be able to find the global optimal solution.When the training sample is very large, each update parameter needs to traverse all the sample calculation total error, so that the learning speed is too slow; this time the random gradient descent algorithm that calculates the error update parameters of a sample is usually more thanThe batch gradient descent method is faster. (Theoretically, there is no guarantee that the random gradient descent can converge)4. For the least squares of linear regress
training set is appropriate.3. No supervised learningExample: In the case of the tumour above, the point in the figure does not know the correct answer, but is from you to find a certain structure, that is, clustering .Applied in the fields of biological genetic engineering, image processing, computer vision, etc.Example: Cocktail party issuesPick up the sounds you're interested in during a noisy cocktail partyUse two different positions to separate the sound from different positionscan also be
Addgesturerecognizer:[[uipinchgesturerecognizer alloc] InitWithTarget:self.faceView action:@ Selector (pinch:)]; //the target here is the handler for this gesture, the Self.faceview .[Self.faceview Addgesturerecognizer:[[uipangesturerecognizer alloc]initwithtarget:self Action: @selector ( Handlehappinessgesture:)]; Self.faceView.dataSource=self;//the controller sets itself as the delegate} //adding gesture recognition to Faceview,faceview will handle gestures through pinch. -(void)
. Summarize the above experimental results:4. The following should be the principle of Li Feifei's Ted speech:5. Some recommendations for working with small datasets:V: Squeezing out of the last few Percent1. Using a small size filter is much better than using a large size filter, and a small size filter can increase the number of non-linearities and reduce the parameters that need to be trained (imagine a 7*7 patch with a 7 The filter convolution of the *7, and the filter convolution of the thr
be trained and predicted immediately, which is called Online learning. each of the previously learned models can do online learning, but given the real-time nature, not every model can be updated in a short time and the next prediction, and the perceptron algorithm is well suited to do online learning:The parameter Update method is: if hθ (x) = y is accurate, the parameter is not updated otherwise, θ:=θ+ yx (in fact, this formula and gradient descent update strategy is the same, but the class l
Machine learning defines learning definitionArthur Samuel (1959). Machine Learning:field of study, gives computers the ability to learn without being explicitly programmed.There is no clear programming case to make the computer capable of learning the field of study.Four parts:The first part:Supervised Learning supervised learningPart II:Learning theoryPart IV:Unsupervised learningUnsupervised learningClustering algorithmComputer cluster organization, social network analysis, market divisionICA
is that only the input paradigm is provided for this network, and it automatically identifies its potential class rules from those examples. When the study is complete and tested, it can also be applied to new cases.
A typical example of unsupervised learning is clustering. The purpose of clustering is to bring together things that are similar, and we do not care what this class is. Therefore, a clustering algorithm usually needs to know how to calculate the similarity to begin to work.
distribution with the mean value of μ 0 and the covariance matrix of Σ, X | y = 1 follows the multivariate Gaussian distribution where the mean value is μ1 and the covariance matrix is Σ (This will be discussed later ).
The log function for maximum likelihood estimation is recorded as L (ø, μ 0, μ 1, Σ) = Log 1_mi = 1 p (x (I) | Y (I); μ 0, μ 1, Σ) P (Y (I); ø), our goal is to obtain the parameter ø, μ 0, μ 1, Σ to make L (ø, μ 0, 1, Σ) to obtain the maximum value.
