coursera scala

1.If statementsScala's If statement can complete the IF statement in other languages, at the same time, if/else usually has values that can be used to assign values, or instead of the ternary conditional operator (?:). However, it can be more powerful than the conditional operator because you can write very complex blocks in If-else.1.1. Common IF statements package com.tv189.foundation Span style= "color: #008000;" >/** * Created by Molyeo on 2015/7/30. */ object ifcondition {def main (ar

Install Scala and Scala IDE in Ubuntu 16.04 and Windows1. Download 1.1Scala Http://www.scala-lang.org/download/ for Windows Http://www.scala-lang.org/download/2.11.8.html (Linux) Below: Download 1.2ScalaIDE : Http://scala-ide.org/download/sdk.html 2. Install Scala in Windows Environment: Windows10 + JDK1.7 + Scala2.11

Welcome to visit This journey contains a few streamlined introductions: the most common features of Scala are presented. It is designed to help beginners learn the language. This is just a brief introduction, not a complete language tutorial. If you can, consider buying a book or reviewing other resources. What is Scala? Scala is a modern, multi-paradigm programm

[TOC] Array fixed-length arraysIf you need an array of the same length, you can use the arrays in Scala. For example:val numsArray = new Array[Int] (30) //长度为30的整数数组，所有元素初始化为0val stringArrays = new Array [String] (30) //长度为30的字符串数组，所有元素初始化为nullval sHello = Array("Hello", "World") //长度为2的Array[String]类型是推断出来的，已提供初始值就不需要newsHello(0) = "Hello Tom",使用()而不是[]来访问元素In the JVM, Scala's array is implemented as a Java array. The array in the example is of

Scala Development Environment BuildingLet's start with some of the reasons why I study Scala: The JVM's dominance in the enterprise, Scala is also the language on the JVM, and it is likely that the future will be too much from Java to Scala. Advanced functional programming and object-oriented integration.

would the Vectorize this code to run without all for loops? Check all the Apply. A: v = A * x; B: v = Ax; C: V =x ' * A; D: v = SUM (A * x); Answer: A. v = a * x; v = ax:undefined function or variable ' Ax '. 4.Say you has a vectors v and Wwith 7 elements (i.e., they has dimensions 7x1). Consider the following code: z = 0; For i = 1:7 Z = z + V (i) * W (i) End Which of the following vectorizations correctly compute Z? Check all the Apply.

(w ')Description W over fitting3 Sources of errorNoise, Bias, Variance1. Noise NoiseOf an inherent, irreducible, or reduced nature.　　　2, Bias Deviation　　　　　　The simpler the model, the greater the deviation　　The more complex the model, the smaller the deviation3. Variance Variance　　　　Simple model, small variance　　Complex model, large variance　　Deviations and variance tradeoffs, deviations and variances cannot be calculated　　　　Training error and the amount of test data, fixed model complexity, a

-Normal equationSo far, the gradient descent algorithm has been used in linear regression problems, but for some linear regression problems, the normal equation method is a better solution.The normal equation is solved by solving the following equations to find the parameters that make the cost function least:Assuming our training set feature matrix is x, our training set results are vector y, then the normal equation is used to solve the vector:The following table shows the data as an example:T

Week 4 Quizhelp Center Warning:the hard deadline has passed. You can attempt it, Butyou won't get credit for it. You are are welcome to try it as a learning exercise. In accordance with the Coursera Honor Code, I certify This answers here are I own work. Question 1 Which of the following is nottrue about GFS? The GFS keeps multiple replicas of the same file chunk. The file data transfer happens directly between the GFS client and the GFS chunkservers

Week 2 Quizhelp Center Warning:the hard deadline has passed. You can attempt it, but and you won't be. You are are welcome to try it as a learning exercise. In accordance with the Coursera Honor Code, I certify this answers here are I own work. Question 1 Suppose a query has a total of 4 relevant documents in the collection. System A and System B have each retrieved, and the relevance status of the ranked lists is shown below: System A: [-----------]

SCALA Study Notes (1), SCALA Study Notes (Variable When obtaining the variable value is time-consuming, you can use lazy var.Lazy val forLater = someTimeConsumingOperation () Scala> val first: rest = List (1, 2, 3)First: Int = 1Rest: List [Int] = List (2, 3)Function Definition "=" Is not just used to separate the function signature and function body. It also ser

