Data dodania Pytanie
2016-12-23 16:12 Why is this SSE code 6 times slower without VZEROUPPER on Skylake? »
I've been trying to figure out a performance problem in an application and have finally narrowed it down to a really weird problem. The following piec...
(2) odpowiedzi
2016-12-23 14:12 SQL query takes more than an hour to execute for 200k rows »
I have two tables each with around 200,000 rows. I have run the query below and it still hasn't completed after running for more than an hour. What co...
(3) odpowiedzi
2016-12-22 21:12 TPL - ExecutionDataflowBlockOptions defined BoundedCapacity degradetes performane »
Is there any way how to limit performance degradation with TPL throttling? I have a complicated pipeline of components and trying to limit a memory r...
(1) odpowiedzi
2016-12-22 11:12 Caching Pattern for Fetching Collections »
Is there a caching strategy/pattern that can be used for fetching multiple items, where only some may be cached? Does it make sense to use a cache in...
(0) odpowiedzi
2016-12-22 09:12 When should streams be preferred over traditional loops for best performance? Do streams take advantage of branch-prediction? »
I just read about Branch-Prediction and wanted to try how this works with Java 8 Streams. However the performance with Streams is always turning out...
(5) odpowiedzi
2016-12-21 16:12 Java vs C# speed comparison in path search algorithm »
Firstly I'm not sure if this is the right place to post this question, so if I am wrong, please, move it. Thanks. I had an assignment to compare same...
(0) odpowiedzi
2016-12-21 11:12 Multithreaded Files Reading »
I need to read / parse a large binary file (4 ~ 6 GB) that comes in fixed chunks of 8192 bytes. My current solution involves streaming the file chunks...
(2) odpowiedzi
2016-12-21 10:12 How to parse files that cannot fit entirely in memory RAM »
I have created a framework to parse text files of reasonable size that can fit in memory RAM, and for now, things are going well. I have no complaints...
(6) odpowiedzi
2016-12-20 20:12 Matrix multiplication speed issues »
I am investigating how cache misses influence speed of computation. I know there are many algorithms better for multiplying two matrices (even simple ...
(0) odpowiedzi
2016-12-20 04:12 Is List<Item> faster than List? »
I am developing a Java application with many List-s and procedures and I need it to execute very fast. I would like to know when I specify the type el...
(4) odpowiedzi
2016-12-20 01:12 Implementing a Thread Array in Matrix »
My assignment is to make a project that takes the inputted dimensions of two matrixes and have the user select the operation he wishes to perform on t...
(2) odpowiedzi
2016-12-19 15:12 Does the compiler optimize references to constant variables? »
When it comes to the C and C++ languages, does the compiler optimize references to constant variables so that the program automatically knows what val...
(3) odpowiedzi
2016-12-19 14:12 how to improve performance on inserting a lot of features into a map with leaflet.js »
With the prototype code below I'm adding a lot of features in steps into an osm. I'm loading about 8500 multipolygon features into it. Some of them ha...
(2) odpowiedzi
2016-12-19 11:12 Angular, ionic and cordova - App launch time »
I am developing an app using angular, ionic and cordova. The problem I've got is that my app takes a long time to launch (around 8-10 seconds) I'd l...
(0) odpowiedzi
2016-12-18 22:12 C++ operators overloading when having constructor conversion »
So I'm not too sure if the title well describes the problem. Essentially I'm wondering if I have a class A, which has a constructor from const & f...
(1) odpowiedzi
2016-12-18 16:12 Goroutines overhead and performance analysis when subsetting DataFrames (Gota) »
I've been working since the beginning of 2016 on implementing a Pandas/R DataFrame implementation for Go: https://github.com/kniren/gota. Recently, I...
(0) odpowiedzi
2016-12-18 06:12 Is there a faster way to add two 2-d numpy array »
Let say I have two large 2-d numpy array of same dimensions (say 2000x2000). I want to sum them element wise. I was wondering if there is a faster way...
(1) odpowiedzi
2016-12-17 23:12 Laravel 5 bulk insert with relations »
I need to bulk insert lots of data to mysql. Around 500k rows, with relations (hard part) in Laravel 5.3 Tables are vehicles, users and user_vehicle ...
