ibeacon precision

In the last two years, the word "precision marketing" has swept through the water, and businesses of all sizes are like catching strawsLike to seize this lifeline. As everyone knows, in order to bring the revolutionary marketing methods, precision marketing Alsois a double-edged sword, blindly use or mandatory recommendation often leads to counterproductive marketing effect.At present, the problem of

Recall and precision I. query accuracy and precision are currently relatively reasonable indicators for measuring the search results.Query completion rate = (retrieved information volume/total amount of information in the system) * 100%Precision = (the amount of retrieved information/total amount of retrieved information) * 100%The former is to measure the abili

High precision This thing is really a long time did not write, after many years, from Pascal to C + +, the code style has also changed Re-edited (after Pan guidance.) I think it's much better than I wrote before. Thought to simply write a small tutorial, I hope beginners can have some harvest ~ ~ I. High-precision arithmetic thought High precision this thing in

From: http://blog.csdn.net/walkingman321/article/details/6133171 This article analyzes the implementation of hrtimer in linux2.6.29. In linux2.6, a new timer hrtimer is implemented. Unlike the traditional timer's time wheel algorithm, hrtimer uses the red-black tree algorithm. Hrtimer can be configured with high precision and common precision. The implementation of hrtimer in a single CPU system and multip

CPU speed (MHz) and high precision latency (microsecond) (Browsing 20979 times) Victor Chen, (C ++ fans) I. High-Precision latency is the basis of CPU speed measurementWindows has a very high-precision timer in microseconds, but different systems have different timer frequencies, which may be related to hardware and operating systems. You can use the API functi

JavaScript has only one numeric type number, and all numbers in JavaScript are represented in the IEEE-754 standard format. The problem with the precision of floating-point numbers is not JavaScript-specific, because some decimals are infinite in binary representations of digits. Decimal binary0.1 0.0001 1001 1001 1001 ...0.2 0.0011 0011 0011 0011 ...0.3 0.0100 1100 1100 1100 ...0.4 0.0110 0110 0110 0110 ...0.5 0.10.6 0.1001 1001 1001 1001 ...So for

The float and double data are single and double, and their values are 3.4E+10 minus 38 times to 3.4E+10 of 38, and 1.7E+10 minus 308 times to 1.7E+10 of the 308. So for float, only 6-7 digits of the effective number, how can be loaded up to 3.4*10^ (-38) Such a large number? Similarly, 15-16-bit double type, also cannot install 1.7*10^ (-308) so large number ah? Answer: float 6-7 refers to number of digits of a valid number (precision), not numeric

oracle number type precision, scale range Number (p,s) P:1---38 S: -84---127 valid digits : From the left of the first number not 0, to the end of all numbers, the decimal point and minus sign are not counted in the number of significant digits. NBSP p>0, s 3 case: 1. NBSP;S>0NBSP to the right s bit of the decimal point and rounded . Then verify that the valid digits are ; ZWF. Yudong>create table T_n (ID number (5,2)); table

If I ask you 0.1 + 0.2 equals how many? You may send me a supercilious eye, 0.1 + 0.2 = 0.3 Ah, that still ask? Even the kindergarten children will answer such a childish question. But you know, the same problem is in the programming language, maybe it's not as simple as it might seem.Don't believe it? Let's look at a section of JS first. var NumA = 0.1;var NumB = 0.2;Alert (NumA + numB) = = 0.3); The execution result is false. Yes, when I first saw this code, I took it for granted that it was

This article assumes that you are familiar with the C + + and Win32 APIs Profile The time stamp (Timestamp) obtained from Windows NT has a maximum accuracy of 10 to 15 milliseconds depending on the hardware you are using. However, sometimes when you need time to label frequent events, getting higher accuracy is more satisfying. For example, what if you want to deal with threads, or do some other task at intervals of not less than 10 milliseconds? For better accuracy, the recommended approach i