Data dodania Pytanie
2017-03-07 06:03 Pandas column indexing for searching? »
In relational database, we can create index on columns to speed up querying and joining on those columns. I want to do them same thing on pandas dataf...
(1) odpowiedzi
2017-03-06 17:03 How can several comparisons be slower than some calculations? »
We were developing a piece of code that would check whenever the user should not be allowed to get into a sector within a time period, one of my colle...
(2) odpowiedzi
2017-03-06 15:03 Fastest way to cast all dataframe columns to float - pandas astype slow »
Is there a faster way to cast all columns of a pandas dataframe to a single type? This seems particularly slow: df = df.apply(lambda x: x.astype(np.f...
(2) odpowiedzi
2017-03-06 08:03 Why is reading multiple files at the same time slower than reading sequentially? »
I am trying to parse many files found in a directory, however using multiprocessing slows my program. # Calling my parsing function from Client. L =...
(2) odpowiedzi
2017-03-05 12:03 Is it more efficient to use events when another class variable changes than accessing the variable directly? What about safety? What about properties? »
I'm simplifying the situation as much as I can: class 1: public class GameFlowManager { public float worldSpeed; } class 2: public class Clo...
(1) odpowiedzi
2017-03-05 05:03 JVM garbage collection - tracing live objects in young generation »
While collecting the young generation memory, JVM collectors scan only those root objects (obejcts in the heap directly accessible from the root set) ...
(2) odpowiedzi
2017-03-05 00:03 C# Excel Interop Slow when looping through cells »
I am trying to extract all text data from an Excel document in C# and am having performance issues. In the following code I open the Workbook, loop ov...
(5) odpowiedzi
2017-03-04 23:03 Specializing related polymorphic functions without inlining »
Here's a minimal example reproducing a real problem I'm working on: One library module: module Lib where class H h where hash :: (S s)=> s -&g...
(0) odpowiedzi
2017-03-04 09:03 could sum be faster on lists »
This is somehow a follow-up to this question So first, you'll notice that you cannot perform a sum on a list of strings to concatenate them, python t...
(3) odpowiedzi
2017-03-04 08:03 Why is my C++ disk write test much slower than a simply file copy using bash? »
Using below program I try to test how fast I can write to disk using std::ofstream. I achieve around 300 MiB/s when writing a 1 GiB file. However, ...
(4) odpowiedzi
2017-03-03 22:03 Why is `std::array` slower than `std::vector`? »
Note: This has only been confirmed in an online IDE, tests on my own laptop do not confirm this. Let us test the performance of the two containers wi...
(0) odpowiedzi
2017-03-03 18:03 How to get faster pairwise distance and vector calculations in Julia 0.5 compared to Matlab2016b? »
I am running a program that requires repeated use of pairwise distance calculations across a collection of points in 2D and then calculating the vecto...
(4) odpowiedzi
2017-03-03 04:03 Java method call performance »
I have this piece of code doing Range Minimum Query. When t = 100000, i and j are always changed in each input line, its execution time in Java 8u60 i...
(5) odpowiedzi
2017-03-02 21:03 Why are these matrix transposition times so counter-intuitive? »
The following example code generates a matrix of size N, and transposes it SAMPLES number of times. When N = 512 the average execution time of the tra...
(1) odpowiedzi
2017-03-02 16:03 How much faster is implicit expansion compared with bsxfun? »
As commented by Steve Eddins, implicit expansion (introduced in Matlab R2016b) is faster than bsxfun for small array sizes, and has similar speed for ...
(1) odpowiedzi
2017-03-02 16:03 Why is std::fill(0) slower than std::fill(1)? »
I have observed on a system that std::fill on a large std::vector<int> was significantly and consistently slower when setting a constant value 0...
(1) odpowiedzi
2017-03-01 20:03 Python: How to make this color thresholding function more efficient »
I wrote an adaptive color thresholding function in Python (because OpenCV's cv2.adaptiveThreshold didn't fit my needs) and it is way too slow. I've ma...
