calculated as the predictive accuracy.①: Rating prediction: General mean-square error (RMSE) and mean absolute error (MAE) calculationRMSE:
Recommended system->USERCF Algorithm _ Recommendation System ">
MAE:Recommended system->USERCF Algorithm _ Recommendation System ">
Import Math
def RMSE (Records): Re
The shell can often be seen: >/dev/null 2>1Eg:sudo kill-9 ' ps-elf |grep-v grep|grep $1|awk ' {print $4} ' 1>/dev/null 2>/dev/nullThe result of the command can be defined in the form of a%> output/dev/null represents an empty device fileWhere does the &
distance. However, in the case of a very high number of cycles, the loop instruction is more efficient because the branch prediction success rate for the loop instruction is 100% (the value of the cx/ecx before the loop instruction executes is known). So we try to use CMP to set loops
the real mode of memory layout below real mode is to be compatible with 8086, so only 20 address lines are supported and 20 =1mb:0x00000--0xfffff of 2. The following figure is 1M of memory layout: 0--0X9FFFF is dr
Preface
This article is based on the translation of the first chapter of Autotools-a Practioner's Guide to GNU Autoconf, Automake, and Libtool, omitting some of the statements.
Body
As the preface says, the GNU Autotools is designed to make life easier for end users, not defenders. Even so, in the long run, using Autotools as a project manager will make your job easier, though it may not be the reason you suspect it. The Autotools framework is as simple as possible, giving the functionality i
File transfer between different systems *******# # 1 # # File archiveFile archiving is to turn multiple files into an archive fileSetting method: Tar parameterc//creation, createF//Specify file Archive file namet//Show archived file contents, ListR//Add a file to the specified archive file, append--get//Remove a single file--delete//delete individual filesX//Remove all content from the archive. Extract|ge-c//Specify the directory of files, directory-Z//gz format compression, gzip-J//bz format co
This paper analyzes the usage of $this->load->library () in CI framework. Share to everyone for your reference, specific as follows:
The first time I failed to load, originally is the file name and class name for different reasons, first summed up about CI loading your own class file considerations:
1. Third party loaded items should be placed under Application/libraries documents
2. FileName and c
In the process of learning Linux, often see some terminal commands or programs have ">/dev/null 2>1" appear, because have met several times, in order to understand clearly, may wish to spend some time Baidu or Google related knowledge.0: Indicates keyboard input (stdin)1: Indicates standard output (stdout), system default is 12: Indicates error output (stderr)Command &
int i = 16; System.out.println (I>>2);The result is 4.int i = 16; System.out.println (I>>32);The result is 16.Usually we understand m>>n as the current value m divided by 2 N, and the same because the argument to
One, error C1189: #error: WINDOWS. H already included. MFC apps must not #include
This error is often reported when we introduce MFC into the Win32 application that we built in vs2013. This is because WINDOWS.H has been introduced into MFC's class library files,
In VS, each. App file introduces the stdafx.h header file by default, and the following code is the entire contents of stdafx.h, which is also introduced into the WINDOWS.H
#include "Targetver.h"#define Win32_lean_and_mean#include #inc
Prepare the database (MySQL), if you already have MySQL, can be ignored.Build MySQL table;Connect to MySQL;Mysql-u root-pCreate a data table;Mysql> CREATE DATABASE demo;Mysql> use demo;Mysql> CREATE TABLE Pet (name varchar (), owner varchar (+), species varchar (+), sex char (1));Add data table contents;Mysql>
Program flow control Statements in Java include conditional structure, loop structure, and jump statements4.1-Piece structureThe conditional structure includes the sequential structure and the selection structure. The sequential structure does not jump and judge in program execution until the program is finished. The selection structure includes the IF statement, the If-else statement, and the switch statement, which can change the execution process of the program during program execution.4.1.1
In today's succession review, I have a new insight into the attributes of inheritance------> Subclass inherits the parent class, inherits the parent class's methods and properties, and looks at the following figure
Inheritance---> Properties (two ways to call the parent class with the same name in a subclass) ">
As you can see from the diagram above,
$this->db->update_batch ();Generating an update command is based on the data you provide and executes the query. You can pass an array or an object's arguments to the Update_batch () function. The following is an example of using an array as a parameter: generates an update string based on the data supply, and runs the query. You can either pass a array or an object to the function. A example using an
Unit Seventh ***************# # 1 # # Process definitionProcess is the work that the CPU does not complete# # 2 # # PS commandPsAll processes running in a//shellX//All processes not in Shell re-runU//View process user InformationL//Show process detailsF//Full information abbreviationE//Show all processes in the current user shellPS Ax-o%cpu,%mem,user,group,comm,nice,pid//Specify some information for the display process%CPU//Show process CPU load%men//Show process memory loadUser//Process usersGr
Hi ! Recently learned a new skill, learning the knowledge of the database, here to give you a talk, hope enlighten!! >>01. First, let's talk about why we use the database.a database can be viewed as a repository for permanent data storage. can store large amounts of dataData consistency and integrity can be guaranteedTo meet the sharing and security requirements of your appConvenient and intelligent
Mybatis Mapper中文件中When you update, you need set to set multiple fields, sometimes the comma processing, will report an error, so will use to Trim is used to remove the "," of the last field.It is not necessary to write the set individually because set is included in Trim:UpdateID= "Update"ParameterType= "Com.entity.Entity"> Trimprefix= "Set"Suffixoverrides=","> ifTest= "Ispublish!=nu
When doing network service, it is necessary to write concurrent service-side programs. The stability of the front-end client application is partly dependent on the client itself, and more depends on whether the server is fast enough and stable enough.The common Linux concurrent Server model;
Multi-Process Concurrent server
Multi-threaded Concurrent server
Select multi-channel I/O transfer server
Poll Multi-channel I/O forwarding server
Epool Multi-Channel I/O forwarding server.
This
"Preface" Self start with a link four pseudo-class start, I only remember that is so stipulated, recently in the study of CSS Foundation, found that the real reason for writing order is because ... Start by understanding a few concepts.
degree of specificity: it is used to measure the priority of a selector. Like what:
Div-->1
. ab-->10
#nav-->100
Div. a
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