- std::bless - 2 Updates
- C++ threshold for "stupid" sorting algorithms (O(n^2)) - 4 Updates
- Wading through template instantiation errors for allocator - 1 Update
- std::copy with std::ostream_iterator<std::array...> - 4 Updates
- Don't be fooled by cpp.sh - 3 Updates
- little contest - 2 Updates
| Mr Flibble <flibbleREMOVETHISBIT@i42.co.uk>: Jan 05 08:53PM Hi, I find the name of std::bless and the subsequent concept of "blessing" things in C++ as offensive to both my beliefs (as I am a militant atheist and anti-theist) and to the concept of keeping religion out of the technical/scientific/engineering arena (similar to the concept of separation of church and state). I am assuming that this is just a place holder name and that the C++ Committee hasn't been overrun with god bothering fucktards. /Flibble -- "Snakes didn't evolve, instead talking snakes with legs changed into snakes." - Rick C. Hodgin "You won't burn in hell. But be nice anyway." – Ricky Gervais "I see Atheists are fighting and killing each other again, over who doesn't believe in any God the most. Oh, no..wait.. that never happens." – Ricky Gervais "Suppose it's all true, and you walk up to the pearly gates, and are confronted by God," Byrne asked on his show The Meaning of Life. "What will Stephen Fry say to him, her, or it?" "I'd say, bone cancer in children? What's that about?" Fry replied. "How dare you? How dare you create a world to which there is such misery that is not our fault. It's not right, it's utterly, utterly evil." "Why should I respect a capricious, mean-minded, stupid God who creates a world that is so full of injustice and pain. That's what I would say." |
| "Öö Tiib" <ootiib@hot.ee>: Jan 05 03:00PM -0800 On Sunday, 5 January 2020 22:53:49 UTC+2, Mr Flibble wrote: > I find the name of std::bless and the subsequent concept of "blessing" things in C++ as offensive to both my > beliefs (as I am a militant atheist and anti-theist) and to the concept of keeping religion out of the > technical/scientific/engineering arena (similar to the concept of separation of church and state). Uhh. Calm down, what is that std::bless even supposed to be? Never heard of it. > I am assuming that this is just a place holder name and that the C++ Committee hasn't been overrun with god bothering fucktards. And also in your proposals you can likely be more constructive. Propose alternatives std::endow, std::favor, std::preserve and avoid mentioning fucktards. ;) |
| Bonita Montero <Bonita.Montero@gmail.com>: Jan 05 03:01PM +0100 >> That's not true. You're a liar. > That's a nasty thing to say. If I thought you were a serious > contributer, I'd be offended. Try the fixed code. The fixed code gives this with gcc on my computer: size: 2 bs: 0.7988 s: 1.2735 size: 3 bs: 0.9466 s: 1.5443 size: 4 bs: 1.2005 s: 1.6128 size: 5 bs: 1.5233 s: 1.9473 size: 6 bs: 2.353 s: 1.9982 --- size: 7 bs: 2.2377 s: 2.365 size: 8 bs: 4.0274 s: 2.727 size: 9 bs: 3.4135 s: 3.2835 size: 10 bs: 4.171 s: 3.269 size: 11 bs: 4.7766 s: 3.7635 size: 12 bs: 5.6038 s: 4.1902 size: 13 bs: 7.9656 s: 4.0113 size: 14 bs: 8.9014 s: 4.5925 size: 15 bs: 9.9181 s: 4.7311 size: 16 bs: 11.1119 s: 4.9711 size: 17 bs: 12.4162 s: 6.0172 size: 18 bs: 14.4748 s: 6.85 size: 19 bs: 15.8686 s: 7.1291 size: 20 bs: 20.8648 s: 7.2139 Above 5 elements quicksort ist faster. |
| Melzzzzz <Melzzzzz@zzzzz.com>: Jan 05 03:16PM > just reporting on the output. > Third, the OP was not just about bubble sort. To get a sound answer > from measurements, the best simple sort, insertion sort, should be used. I use quicksort then insertion sort when partition falls down bellow 15 elements... I think this is common knowledge. -- press any key to continue or any other to quit... U ničemu ja ne uživam kao u svom statusu INVALIDA -- Zli Zec Svi smo svedoci - oko 3 godine intenzivne propagande je dovoljno da jedan narod poludi -- Zli Zec Na divljem zapadu i nije bilo tako puno nasilja, upravo zato jer su svi bili naoruzani. -- Mladen Gogala |