The values of the four para
Stanford ml Open Course Notes 15In the previous note, we talked about PCA ). PCA is a direct dimensionality reduction method. It solves feature values and feature vectors and selects feature vectors with larger feature values to achieve dimensionality reduction.This article continues with the topic of PCA, including one application of PCA-LSI (Latent Semantic Indexing, implicit semantic index) and one implementation of PCA-SVD (Singular Value Decompos
hyper-plane (w,b) and the entire training set is defined as:Similar to the function interval, take the smallest geometric interval in the sample.The maximum interval classifier can be regarded as the predecessor of the support vector machine, and is a learning algorithm, which chooses the specific W and b to maximize the geometrical interval. The maximum classification interval is an optimization problem such as the following:That is, the selection of γ,w,b is the maximum gamma, while satisfyin
to return to the previous page. So how to get our action sheet on the screen, using method Presentviewcontroller, the whole method is to make a controller the current controller:Completion is a closure that is called when the Actionsheet renders to the page.The ipad is presented in a popover way.The use of alert is similarWe want to add a text box to the alert by doing the following:Once this method is called, the text box set in the closure will work, where a placeholder is set for the text bo
exposed to nsnotification before, as shown in the example above, receiving this nsnotification in the message center, The nsnotification is then captured in the method thekeyboardappeared of the selector and then extracted from the information in the UserInfo for related processing.Here are some of the other properties of Uitextfield, very interestingFor example, you can set the font size to fit the width of the text box when the text input is many, but the font cannot be reduced indefinitely,
We have a info.plist file in our project, we have been in touch with this file since we did the localization setup, there are many settings.You can even view it in XML format, but usually you edit this file by clicking on the project name at the top of the engineering catalog:You have a lot of features in your app that you can't use until you set them up to enable, and the switch is interesting to indicate whether it's available via a switch, such as when we used the Mapkit to do the map functio
Judgment statement if imageData! = nil{ self.image = UIImage (data:imagedata!) } else { self . Image = Nil}}}}} Note that when calling spinner it is optional, because the page may be generated before the spinner control, which is a common approach when invoking the control. However, this method is loaded with different processing situations, in common with the image, so we choose to stop the gears in the set method that calculates the attribute image:Private var i
, the white split line means that it can be accessed directly, and the yellow split line means that it cannot be accessed directly.We now want to access the properties in a view uiview, we need to use outlet for direct access, if there are certain events in the view (such as click, Swipe) to notify the controller (controllers) need to be accessed by action or delegate way, The model data changes are broadcast to notify the controller.Third, the first objective-c focus and points of attentionWe c
Recently started to learn Swift to develop mobile programs. Follow Stanford's Open class for self-study.This is a wonderful time, although not at Stanford School, but can watch the recorded video, lectures, as if the teacher is giving us a lesson!Experience:1, each lesson information is very large, each word, each operation is intentional and for it. Need to have a good experience after class, according to the knowledge points in the class to practice
image? We have a uiimageview that shows pictures, but you may want to throw your pictures into the drawrect.In general you will create a picture with a name in order to get it out of the images.xcassets.Once you have this picture, you can send a message to show it, this method is Drawatpoint, then the system will put the normal size of the picture in the upper left corner of the point.You can also use the Drawinrect method, which will scale the image in this rectangular area.Or, as we said befo
{ faceview.datasource = self } }The other thing to do is to let Faceview redraw itself every time our model changes. We need to complete UpdateUI this method:Func UpdateUI () { faceview.setneedsdisplay () }The meaning here is to call my drawrect function and redraw me. If you do not do this step then modify the value of the happiness the face of the little man will not change. Let's change the value of happiness to 75 to run a look at the effect:A very cute smiley face. "W
two constraints, a horizontal center, and a bottom distance:We create a third button in the same way:Let's Run our program:You can see that the top text is cut off and rotated:It looks good in the horizontal screen mode, but the vertical screen is not going to work. Since we have set the font size to 36th, you can see it in the autoshrink of the storyboard property monitor, the current setting is fixedFont size (fixed font size):But this font does not need a fixed size, I need to set its minimu
Stanford iOS Learn Notes, stanfordios
During this time, I was studying Stanford's iOS 8 teaching video, so I was not thinking about it, so I was prepared to summarize some notes about the video learning so that I could understand it more easily.
Now I have learned six lessons. From these six lessons, the first three lessons mainly focus on a Demo of Calculator and interspersed with a few iOS introductions, and MVC introduction. Section 4 mainly intr
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