By Adrien Hamelin | Jan 5, 2017 02:52 PM | Tags: intermediate efficiency
It seems a simple problem, yet…
Applying a permutation to a vector, part 3
by Raymond Chen
From the article:
We spent the last two days looking at the apply_permutation function and arguing pros and cons of various implementation choices. Today's we're going to look at generalization...
By Adrien Hamelin | Jan 5, 2017 02:48 PM | Tags: intermediate efficiency
It seems a simple problem, yet…
Applying a permutation to a vector, part 2
by Raymond Chen
From the article:
We left off our study of the apply_permutation function by wondering which version is bettern: the moving version of the swapping version. I'm not certain I have the answer, but here's my analysis...
By Adrien Hamelin | Jan 3, 2017 02:01 PM | Tags: intermediate efficiency
It seems a simple problem, yet...
Applying a permutation to a vector, part 1
by Raymond Chen
From the article:
Suppose you have a vector indices of N integers that is a permutation of the numbers 0 through N − 1. Suppose you also have a vector v of N objects. The mission is to apply the permutation to the vector. If we let v2 represent the contents of the vector at the end of the operation, the requirement is that v2[i] = v[indices[i]] for all i...
By Adrien Hamelin | Jan 3, 2017 01:48 PM | Tags: efficiency community
Episode 43 of C++ Weekly.
Stack Elision?
by Jason Turner
About the show:
In this episode Jason explores Clang's and GCC's ability to elide stack operations during optimization.
By Adrien Hamelin | Jan 3, 2017 01:40 PM | Tags: community
A very interesting plugin for our blogs:
A new way of blogging about C++
by Yehonathan Sharvit
From the article:
This blog post is about to show a new way of blogging about C++.
Look at a typical blog post about C++: The post usually presents a couple of code snippets. As I see it, there are two pains with code snippets:
- they contain the input and the output but not the actual evaluation of the input
- it’s impossible for the reader to modify the output...
By Marco Arena | Jan 3, 2017 06:40 AM | Tags: intermediate c++17
string_view has recently joined the C++ standard and it can dramatically help your daily job. In this article, after introducing how it works, I show and discuss a few common pitfalls I have met in the last years:
string_view odi et amo
by Marco Arena
From the article:
string_view-like wrappers have been successfully used in C++ codebases for years, made possible by libraries like boost::string_ref. I think all of you know that string_view has joined the C++ standard library since C++17...
By Adrien Hamelin | Dec 30, 2016 03:16 PM | Tags: experimental community
An interesting point of view and implementation of a variant in one article!
My take on variant
by Jonathan Müller
From the article:
C++17 is going to add std::variant. To quote the linked documentation, it is a “type-safe union”. A union is like a struct, but can only store one member at a time. This has many applications, but sadly it doesn’t mix well with non-trivial types, you have to call the destructor yourself etc. Furthermore, nothing prevents you from accessing a union member that isn’t active.
std::variant fixes that. It correctly calls the destructor when switching the active member, it prevents invalid access, etc. However, I’m not quite happy with it and I needed an implementation now. So I’ve decided to implement my own variant as part of my type_safe library.
It was a fun challenge and since my previous attempt was two years ago, I could improve it a lot. Let’s go through some of my design decisions.
By Adrien Hamelin | Dec 30, 2016 02:47 PM | Tags: performance community
Who did not measure wrongly?
Heap fragmentation or how my micro-benchmark went wrong
by David Gross
From the article:
Micro-benchmarking code always looks simple: a few variables, a small for loop and two std::chrono calls. I think this simplicity is an illusion. Micro-benchmarking is either complicated or inaccurate...
By Adrien Hamelin | Dec 30, 2016 02:40 PM | Tags: c++11 advanced
Do you know attributes?
Modern C++ Features: Attributes
by Arne Mertz
From the article:
With the increasing standardization of attributes, we get the opportunity to make our code clearer not only to other humans but also to the compiler and other tools...
By Adrien Hamelin | Dec 29, 2016 01:56 PM | Tags: intermediate experimental
Let's use those fold operators!
Folding Functions
by Sumant Tambe
From the article:
In the last post we looked at basic usage of C++17 Fold Expressions. I found that many posts on this topic discuss simple types and ignore how folds may be applicable to more complex types as well. In this post I'm going to describe folding over functions...