optimization

问题 In my application I am using the following means to render/generate the views to a view pager. Yes it works fine and as expected. Note :- But here I have seen that this method has to put a lot of effort in terms of Android resources ( associated with the device). I want to find out any optimized way to do the same. Is there is any? Suggest me or the above is good ? class MyActivity extends Activity{ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState)

问题 In my application I am using the following means to render/generate the views to a view pager. Yes it works fine and as expected. Note :- But here I have seen that this method has to put a lot of effort in terms of Android resources ( associated with the device). I want to find out any optimized way to do the same. Is there is any? Suggest me or the above is good ? class MyActivity extends Activity{ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState)

问题 This post says that a += b is the equivalent of a = new StringBuilder() .append(a) .append(b) .toString(); Let's say I have this code: public class MultiThreadingClass extends SomeThirdPartyClassThatExtendsObject{ public void beginmt(String st) throws IOException { //st is a thread number st = new File("c:\\somepath").getCanonicalPath()+"\\"+st; System.out.println(st); } } Assume that beginmt runs multiple times simultaneously (with thread numbers 1 to 15500) on a single instance of

问题 Many modern programming languages have short-circuit boolean evaluation such as the following: if (x() OR y()) If x() returns true, y() is never evaluated. Does SQL on modern DBMS (SQL Server, Sybase, Oracle, DB2, etc) have this property? In particular if the left side of the boolean statement is a boolean constant, will it be short circuited? Related: Do all programming languages have boolean short-circuit evaluation? 回答1: Yes and no. (Below refers to SQL Server exclusively) Some operators

问题 My latest project is using a javascript framework (jQuery), along with some plugins (validation, jquery-ui, datepicker, facebox, ...) to help make a modern web application. I am now finding pages loading slower than I am used to. After some js profiling (thanks VS2010!), it seems a lot of the time is taken processing inside the framework. Now I understand the more complex the ui tools, the more processing needs to be done. The project is not yet at a large stage and I think would be average

问题 I am building (my first...) MatLab program, it needs to differentiate an equations symbolically and then use this solution many many times (with different numeric inputs). I do not want it to recalculate the symbolic differentiation every time it needs to put in a new set of numeric values. This would probably greatly add to the time taken to run this program (which - given its nature, a numeric optimiser, will probably already be hours). My question is how can I structure my program such

问题 can anyone help me optimalize code for reading standard input. Here it is what I have now: unsigned char *msg; size_t msgBytes = 0; size_t inputMsgBuffLen = 1024; if ( (msg = (unsigned char *) malloc(sizeof(unsigned char) * inputMsgBuffLen) ) == NULL ) { quitErr("Couldn't allocate memmory!", EXIT_FAILURE); } for (int c; (c = getchar()) != EOF; msgBytes++) { if (msgBytes >= (inputMsgBuffLen)) { inputMsgBuffLen <<= 1; if ( ( msg = (unsigned char *)realloc(msg, sizeof(unsigned char) *

问题 This question already has answers here : performance of unsigned vs signed integers (12 answers) Closed 2 years ago . I have been reading through the Optimizing C++ wikibook. In the faster operations chapter one of the advice is as follows: Integer division by a constant When you divide an integer (that is known to be positive or zero) by a constant, convert the integer to unsigned. If s is a signed integer, u is an unsigned integer, and C is a constant integer expression (positive or

问题 This question already has answers here : performance of unsigned vs signed integers (12 answers) Closed 2 years ago . I have been reading through the Optimizing C++ wikibook. In the faster operations chapter one of the advice is as follows: Integer division by a constant When you divide an integer (that is known to be positive or zero) by a constant, convert the integer to unsigned. If s is a signed integer, u is an unsigned integer, and C is a constant integer expression (positive or

问题 This question already has answers here : Why are Python Programs often slower than the Equivalent Program Written in C or C++? (8 answers) Closed 6 years ago . simply run a near empty for loop in python and in C++ (as following), the speed are very different, the python is more than a hundred times slower. a = 0 for i in xrange(large_const): a += 1 int a = 0; for (int i = 0; i < large_const; i++) a += 1; Plus, what can I do to optimize the speed of python? (Addition: I made a bad example here