| Soviet_Mario <SovietMario@CCCP.MIR>: Jan 05 09:13PM +0100 On 05/01/20 05:03, Bonita Montero wrote: > be billions of such sorts. And I measured that bubblesort is > even > slower for a few elements; that's not apparent. If I did understand right, Ben was saying that very short sorting could be repeated thousands of times (not meaning sorting thousands of items, but some tens of items in thousand occasions : giving a multiplier of advantage or disadvantage). Anyway : to sum up this thread. I've found the stable_sort in the header algorithm. I did not fully understand its internals (a template of too much parameters obscure to me), so I have decided to recode the 10 lines long example Gnome Sort (optimized version) from Wikipedia. Moreover I have to adapt it to sorting rows / columns of a rectangular matrix, where the key-field is a parameter and whole columns/rows have to be moved, not just the key-field As I did not well understand the standard algorithm version, I gave up with it in this more customized sorting. Tnx to all -- 1) Resistere, resistere, resistere. 2) Se tutti pagano le tasse, le tasse le pagano tutti Soviet_Mario - (aka Gatto_Vizzato) |
| Ben Bacarisse <ben.usenet@bsb.me.uk>: Jan 05 10:26PM >> That's a nasty thing to say. If I thought you were a serious >> contributer, I'd be offended. > Try the fixed code. The fixed code gives this with gcc on my computer: No apology for accusing me of lying I see. The fixed code does not alter what I said: the simple sort is faster for all your test sizes for some data sets -- specifically when the data are already sorted. The factor is now smaller (no longer always greater than 2) but still between 1.5 and 2. -- Ben. |
| Manfred <noname@add.invalid>: Jan 05 10:31PM +0100 On 1/4/2020 11:34 PM, Frederick Gotham wrote: > cout << elem << endl; > } > Now I can get back to testing my new allocator. The following satisfies the rebind requirement, although I do not know how this may play in a more elaborate context: template<typename T, std::size_t capacity> class StaticAllocator { public: typedef T value_type; protected: static T buf[capacity]; public: template<typename U> struct rebind { typedef StaticAllocator<U, capacity> other; }; T *allocate(std::size_t const n) { if (n > capacity) throw std::bad_alloc(); return buf; } void deallocate(T *, std::size_t) { /* Do Nothing */ } }; |
| Ralf Goertz <me@myprovider.invalid>: Jan 05 04:06PM +0100 Am Sat, 4 Jan 2020 21:46:28 -0000 (UTC) > Do you want (2,1) to be less than (1,2) ? if you want to define a > lexicographical order on (i,j), the comparison should be > return i<r.i || (i==r.i && j<r.j); Yeah, I know. I did get it wrong but I only defined the operator in order to be able to use Foo with the set. I was puzzled by the compile errors with array. I thought that the fact that array is templated could be the reason. So I tried the non-templated Foo and the errors were gone. I would never have guessed that the namespace was the problem. |
| Jorgen Grahn <grahn+nntp@snipabacken.se>: Jan 05 06:24PM On Sun, 2020-01-05, Ralf Goertz wrote: >> lexicographical order on (i,j), the comparison should be >> return i<r.i || (i==r.i && j<r.j); > Yeah, I know. I don't know why, but I feel safer defining it like this: bool operator<(const struct Foo &r) const { if (i==r.i) return j < r.j; return i < r.i; } Another option would be std::make_pair, and comparing the pairs. /Jorgen -- // Jorgen Grahn <grahn@ Oo o. . . \X/ snipabacken.se> O o . |
| "Öö Tiib" <ootiib@hot.ee>: Jan 05 10:56AM -0800 On Sunday, 5 January 2020 20:24:38 UTC+2, Jorgen Grahn wrote: > return i < r.i; > } > Another option would be std::make_pair, and comparing the pairs. Funny. I checked that most usual in my code is that pattern: return (l.a != r.a) ? l.a < r.a : (l.b != r.b) ? l.b < r.b : (l.c != r.c) ? l.c < r.c : (l.d != r.d) ? l.d < r.d : l.e < r.e; |
| Jorgen Grahn <grahn+nntp@snipabacken.se>: Jan 05 07:55PM On Sun, 2020-01-05, Öö Tiib wrote: > : (l.c != r.c) ? l.c < r.c > : (l.d != r.d) ? l.d < r.d > : l.e < r.e; "The first pair that's different gets to decide." Makes sense! /Jorgen -- // Jorgen Grahn <grahn@ Oo o. . . \X/ snipabacken.se> O o . |
