Comments (3)
Hey Conor, thanks for the bug report. In this case however, it's not a bug (as such), but maybe something I need to be more clear about :)
The flux::scan
adaptor takes a binary function and an optional initial value -- if the latter is not supplied, it uses a default-constructed object of the sequence's value type, which is 0
in this case.
If you don't want to provide an initial value, there's scan_first()
which uses the first element of the sequence as the initial value and applies the operation to subsequent elements. If you use that, it works as expected:
auto iota_scan(int n, auto f) {
return flux::iota(1, n + 1).scan_first(f).template to<std::vector>();
}
int main() {
fmt::print("{}\n", iota_scan(5, std::plus{})); // ✅ [1, 3, 6, 10, 15]
fmt::print("{}\n", iota_scan(5, std::multiplies{})); // ✅ [1, 2, 6, 24, 120]
fmt::print("{}\n", iota_scan(5, flux::cmp::max)); // ✅ [1, 2, 3, 4, 5]
fmt::print("{}\n", iota_scan(5, flux::cmp::min)); // ✅ [1, 1, 1, 1, 1]
}
https://flux.godbolt.org/z/qqYs3vPvT
The reason for the two functions is that I wanted consistency with fold()
and fold_first()
, the latter of which also doesn't use an initial value. It's mentioned in the documentation but maybe I need to make the difference more clear somehow.
I hope this explains it!
(Also, FYI, you can now select Flux in the "Libraries" tab in Compiler Explorer, so you don't need to do the #include <really_long_path_to_github>
thing any more.)
from flux.
Also, fmt should now be able to print Flux sequences directly without needing to write them to a vector first -- but it's only in the trunk version of fmt for now, so if you want to try it you'll need to #define FMT_HEADER_ONLY
in Compiler Explorer until Victor makes a new release: https://flux.godbolt.org/z/81Tnoc84a
(This should work for all Flux sequences, but it's still new so if you come across any problems please let me know and I'll see if I can fix it.)
from flux.
Ah, that makes sense. I just need scan_first
then! Thanks 🙏
from flux.
Related Issues (20)
- Dropping from an empty sequence asserts HOT 3
- Using Flux to adapt a circular buffer : bug HOT 7
- Add product/permutations/combinations from Python itertools HOT 14
- Suggestion: add a header containing preprocessor macros. HOT 2
- Non const-iterable reversed sequences hard error when used as a range
- Attempted out-of-bounds read in flatten() HOT 1
- take_while should not be random-access HOT 1
- Consistent comparisons
- Internal `std::variant` access optimizations HOT 3
- cartesian_product size() can overflow
- Add zip_map adaptor
- flux::iota prevents auto-vectorization. HOT 4
- Clang Compilation failure HOT 4
- move of `loc` in assert.hpp causes clang-tidy error HOT 2
- cartesian_product::last() sometimes returns wrongly-initialised cursor if one of the source sequences is empty
- Clang crash HOT 2
- strange output, [[2]] instead of [] HOT 2
- Visual studio\code intellisense experience HOT 1
- Blog post shows perf gaps between flux and other approaches HOT 3
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from flux.