performance

问题 I am trying to speed up a code that is using Numpy's where() function. There are two calls to where() , which return an array of indices for where the statement is evaluated as True , which are then compared for overlap with numpy's intersect1d() function, of which the length of the intersection is returned. import numpy as np def find_match(x,y,z): A = np.where(x == z) B = np.where(y == z) #A = True #B = True return len(np.intersect1d(A,B)) N = np.power(10, 8) M = 10 X = np.random.randint(M,

问题 Example: `1. No of Threads = 100 Ramp-up time = 20, means every 1 second = 5 requests will be processed. Loop Count =1 In the same time: If i will do like below No of Threads = 100 Ramp-up time = 1, Loop Count =1` And put Synchronization Timer : No of Simulated user to group = 5. In this case as well, J meter process 5 requests at one time. So what is the different logic between the above 2 concepts. 回答1: Considering case 1 where the Number of threads = 100, Ramp-up time = 20 and loop count

问题 I noticed if we know there is good chance for control flow is true or false, we can tell it to compiler, for instance, in Linux kernel, there are lots of likely unlikely , actually impled by __builtin_expect provided by gcc , so I want to find out how does it work, then checked the assembly out there: 20:branch_prediction_victim.cpp **** if (array_aka[j] >= 128) 184 .loc 3 20 0 is_stmt 1 185 00f1 488B85D0 movq -131120(%rbp), %rax 185 FFFDFF 186 00f8 8B8485F0 movl -131088(%rbp,%rax,4), %eax

问题 I re-wrote a query to reduce the time it takes to pick the records. But still I see that there is a small tuning that needs to be done in the decode line as the cost is high. Can someone please let me know if the same query can be re-written without the decode functionality? The purpose of removing the decode function would be to use the index in v_id column. What I have tried so far. Tried creating a function index (Knowing that bind variables cannot be used) and it failed. Have tried using

问题 Problem: When using broadcasting, rather than broadcasting scalars to match the arrays, the vectorized function is instead, for some reason, shrinking the arrays to scalars. MWE: Below is a MWE. It contains a double for loop. I am having trouble writing faster code that does not use the for loops, but instead, uses broadcasting/vectorized numpy. import numpy as np def OneD(x, y, z): ret = np.exp(x)**(y+1) / (z+1) return ret def ThreeD(a,b,c): value = OneD(a[0],b[0], c) value *= OneD(a[1],b[1]

问题 Problem: When using broadcasting, rather than broadcasting scalars to match the arrays, the vectorized function is instead, for some reason, shrinking the arrays to scalars. MWE: Below is a MWE. It contains a double for loop. I am having trouble writing faster code that does not use the for loops, but instead, uses broadcasting/vectorized numpy. import numpy as np def OneD(x, y, z): ret = np.exp(x)**(y+1) / (z+1) return ret def ThreeD(a,b,c): value = OneD(a[0],b[0], c) value *= OneD(a[1],b[1]

问题 I'm trying to force sql server to make a short circuit OR comparison on some fields. On the left side of the Or I have a simple variable comparison and on the right side I have a pretty 'heavy' subquery. WHERE (@Var = 'DefaultValue' ) OR Exists(select * from atable) Is there any way to only execute the right side of the or statement if the first statement is false. I've tried case and if else statements but can't find any working syntax. I'm using a MS SQL server 回答1: You can't do what you

问题 So here's the situation: I have millions, possibly billions, of strings that I am trying to parse and put into a sorted structure, lets say I have 5,000,000 strings. I'm trying to write a fast program that can put all of these strings from an unsorted vector into an ordered data structure that can also search the structure fast, thus the reasoning for the AVL tree (which eventually I plan to use a hash table of a-z for even faster lookup, but that comes later). I get all of the strings into a

问题 Context I'm learning how to code in javascript consistently, readably and maintainably. I found nothing about the order of declaration of variables and functions. Example: var example = { A: function() { var a, b, c; }, B: function() { var a, b, c; }, C: function() { var a, b, c; } } Questions Alphabetically is the best one ? Is that the order can improve the speed of code execution ? 回答1: I use jslint to check the code quality. It can be integrated with Visual Studio and a lot of other stuff

问题 Context I'm learning how to code in javascript consistently, readably and maintainably. I found nothing about the order of declaration of variables and functions. Example: var example = { A: function() { var a, b, c; }, B: function() { var a, b, c; }, C: function() { var a, b, c; } } Questions Alphabetically is the best one ? Is that the order can improve the speed of code execution ? 回答1: I use jslint to check the code quality. It can be integrated with Visual Studio and a lot of other stuff