(2) odpowiedzi
2016-12-17 22:12 Why is Julia allocating so much memory? »
I am trying to write a fast coordinate descent algorithm for solving ordinary least squares regression. The following Julia code works, but I don't u...
(2) odpowiedzi
2016-12-17 20:12 Fast extraction of chunks of lines from large CSV file »
I have a large CSV file full of stock-related data formatted as such: Ticker Symbol, Date, [some variables...] So each line starts of with the s...
(3) odpowiedzi
2016-12-16 20:12 Most efficient way to forward-fill NaN values in numpy array »
Example Problem As a simple example, consider the numpy array arr as defined below: import numpy as np arr = np.array([[5, np.nan, np.nan, 7, 2], ...
(2) odpowiedzi
2016-12-16 14:12 React Stateless components - performance and PureRender »
Everyone says that it uses stateless components will improve application performance. I noticed, however, that the use of stateless component in the w...
(1) odpowiedzi
2016-12-16 09:12 Scala generic math function for Int and BigInt with @specialized(Int) »
I'm new to scala and I wonder whether it is possible to define generic math function that works with both BigInt and Int and in the case of Int the ar...
(1) odpowiedzi
2016-12-16 02:12 Why Enum.map is more efficient than Enum.count in Elixir? »
I've found that counting with Enum.map |> Enum.sum works much faster than Enum.count. But why is not the built-in count function efficient? Compar...
(1) odpowiedzi
2016-12-15 16:12 Performace of multi-thread webbrowser control in ASP.NET Application »
We have a .aspx page to programmatically load page content of up to 5 urls and check each for a keyword. The following code is working but need to imp...
(0) odpowiedzi
2016-12-15 09:12 R-function which makes use of parallel programming (pdredge, R-package MuMIn) is very slow within another function »
I am using the function pdredge (i.e. model averaging using parallel computing) from package MuMIn succesfully. Utilizing more cores speeds up the tas...
(0) odpowiedzi
2016-12-15 00:12 Why is Arrays.equals(char[], char[]) 8 times faster than all the other versions? »
Short Story It seems that Arrays.equals(char[], char[]) is somehow about 8 times faster than all the other variants. If the performance of your ap...
(3) odpowiedzi
2016-12-14 15:12 How to efficiently perform double/int64 conversions with SSE/AVX? »
SSE2 has instructions for converting vectors between single-precision floats and 32-bit integers. _mm_cvtps_epi32() _mm_cvtepi32_ps() But there ar...
(2) odpowiedzi
2016-12-14 10:12 Need for fast data demuxing in C# by using multi-threading, AVX, GPU or whatever »
I have a pretty simple function that demultiplex data acquired from a board. So data comes by frames, each frame made up by multiple signals, as a 1-d...
(2) odpowiedzi
2016-12-14 09:12 Insert Into From Select Performance SQL Server »
I created a query in which I insert to a empty table the result of a select from other table. This select itself takes ~20 minutes (30 M Rows, 120 Co...
(2) odpowiedzi
2016-12-13 20:12 Branchless internal merge slower than internal merge with branch »
I recently asked a question on Code Review to review a sorting algorithm named QuickMergeSort. I won't get in the details, but at some point the algor...
(1) odpowiedzi
2016-12-13 20:12 Is it possible to `inline` a `method`? »
I've done some cursory reading on inlining declamations and read up on the relevant CLHS pages, but can't easily see an explicit answer. Is it reason...
(1) odpowiedzi
2016-12-13 09:12 Compressing efficiency »
There is a task to save data in some local storage or for network transmission. Data are stored in plain object form (key-value pairs). With the aim t...
(2) odpowiedzi
2016-12-12 22:12 Shifting row values by lag value in another column »
I have a rather large dataset and I am interested in "marching" values forward through time based on values from another column. For example, if I hav...
(1) odpowiedzi
2016-12-12 15:12 Low Performance of a factorial function written in Clojure »
I am new to Clojure. In experimenting with it I wrote I function to calculate the n!. My Clojure code is as follows: (defn factorial [n] (red...
(3) odpowiedzi