(1) odpowiedzi
2017-03-01 16:03 Why is this code slower when the array size is even? »
Warning: Actually it is not due to power of 2 but parity. See the EDIT section. I have found a code which shows quite a strange behaviour. The co...
(2) odpowiedzi
2017-03-01 12:03 Java hashmap vs hashset performance »
I have a file consisting of 7.6M lines. Each line is of the form: A,B,C,D where B,C,D are values that are used to calculate a level of importance for ...
(3) odpowiedzi
2017-02-28 22:02 An alternative to two AVL trees »
I currently have data that I need sorted in two different ways, from a time and space complexity PoV, is there any alternative to maintaining two tree...
(3) odpowiedzi
2017-02-28 19:02 Why does my code run quicker on my phone than my laptop? »
I'm beginning to learn python and I've just finished my first project, which was the collatz sequence, which is "If n is even, divide it by 2 to get n...
(0) odpowiedzi
2017-02-28 10:02 Can the Java VM optimise away a Builder entirely? »
I was discussing performance implications of using the Builder pattern within Java with a colleague and while doing research I came across an interest...
(0) odpowiedzi
2017-02-27 14:02 Avoiding virtual function calls in a computational graph »
I'm using a DAG (directed acyclic graph) to represent and evaluate expressions; each node represents an operation (+, -, /, *, accumulate, etc...) and...
(1) odpowiedzi
2017-02-27 11:02 Speed up the lookup procedure »
I have two tables: coc_data and DT. coc_data table contains co-occurrence frequency between pair of words. Its structure is similar to: word1 word...
(1) odpowiedzi
2017-02-27 03:02 Nav menu slider over ListView performs badly »
I have written a JS application with a nav menu that slides into view using a simple CSS transition of the transform property. It performs well on De...
(0) odpowiedzi
2017-02-26 17:02 Why is it faster to call an abstract method than an interface method in .NET? »
I have an interface I, an abstract class A, concrete classes for both of those, and a concrete class C to use as a baseline. interface I { void D...
(0) odpowiedzi
2017-02-26 17:02 Fastest way to search for 2 different values in assembly »
I want so search an assembly buffer for one of two given values, that differs only by one bit. let's say 0xfefefeffand 0xfefefefe (In other words - th...
(1) odpowiedzi
2017-02-26 00:02 pandas read_csv converters performance issue »
Description While reading large csv files (several million rows of mixed data), I used the converters parameter of pandas' read_csv method to conveni...
(1) odpowiedzi
2017-02-25 15:02 Dealing with heavy profiling of execution times in C++ »
I'm currently working on a scientific computing project involving huge data and complex algorithms, so I need to do a lot of code profiling. I'm curre...
(2) odpowiedzi
2017-02-25 12:02 Bluebird promisify vs promisifyAll Performance compare when want to promisification of one method from module »
I want to know performance difference between bluebird promisify vs promisifyAll. I have tried performance test of bluebird promisify and promisifyAl...
(1) odpowiedzi
2017-02-25 08:02 How do I find top 10 or top few CPU intensive threads created by Java process in Linux? »
How do I find top 10 or top few CPU intensive thread stack traces created by Java process in Linux ? I would like to know how much time spent as well ...
(2) odpowiedzi
2017-02-24 15:02 Are there performance implications when using ArrayList.get() many times per iteration? »
For Android development in general, is it more expensive to do the following: (Example 1) for(int x=0; x < largeObjectCollection.size(); x++){ ...
(4) odpowiedzi
2017-02-24 13:02 When to create a local variable and when to call an objects method? »
Here is a scenario. Object A has a method which receives an object. There are 2 methods. Both are doing essentially the same thing. randomCheck1()...
(4) odpowiedzi
2017-02-24 00:02 Performance difference between JavaScript created inline styles and JavaScript created stylesheets »
I want to dynamically style all elements of a given selector in my DOM. I see more or less two ways about it. For the example below I'll use a p eleme...
(2) odpowiedzi
2017-02-23 16:02 How to, simply, wait for any layout in iOS? »
Before beginning note that this has nothing to do with background processing. There is no "calculation" involved that one would background. Only UIKi...
(6) odpowiedzi