churn calculation

entry/inverted document frequency (TF/IDF)If there are now two documents as follows{"Name": "Charlie", "description": "Hunterplus Java"}{"Name": "Charles", "description": "Hunterplus web"}The following three calculations are examples of these two simple documentsFrequency of entry TFThe frequency of entry, the full term Frequency, referred to as TF, is the BOOL model residue of all the documents to carry out the entry statistics, to obtain a frequency of the square rootThis frequency refers to

When we save the floating-point number and then read the floating-point number, the result may be a little bit biased. For example: float ft1 = 20.2; (This will cause the compiler to report a warning because the decimal point defaults to Double) CString str;str.Format (_t ("%f"), FT1), when the value of FT1 is equal to 20.200001. float ft2 = 20.8; CString Str;str.Format (_t ("%f"), ft2), when the value of FT1 is equal to 20.799999.Workaround 1: Use float instead of double storage: double dt1 = 2

side, two reads + two writes are required, so the value of RAID-5 's write penalty is 4.???different RAID level of Write Penalty :??The following table lists the various RAID levels Write Penalty values:?? RAID Write penalty 0 1 1 2 5 4 6 6 10 2 ???RAID-0 : direct stripe, one write to the corresponding physical disk each t

Looking for the optimal calculation method to find the optimal calculation array method, we can't figure out that I have two arrays: PHPcode $ arr1array (array (id gt; 1, pos gt; 1), array (id gt; 2, pos gt; 2), array (to find the optimal calculation method Looking for the optimal array calculation method cannot be

Looking for the optimal calculation method to find the optimal calculation array method, we can't figure out that I have two arrays: PHPcode $ arr1 = array ('id' = gt; 1, 'pos' = gt; 1), array ('id' = g find the optimal calculation method Looking for the optimal array calculation method cannot be achieved. I have tw

mom asks you to go home for dinner, go home Luo"; long T1 = system. currenttimemillis (); For (INT I = 0; I Time spent: 4266 MS It took 4 seconds to calculate the cost. Suppose we need to compare times a day, and it takes 4 s to compare the data repeat by times. Even if we have 4 s documents, a single thread can process 15 documents in one minute, there are only 900 documents per hour and 21600 documents per day. This number is far from documents per day. How many machines and resources are

)} output formula for second-order IIR filter Y (n) = b0xn + b1xn-1 + b2xn-2-(a1xn-1 + a2xn-2) Type 1In Formula 1, A1, A2, B0, B1, and b2 are the two-order filter IIR coefficients, which determine the frequency response curve and gain of the filter. How to obtain A0, A1, A2, B0, B1, B2? For a second-order IIR filter, the standard technical indicators are as follows: 1. center frequency f0; 2. sampling frequency fs; 3. Gain dB; 4. quality factor; Based on the above technical indicators, we can de

World of Warcraft calculation formulas officially announced (taking warrior and Sunday as an example) I. Attack intensity (Attack Power, AbbreviationAP) Warrior/Paladin(Warrior/Server guard ):AP =Role level* 3 +Power* 2-20(For example, you50Level, strength is100Your attack intensityAPYes50Multiplication3Add100Multiplication2Minus20, And finally equal330Is it easy ?) Hunter/rogue:AP =Role level* 2 +Power+Agility-20 Shaman:AP =Role level* 2 +Powe

digital verification code. The six-digit address code, eight-digit birth date code, three-digit sequence code, and one-digit verification code are arranged from left to right.The address code indicates the Administrative Code of the county (city, flag, district) where the resident account of the encoding object is located. The birthdate code indicates the year, month, and day of the encoding object. The year is represented by four digits, and there is no separator between the year, month, and d

The Value Calculation Method of ken_len In the MySQL query plan, mysqlken_len Description of key_len In MySQL, you can use explain to view the path of the SQL statement, as shown below: mysql> create table t(a int primary key, b int not null, c int not null, index(b)); Query OK, 0 rows affected (0.01 sec) mysql> explain select b from t ; +----+-------------+-------+-------+---------------+------+---------+------+------+-------------+ | id | select_typ

