Data dodania Pytanie
2017-07-27 18:07 Fast way to check if string is `mostly` capital »
I'm writing a bot in C# for a chat room and I want to detect if a message contains too many capital letters. A message contains too many capital lette...
(2) odpowiedzi
2017-07-27 18:07 SPARQL Speed up federated query »
I have my own dataset and I want to perform a federated query in SPARQL. Here is the query: PREFIX : <http://myURIsNamespace#> PREFIX wd: <h...
(1) odpowiedzi
2017-07-27 11:07 2 AtomicReferences can false share? »
when i have Object a; Object b; i have false sharing this way i dont @Contended Object a; Object b; but if i have final AtomicReference<Ob...
(1) odpowiedzi
2017-07-26 17:07 Is there a downside to a significant overestimation in a reserve()? »
Let's suppose we have a method that creates and uses possibly very big vector<foo>s. The maximum number of elements is known to be maxElems. St...
(5) odpowiedzi
2017-07-26 12:07 Does String concatenation get optimized to use existing StringBuilders? »
I have the following code: StringBuilder str = new StringBuilder("foo"); for(Field f : fields){ str.append("|" + f); } str.append("|" + bar); Str...
(4) odpowiedzi
2017-07-26 10:07 numpy: cumulative multiplicity count »
I have a sorted array of ints which might have repetitions. I would like to count consecutive equal values, restarting from zero when a value is diffe...
(2) odpowiedzi
2017-07-25 19:07 base case and time complexity in recursive algorithms »
I would like some clarification regarding O(N) functions. I am using SICP. Consider the factorial function in the book that generates a recursive pro...
(3) odpowiedzi
2017-07-25 11:07 Why does loop alignment on 32 byte make code faster? »
Look at this code: one.cpp: bool test(int a, int b, int c, int d); int main() { volatile int va = 1; volatile int vb = 2; v...
(1) odpowiedzi
2017-07-25 10:07 Optimizing SQL by using temporary table in Oracle »
I have a data cleanup-er procedure which deletes the same data from the card rows of two tables. Both of these update statement use the same subQuery ...
(1) odpowiedzi
2017-07-24 23:07 Bit trick to detect if any of some integers has a specific value »
Is there any clever bit trick to detect if any of a small number of integers (say 3 or 4) has a specific value? The straightforward bool test(int a,...
(3) odpowiedzi
2017-07-24 21:07 How to improve Java multi-threading performance? Time efficiency of saving/loading data from NoSQL database (like Redis) vs ArrayList? »
I am evaluating an SDK and I need to cross compare ~15000 iris images stored in a gallery folder and generate the similarity scores as a 15000 x 15000...
(1) odpowiedzi
2017-07-24 17:07 Does lessening lines of code decrease load time of a project? »
I have a .NET solution which contains multiple projects with in it. Have identified some potential hot spots of the project which can be improved. E...
(4) odpowiedzi
2017-07-23 21:07 Aggregate query takes too long »
I've made a query using the aggregation framework in the latest version of MongoDB. The problem is that I can't find the way to get the result because...
(0) odpowiedzi
2017-07-23 17:07 What is faster to execute, the same statment repeated or a looped statment? »
What is faster to execute, the same statment repeated or a looped statment? Why? Repeated: printf("Hello, world!\n"); printf("Hello, world!\n"); pri...
(4) odpowiedzi
2017-07-23 13:07 Why is the performance of `while` said to be slower than `for` when iterating over an array? »
The second edition of The Rust Programming Language states the following about while loops for iterating over an array: fn main() { let a = [10, ...
(1) odpowiedzi
2017-07-22 17:07 PowerShell | Need some performance improvement »
I have written a powershell script for archival of old log files or say some output file of web application which is in TBs but the script is taking v...
(1) odpowiedzi
2017-07-22 08:07 Revolving Doors Riddle - Matlab Time-Efficient Sparse Matrix Use »
I'm running a code with many iterations using large sparse matrices. There are three lines in my code that take about 75% of the running time and I th...
(0) odpowiedzi
2017-07-22 01:07 Postgres 9.4.12 Slow queries »
I'm having slow queries with my postgres in a table with 9 million rows. Query: EXPLAIN (ANALYZE, BUFFERS) SELECT date_point, geo, alarms, status FRO...
