processing-efficiency

问题 I have defined a class Results that is supposed the hold the results of a certain operation. I perform this operation 10.000 times and add the result to the result class. Since this operation is slow, to prevent data loss, I save the temporary results every time (that is, I call save('tempResults.mat', 'obj') inside a method in my class) The issue is that I write from scratch the whole class every time. But by the 5000th time, the class is already ~ 1 Gb big. It is unusable to write 1 Gb of

问题 Some parameters have been described in the Advanced computer architecture book by Hwang, e.g Speedup, Efficiency, Redundancy, Utilization and Quality as shown in the picture below. I understand all and partially understand the last parameter, quality. The question is, why quality has inverse relationship with the redundancy. As said, redundancy shows the matching between software parallelism and the hardware. For example, one processor runs one unit instruction, therefore, O(1)=1. By O(n) we

问题 Let's say I have these 3 integer arrays: int[] a = {1, 2, 3}; int[] b = {3, 4, 5}; int[] c = (2, 1, 3}; I'm looking for the most efficient code that will consider a the same as c (because they contain the same numbers but in a different order), but consider a different from b, and b different from c. I know I can sort them all so that c becomes {1, 2, 3} and therefore the same as a, but I'm comparing hundreds of arrays with more than three numbers each and I don't want my program to sort each

问题 Let's take some CSS properties and place them randomly in our CSS file: outline pseudo-elements Color Properties Background and Border Properties Box Properties Flexible Box Layout Text Properties Text Decoration Properties Font Properties Writing Modes Table Properties Lists Animation If you want to maximize rendering speed, in what order should you list your CSS properties? 回答1: The short answer is: it doesn't matter. To elaborate on that: Say you would implement a browser 1 and get to the

问题 I have looked up online and all I seem to find are answers related to the question of "how does Node benefit from running in a multi core cpu?" But. If you have a machine with just one core, you can only be running one process at any given time. (I am considering task scheduling here). And node uses a single threaded model. My question: is there any scenario in which it makes sense to run multiple node processes in one core? And if the process is a web server that listens on a port, how can

问题 From anybody with real experience, how do LIKE queries perform in MySQL on multi-million row tables, in terms of speed and efficiency, if the field has a plain INDEX? Is there a better alternative (that doesn't filter results out, like the FULLTEXT 50% rule) for perform database field searches on multi-million row tables? EXAMPLE: Schema (comments table) id (PRIMARY) title(INDEX) content time stamp Query SELECT * FROM 'comments' WHERE 'title' LIKE '%query%' 回答1: From anybody with real

问题 I apologize in advance if this has a simple answer somewhere. It seems like the kind of thing that would, but I can't seem to locate it in the help files, by searching SO, or by Googling. I'm working with some datasets that are several GB right now. It's enough to fit in memory on one of the cluster nodes I have access to, but takes quite a bit of time to load. For many debugging/programming activities with this data, I don't need the entire file loaded, just the first few thousand

问题 This is the userform created by me. Then ,it is used as an input platform .There are some different tables ,eg.2016 ,2017.... The logic of that save button is to search the Year(Date) that user input and location the right worksheet. Then , it will find the last row of that worksheet . For example , the last row is row 1000. The first row of the userform will save on row 1001.The second row of the userform will save on row 1002.... Question However , when i test in the real excel file , the

问题 What is the most efficient (or Pythonic way) to carry out a double for loop as in below (I know how to do this for list comprehension but not for a single object to be returned): for i in range(0, 9): for j in range(0, 9): if self.get(i)[j] == "1": return (i, j) 回答1: >>> next(((i, j) for i in range(0, 9) for j in range(0, 9) if self.get(i)[j] == "1"), None) This will return None if nothing is found. See the documentation for next. The first parameter is a generator. You need this if you

问题 This is the question: There are N boys and N girls. Only a boy and a girl can form a dancing pair (i.e. no same sex dancing pairs are allowed). The only other condition in making pairs is that their absolute difference in height should be less than or equal to K. Find the maximum number of pairs that can be formed so that everyone has a unique partner. I want to improve my algorithm to take less time.. first see the code: //k is the maximum difference between pairs int k = 5; ArrayList