boost-multi-array


Fastest method of accessing elements in Boost MultiArray

偶尔善良 提交于 2020-01-24 22:53:04
问题 What is faster - accessing elements of a multiarray using element selection operator, or traversing over the multiarray using iterators? In my case, I need to do a full pass over all elements of multiarray each time. 回答1: The fastest way to access every element of a boost::multi_array is via data() and num_elements() . With data() you gain access to the underlying raw storage (a contiguous block that contains the array‘s data) so there isn't need for multiple index calculations (consider also

Iterating over the dimensions of a boost::multi_array

断了今生、忘了曾经 提交于 2020-01-04 02:46:34
问题 I'm trying to write some dimension-independent code for a template class in c++, using a boost::multi_array (though if other containers/data structures are better at this, I'd be happy to hear about it). Given a dimension, I would like to iterate over the full range of every other dimension, returning a 1d view along the selected dimension. This is fairly straightforward, or at least it appears to be from the boost documentation. What I can't figure out how to do is iterate the selected

pointers to a class in dynamically allocated boost multi_array, not compiling

荒凉一梦 提交于 2019-12-23 08:28:13
问题 I am pretty new to C++ with Boost. I want an object of class "world" to have an array named "chunk" of type "octreenode". Previously I had an ordinary one-dimensional array, and this worked fine. Now I'm trying to move to using a 3D array with Boost's multi_array functionality, and I'm really not sure what I'm doing wrong. Simplified code: class world { public: typedef boost::multi_array<octreenode, 3> planetchunkarray; // a boost_multi for chunks typedef planetchunkarray::index index;

Segmentation fault on boost::multi_array

旧时模样 提交于 2019-12-20 05:29:29
问题 The following code gives a segmentation fault: #include <iostream> #include <fstream> #include "binItr.h" #include <boost/multi_array.hpp> using namespace std; int main(){ const char * xifile = "results/feretxiG1155V0P5T231K10.bin"; const uint pSize = 5; const uint T = 231; ifstream xiFileId(xifile, ios::binary); typedef boost::multi_array<uint, 2> array_type; array_type xi(boost::extents[T][pSize + 1]); //the ii_t class in the following line is taken from http://stackoverflow.com/questions

Segmentation fault on boost::multi_array

大憨熊 提交于 2019-12-20 05:29:09
问题 The following code gives a segmentation fault: #include <iostream> #include <fstream> #include "binItr.h" #include <boost/multi_array.hpp> using namespace std; int main(){ const char * xifile = "results/feretxiG1155V0P5T231K10.bin"; const uint pSize = 5; const uint T = 231; ifstream xiFileId(xifile, ios::binary); typedef boost::multi_array<uint, 2> array_type; array_type xi(boost::extents[T][pSize + 1]); //the ii_t class in the following line is taken from http://stackoverflow.com/questions

Container for boost::multi_array of same type but with different dimentionality

北战南征 提交于 2019-12-18 09:09:44
问题 What i need is to create a class that can hold boost::multi_array of same type but with different dimentions assume there are one or more such arrays of Double boost::multi_array<double, 2> array_2d; //2D array boost::multi_array<double, 3> array_3d; //4D array boost::multi_array<double, 4> array_4d; //5D array etc... i need a container class that can hold all of the above types that is able to deference the correct type later when needed something like GenericArray<double> arr; arr.IsEmpty()

how to traverse a boost::multi_array

落花浮王杯 提交于 2019-12-17 16:26:35
问题 I have been looking into the boost::multi_array library in search of an iterator that allows you to traverse the whole multi_array in a single for loop. I don't think there is any such iterator in that library. (The iterators that are found there let you traverse a single dimension of the multi_array) Am I wrong? If not, is there any library that defines such an iterator? Entering into details, I'd like to write something like: boost::multi_array< double, 3 > ma(boost::extents[3][4][2]); for(

How do you assign a boost::indices in a variable?

百般思念 提交于 2019-12-13 18:52:12
问题 I am trying to store a boost::indices in a variable. From what I can gather, this produces an index_gen type. However, index_gen seems to be templated in boost::detail , but the template parameters are not exposed to multi_array::index_gen , and they seem to default to <0,0> , which produces the error you'll see below: I have tried the following: #include "boost/multi_array.hpp" int main() { typedef boost::multi_array<double, 3> array_type; using IndexType = boost::array<array_type::index, 3>

Why is `index_gen` in `multi_array` a `boost::detail::multi_array::index_gen<0,0>`

微笑、不失礼 提交于 2019-12-11 14:01:35
问题 This discussion has let to another question. It seems that index_gen in multi_array (a.k.a. boost::multi_array::index_gen ) is set to boost::detail::multi_array::index_gen<0,0> , where I would have expected it to be boost::detail::multi_array::index_gen<Dim,Dim> where Dim is the template parameter of multi_array . Can anyone explain why this <0,0> type is used instead? 来源: https://stackoverflow.com/questions/35633531/why-is-index-gen-in-multi-array-a-boostdetailmulti-arrayindex-gen0-0

Boost MultiArrays performance is poor

做~自己de王妃 提交于 2019-12-11 10:07:54
问题 I noticed that my boost mutiarrays were performing very badly compared to STL Vector. I came upon this question asked earlier, where the most liked answer stated that 1) Boost is nearly as fast as native array 2) You need to change the order in which you access your data elements to get the best performance out of Boost MultiArray. Also, that you need to run in Release mode, and not Debug. Well, I did all that, and yet the performance of my MultiArrays is pretty shabby. I am posting my code

工具导航Map