In the previous article we described how to install Scala and how to configure environment variables Next we'll explain how to use the interpreter to write simple Scala code Open the console and enter Scala development mode: bokee@debian70:~$ Scala Welcome to Scala version

(Paddle2_pos,1,'Blue',' White') #determine whether paddle and ball collide ifBall_pos[0] Pad_width:ifBALL_POS[1] >= paddle1_pos[0][1] andBALL_POS[1] ]: Spawn_ball (right)Else: Score2+ = 1ifBall_pos[0] >= Width-pad_width-Ball_radius:ifBALL_POS[1] >= paddle2_pos[0][1] andBALL_POS[1] ]: Spawn_ball (left)Else: Score1+ = 1#Draw scoresCanvas.draw_text (str (score1), [WIDTH/2-40, 40], 30,' White') Canvas.draw_text (str (score2), [WIDTH/2 + 20, 40], 30,' White')defKeyDown (key):GlobalPaddle1_vel,

(stop_num)#define event handlers for buttons; "Start", "Stop", "Reset"defStart_handler (): Timer.start ()defStop_handler (): Timer.stop ()defReset_handler (): Timer.stop ()GlobalTGlobalt_str Reset_score ()#Define event handler for timer with 0.1 sec intervaldefTimer_handler ():GlobalTGlobalT_str T= t + 1T_str=format (t)defTimer_score_handler (): Update_score ()#Define Draw HandlerdefDraw_handler (Canvas): Canvas.draw_text (t_str, Position,36," White") Canvas.draw_text (SCORE_STR, [160, 20], 16,

#include using namespacestd;/*int Wanmeifugai (int n) {if (n%2) {return 0; } else if (n==2) {return 3; }else if (n = = 0) return 1; else return (3*3) *wanmeifugai (n-4);}*///The following is a reference to the online program/*Ideas: Citation:http://m.blog.csdn.net/blog/njukingway/20451825First: F (n) = 3*f (n-2) + ... f (n) = 3*f (n-2) + 2*f (n-4) +....//just now our recursion is pushed in the smallest unit (3 blocks), but there are large units of small units (6, 9, 12 blocks, etc.) There

y += 1 timer.stop() elif timer.is_running(): y += 1 timer.stop() def reset(): global t, x, y t = 0 x = 0 y = 0 timer.stop()# define event handler for timer with 0.1 sec intervaldef tick(): global t t += 1#不需要return# define draw handlerdef draw(canvas): canvas.draw_text(format(t), [80, 120], 50, "White") canvas.draw_text(str(x) + "/" + str(y), [220, 30], 35, "Green")# create framef = simplegui.create_frame("Stopwatch", 300, 200)

Week 2 gradient descent for multiple variables [1] multi-variable linear model cost function Answer: AB [2] feature scaling feature Scaling Answer: d 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: 【] Answer: [Original] Andrew Ng chose to fill in the blanks in Coursera for Stanford machine learning.

m>=10n and uses multiple Gaussian distributions.In practical applications, the original model is more commonly used, the average person will manually add additional variables.If the σ matrix is found to be irreversible in practical applications, there are 2 possible reasons for this:1. The condition of M greater than N is not satisfied.2. There are redundant variables (at least 2 variables are exactly the same, XI=XJ,XK=XI+XJ). is actually caused by the linear correlation of the characteristic

different lambda, the calculated training error and cross-validation error are as follows:Lambda Train error Validation error 0.000000 0.173616 22.066602 0.001000 0.156653 18.597638 0.003000 0.190298 19.981503 0.010000 0.221975 16.969087 0.030000 0.281852 12.829003 0.100000 0.459318 7.587013 0.300000 0.921760 1.000000 2.076188 4.260625 3.000000 4.901351 3.822907 10.000000 16.092213 9.945508The graphic is represented as follows:As

, the weight of the high-weighted data is increased by 1000 times times the probability, which is equivalent to replication. However, if you are traversing the entire test set (not sampling) to calculate the error, there is no need to modify the call probability, just add the weights of the corresponding errors and divide by N. So far, we have expanded the VC Bound, which is also set up on the issue of multiple classifications!SummaryFor more discussion and exchange on machine learning, please