the + same "printed page" as the copyright notice for easier + identification within third-party archives. + + Copyright 2021 Daniel Vainsencher and Daniel Fox + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. diff --git a/LICENSE_MIT.md b/LICENSE_MIT.md new file mode 100644 index 0000000..a06a22a --- /dev/null +++ b/LICENSE_MIT.md @@ -0,0 +1,21 @@ +MIT License + +Copyright (c) 2021 Daniel Vainsencher and Daniel Fox + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in all +copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE +SOFTWARE. diff --git a/README.md b/README.md index a4d4048..4285318 100644 --- a/README.md +++ b/README.md @@ -1,106 +1,9 @@ -# You have a numerical problem. +Iterative methods and associated utilities in Rust. -## You applied an iterative method naively, now you have 10 problems that recur forever. - -Suppose we have a problem, and initial solution (probably bad) and a -function f such that f(x) is a better solution than x by some numeric -cost measure g. Then applying f repeatedly gives us a sequence of ever -better solutions, hopefully converging to an optimal solution. The -most common initial "I want to see this work!" implementation looks -like: - - x = x0 - for i in 100: - x = f(x) - -But as soon as you've implemented such a method, many additional -considerations come up: -- are 100 iterations enough? -- are x actually ever improving? -- how long is each iteration taking? -- perhaps we want to log every 10th x for later plotting? -- it crashed after 2 days of iterations, perhaps I should have saved - intermediate iterations... - -Following the path of least resistance, we might add `print(g(x))` at -the end, move `print(g(x))` into the loop, use timers and print -differences, etc. In general, we find ourselves adding a few lines of -code, then moving, deleting, re-adding, commenting them out... and on -the next project perhaps copy and pasting them again. - -Some of the time, answering our questions require access to internal -state of f, which therefore gets inlined into the loop, and now all -these external concerns are mixed with the algorithm, possibly adding -bugs to the very algorithm they were supposed to help understand! - -Argh! - -## Can't we just write the algorithm once, write each utility once, and somehow do only the wiring together we need? - -Yes, kind of, but it is language specific. LT;DR: - -* f should not be a black box that transforms solutions x; it should - instead take and returns a struct s with all interesting state of - the algorithm. -* To start the sequence of states, convert a problem p into an initial - state s0 -* Abstract the repeated application of f as a stream of states s, - assuming your language has one. -* Abstract the utilities as stream adaptors. Such a utility takes a - stream and applies to each a transformation (e.g., measure value), a - side effect (log some states) or both. - -I did not invent this approach, and will happily add further -references!; briefly, this hope has a long history of programming -language specific ([a Haskell mailing list circa -2006](https://mail.haskell.org/pipermail/haskell-cafe/2006-August/017394.html)) -answers. A recent and nice entry tackling this problem in Julia is -"[Iterative methods done right (because life is too short to write -for-loops)](http://lostella.github.io/2018/07/25/iterative-methods-done-right.html)" -(referred to as IM below) proposes to write iterative methods as Julia -iterators and various utilities for them as iterator adaptors. I -recommend reading their exposition, which inspired this project! - -# How deep can we follow this path in rust? - -Rust seems promising for many reasons. - -* Rust loves abstracting sequences; iterators are a (the?) first class - citizen in, e.g., for loops. -* In Rust abstraction costs are low, so won't dominate the work even - when iterations are pretty cheap. -* It is a language essentially optimized for writing high efficiency - reusable abstractions, so when iterator is not an exact fit, we can - use a variation. - -## The simplest thing and how it fails - -In simple cases, Rust iterators will do. We even have some nice little -adaptors pre-made, like `enumerate` with annotates our state with its -location in the stream, and `take` which stops after the given -iteration number: - - for (i, state) in convert_problem_to_iterator(problem).enumerate().take(4) { - println!("Iteration {} has state {}", i, state); - } - - -# TODO here -* rework the fib example, can we actually output the state instead of - the next value? -* Understand rustdoc better. Link to the fib code examples? Does it - make sense to make this whole essay literate code using rustdoc? - -And we can go quite far with this direction, as long as state is cheap -to copy. The caveat is because iterators return values, not -references, and so for the iterator to own them and the loop body and -down stream adaptors to have access requires copies. Some might be -optimized away by a [sufficiently smart -compiler](https://wiki.c2.com/?SufficientlySmartCompiler) and Rust is -plenty smart, but the Rusty approach to reliable efficiency is to -minimize copies and make them explicit. - -Some unprocessed links: - -1. https://docs.rs/streaming-iterator/0.1.5/streaming_iterator/ +# Licensing +This project is dual-licensed under the [Apache](LICENSE_APACHE.md) +and [MIT](LICENSE_MIT.md) licenses. You may use this code under the +terms of either license. Contributing to this repo in any form +constitutes agreement to license any such contributions under all +licenses specified in the COPYING file at that time.