(1) odpowiedzi
2017-07-21 22:07 Why is Task.WhenAny so slow when called many times against the same TaskCompletionSource? »
If a class has a member TaskCompletionSource<TResult> m_tcs with a long lifetime, and if Task.WhenAny is called with m_tcs.Task as one of its ar...
(1) odpowiedzi
2017-07-21 21:07 How does array access affect the performance? »
int steps = 256 * 1024 * 1024; int[] a = new int[2]; // Loop 1 for (int i=0; i<steps; i++) { a[0]++; a[0]++; } // Loop 2 for (int i=0; i<steps...
(1) odpowiedzi
2017-07-21 18:07 Is it technically possible to make Python / Ruby as performant as Common Lisp? »
It is said that Python/Ruby are conceptually close to Common Lisp. I was wondering specifically - Being said to provide high performance to modern C...
(0) odpowiedzi
2017-07-21 14:07 Why does a java collecting stream run each getter twice? »
I have a List with items, where each item is an object with a getter method I'm interested in. I want to run over the complete list to sum all those g...
(2) odpowiedzi
2017-07-20 23:07 Efficient way of slicing large image into 10x10 images (opencv) »
I have a large 2400x1300 png file that I want to slice up into 10x10 pixel ordered images and save them into a separate file. I have found multiple me...
(1) odpowiedzi
2017-07-20 15:07 Efficient method to count number of unique elements in ranges? »
I need to count number of unique elements in a set of given ranges. My input is the start and end coordinates for these ranges and I do the following....
(3) odpowiedzi
2017-07-20 09:07 Error due to Status code 409 when running jMeter script »
I'm executed the jMeter script and it returns response of 409, 404 or 500. The below is the response of one of the request: Thread Name: Thread Gro...
(1) odpowiedzi
2017-07-19 22:07 The price of rendering elements using D3 in a React application? »
I'm trying to understand how to integrate D3 and React. Specifically I'm trying to understand how using D3 to render visualizations impacts React. As ...
(1) odpowiedzi
2017-07-19 14:07 Microsoft R data ingestion is too slow »
Some time ago I wrote this question because I thought that the query was too slow but after much trial and error I found out that the problem is data ...
(0) odpowiedzi
2017-07-19 07:07 SQL - Better way to create this nested Select case query »
I have to retrieve the sum of amounts based on certain conditions. There are 2 tables 1. Stocks table 2. Payments table This is the requirement "S...
(0) odpowiedzi
2017-07-18 19:07 C# Performance on Small Functions »
One of my co-workers has been reading Clean Code by Robert C Martin and got to the section about using many small functions as opposed to fewer large ...
(1) odpowiedzi
2017-07-18 16:07 Calculate gradient only in a masked area »
I have a very large array with only a few small areas of interest. I need to calculate the gradient of this array, but for performance reasons I need ...
(1) odpowiedzi
2017-07-18 00:07 Is the VCL dramatically slower with Japanese texts? »
I'm using RAD Studio XE7 (C++ Builder). For one of my projects, the main form contains several components, like panels, buttons, labels, edit boxes, ....
(0) odpowiedzi
2017-07-17 16:07 Efficient find of first element of a vector that meets a logical condition in Matlab »
I need to find the index of the first element of a vector A that satisfies the condition A(i) <= b. I know before hand that at least one element of...
(1) odpowiedzi
2017-07-17 14:07 Table Join with limit and performance increase »
Background: I'm writing an in house SEO crawler to check our positions in google. The crawling is working brilliantly, the storage is fine, but Im now...
(2) odpowiedzi
2017-07-17 08:07 sorting version numbers stored as string in array »
Say i have an array like this: var arr = ["1.2.5", "1", "10", "2.0.4", "3.3.3.3"]; What would be the best way to sort this and get result like th...
(4) odpowiedzi
2017-07-16 14:07 How can I accurately benchmark unaligned access speed on x86_64 »
In an answer, I've stated that unaligned access has almost the same speed as aligned access a long time (on x86/x86_64). I didn't have any numbers to ...
(3) odpowiedzi