| Robert Wessel <robertwessel2@yahoo.com>: Jan 05 12:31PM -0600 >Complex has a very niche use case so I can understand that, but VLAs are very >useful if just writing plain C and can't be hard to implement so I don't >understand the decision to make them optional. If so, only because most folks who needed complex numbers moved on to C++ (or rolled their own support in C long ago, and have not replaced that). And don't be so quick to condemn a facility *you* don't happen to use as "niche". In my experience there is *far* more use of complex numbers in C than VLAs. Admittedly only part of that is done with the native C complex type. On the other hand, VLAs present considerable implementation difficulties on some small systems, and present a number of issues with regards to stack growth on all implementations that make people wary of them. Complex support does require some compiler support, but it's just another data type. The actual implementations of the basic functions is pretty trivial, and for small systems can be dumped in a library where it won't get linked if it's not used, so it has no impact on small systems. |
| David Brown <david.brown@hesbynett.no>: Jan 05 08:11PM +0100 On 05/01/2020 19:31, Robert Wessel wrote: > as "niche". In my experience there is *far* more use of complex > numbers in C than VLAs. Admittedly only part of that is done with the > native C complex type. I think it is extremely difficult to guess which features are more or less used, and any attempts will be very biased based on the area of experience of the guesser. With that proviso, I'd be surprised if complex types really were used more than VLAs. > difficulties on some small systems, and present a number of issues > with regards to stack growth on all implementations that make people > wary of them. I disagree. I don't see that VLA implementation would be particularly difficult (in small systems or otherwise). And while it is absolutely correct that you need to be careful about stack use before using them, you don't need more care than you should be taking for any other kind of non-variable local array, or for any other kind of memory allocation. > is pretty trivial, and for small systems can be dumped in a library > where it won't get linked if it's not used, so it has no impact on > small systems. I don't imagine C's complex number support would be that hard to implement either. I really don't understand why these were made optional in C11. Who is going to make a compiler that is C11 compliant but not C99 compliant? Who is going to be capable of making a C11 compiler but find supporting VLA's or complex numbers a major issue? I doubt if their lack will cause a big problem for many people - but sometimes they can be convenient. |
| "Öö Tiib" <ootiib@hot.ee>: Jan 05 11:22AM -0800 On Sunday, 5 January 2020 21:11:28 UTC+2, David Brown wrote: > going to make a compiler that is C11 compliant but not C99 compliant? > Who is going to be capable of making a C11 compiler but find supporting > VLA's or complex numbers a major issue? Yes, _Generic, <threads.h> and <stdatomic.h> sound like work, while VLA's and complex numbers sound like syntax sugar. |
| boltar@nowhere.org: Jan 05 04:29PM On Sat, 4 Jan 2020 20:50:14 +0000 >> same time? >Yes I did: if you don't believe me then you simply have to look at the source >code as it is on github. Now kindly fuck off. No idea where it is on github and I have better things to do that wade through the convoluted mess you'll have written. Plus that tells me nothing about its speed compared to other parsers. |
| Jorgen Grahn <grahn+nntp@snipabacken.se>: Jan 05 06:07PM On Sat, 2020-01-04, Öö Tiib wrote: > semantic analysis of text) to computer science where it now means > any kind of deserializations? I am last from whom to ask extent of > modern English anyway. I'm not an authority either. I always assumed parsing meant reading any kind of data, deciding if it matches the parser's language, and if it does, offering the "pieces" in a helpful way to the next step of processing. E.g. yacc is a parser generator, but in my mind so is scanf(). (And as background: I know for sure I was taught in computer science that "language" is anything with a syntax and (I suppose) semantics. It doesn't have to be Turing-complete or anything.) > for raster picture). Then I use json for everything for what I don't > have such format. That might result with lot of files that I prefer > to zip into one file in Open Document Format style. We probably solve different kinds of problems; I tend to do things which fit in Unix pipelines. /Jorgen -- // Jorgen Grahn <grahn@ Oo o. . . \X/ snipabacken.se> O o . |
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