Report a very strange issue of the IE scroll bar -- the scroll bar is abnormal when the percentage calculation width is floating point. Cause: During project creation, a table with more content than the DIV container is automatically rolled horizontally. Other browsers are normal, but the scroll bar appears when the table and the DIV width of the container are consistent under IE. 　　 I finally found the reason for my experiments for a long time. This

1-3-2. Calculation of energy storage inductance of inverted series Switching Power SupplyThe calculation method of the energy storage inductance of the inverted series switching power supply is basically the same as that of the previous "calculation of the energy storage filter inductance of the tandem Switching Power Supply". The value of the energy storage indu

The hansh value of BT seeds is calculated. Recently, I am suddenly interested in BT seeds (do not ask why) 1. BT seeds (concept) BT is a distributed file distribution protocol. Each file downloader continuously uploads downloaded data to other Downloaders while downloading. This ensures that the faster the download, the faster the upload, to implement notification download 2. How does BT download and upload files simultaneously? Starting from the file itself, the BT file contains two parts of

The previous article raised questions about field calculation. After several days of exploration, it was found that it was not difficult to write VBA. As long as the related tables and their connection relationships are established, field calculation can be easily completed. The process is as follows: 1. Create a data table under arccatalog Create the original data table: Data Data Objectid F1 F

PHP time stamp and day conversion and calculation examples, Phpunix Unix timestamps are a compact and concise way to save dates and times, a way to save the current date and time in most Unix systems, and a standard format for representing dates and times in most computer languages. Represents Greenwich Mean Time as a 32-bit integer, for example, a timestamp that represents the current time using certificate 11230499325. The UNIX timestamp is the num

DNV. PHAST. v7.01 + dnv phast safeti v6.53.1 Accident Consequence simulation and Security Risk Calculation SoftwareDNV. PHAST. v7.01 Accident Consequence simulation and Security Risk Calculation SoftwareDnv phast safeti v6.53.1DNV leak v3.2 petrochemical plant Risk AnalysisDnv phast safeti v6.51 1cd (Accident Consequence simulation, security risk calculation s

Comprehensive in-depth analysis of spark2--knowledge points, source code, Tuning, JVM, graph calculation, projectCourse View Address: http://www.xuetuwuyou.com/course/220The course out of self-study, worry-free network: http://www.xuetuwuyou.comA total of 14 chapters, 316 sections, the course from spark-related technical aspects of all-round analysis, and finally the actual project: User interactive behavior Analysis System, DMP User Portrait system,

Tagged with: Fibonacci memo recursive one Fibonacci demo RIP cache startWhy say " algorithm is the soul of the program is not too much", please see the following simple case1 Packagerecursion;2 3 ImportJava.util.HashMap;4 ImportJava.util.Map;5 6 Importorg.junit.Test;7 8 /** 9 * @author: MengxianmanTen * @creationTime: November 27, 2017 morning 9:47:51 One * @description: The simple use of the Fibonacci sequence combination memo algorithm A */ - Public classMemorandumdemo { - //

The following code:public class Example003 {public static void main (string[] args) {final long Micros_per_day = $ * * * + * 1000;FI nal Long MICROS_PER_DAY_L1 = 24 * * * * * * * 1000l;final Long millis_per_day = 60 * 60 * 1000;System.out.println ("NO L Print:" + micros_per_day/millis_per_day);Output 1system.out.println ("has L Print:" +micros_per_day_l1/millis_per_day); Output 2}}Output Result:NO l Print:5has L print:1000Cause Analysis:The results of output 1 and 2 are inconsistent because of t

Calculation of the hash value of chunks in Java block chainThere are many methods of calculation, such as, can be directly splicing string, can also be used StringBuffer, or StringBuilder. It uses a faster StringBuilder, and can use stringbuffer when programming.Where index is the index of block block, timestamp is the time stamp of block block, data is the block contained in the chunk, the nonce is the dif