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different linear regression algorithm is Formed. The linear regression algorithm library in Scikit-learn can find their differences from these three points. Understanding these different points, the use of different algorithms to understand the scene is Good.1. linearregression Loss Function:The Linearregression cl
the green point. So, when I go one step further down the gradient, my derivative term is smaller, and the amplitude of the θ1 update will be smaller. So as the gradient descent method runs, the amplitude of your move will automatically become smaller until the final movement amplitude is very small, and you will find that it has converged to local minima. Lookin
, isn't it?But you can't just watch the buzz and analyze-why is that?The first-order requirements that are satisfied by the exact line search are: , i.e.Therefore, by the steepest descent method :That is: The search direction of the next two times is straight to each other (projected on the two-dimensional plane, is the sawtooth shape).Article Source: http://www.codelast.com/If you have to ask, why is it that the two vectors are directly interacting w
). The advantage of this approach is that the calculation is simple, but requires the data matrix X full rank, and when the data dimension is high, the calculation is very slow, we should consider using gradient descent method or random gradient descent (the same as the idea of logistic
Ufldl Study Notes and programming assignments: Linear Regression (linear regression)
Ufldl provides a new tutorial, which is better than the previous one. Starting from the basics, the system is clear and has programming practices. In the high-quality deep learning group, you can learn DL directly without having to de
the Theta calculated with the trained amount .In This paper, we use the method of gradient descent to realize the regularization of linear Regression by using Python .summarize some important places,1 I do not preprocess the data here, because each feature is worth the order of magnitude to keep. There are two ways to
column of ones to Xtheta = zeros (Size (x (1,:))) ';% Initialize fitting parametersmax_itr = 1500;alpha = 0.07;for nu M_iterations = 1:max_itr% This is a vectorized version of the gradient descent update formula% It ' s also fin E to using the summation formula from the videos the derivative of the cost function of the gradient%: it is just the case that the j=
. There are a certain number of samples in our training set. We know which house X indicates to sell and the actual price of the house. Therefore, we need to select the parameter value, make sure that the X value provided in the training set can accurately predict the value of Y.
Let's give a standard definition,In linear regression, what we need to solve is a minimal problem..
The selected parameters
In the application of machine learning algorithms, we usually use the gradient descent method to train the algorithm used. In fact, the commonly used gradient descent method also contains three different forms, and they each have different advantages and disadvantages.In the following, we compare three
Linear regression is the most typical regression problem, and its target value has a linear relationship with all the features . Linear regression is similar to logistic regression, whe
://www.zhizhihu.com/html/y2011/3632.htmlHttp://www.th7.cn/system/win/201511/142910.shtml======================================================= the following link to see first http://www.cnblogs.com/python27/p/MachineLearningWeek10.html gradient descent (BGD), random gradient descent (SGD), Mini-batch
0.01
2.0013
4
0.03
0.00
2.0002
5
0.01
0.00
2.0000
6
0.00
0.00
2.0000
Conclusion: It can be found that the algorithm converges after the 6th iteration. The minimum value to be calculated is 2.How does the gradient descent algorithm make convergence judgment? A common method is to determine whether the a
the solution methods, and the Gaussian-Newton method and the Levenberg-marquardt can be used to solve the nonlinear least squares in solving the linear least squares.For details, refer to Wikipedia (Least squares, Gradient descent, Gauss-newton algorithm, Levenberg-marquardt algorithm)The gradient
little bit at a time, and when does it get to the bottom? What happens when J (θ1) crosses the minimum to the other side if the stride is too large? These two problems have a great relationship with the learning rate α . If α is too small, the gradient descent algorithm will be quite slow. If α is too large, the gradient drop may cross the minimum, leading to no
direction, after several iterations to findLocal Minimum。 The disadvantage of gradient descent method is that the convergence speed slows down to the minimum point, and the selection of the initial point is very sensitive, and the improvement is mostly in these two aspects.edited on 2013-03-21 1 Reviewsendorsement 3 objection, will not show your nameUser-aware,I've been doing nothing latelySpirit_dongd
Use tensorflow to implement linear regression of data
Import related libraries
import tensorflow as tfimport numpyimport matplotlib.pyplot as pltrng = numpy.random
Parameter settings
learning_rate = 0.01training_epochs = 1000display_step = 50
Training data
train_X = numpy.asarray([3.3,4.4,5.5,6.71,6.93,4.168,9.779,6.182,7.59,2.167, 7.042,10.791,5.313,7.997,5.654,9.27,3.1])train_Y = numpy
regression and gradient descent:
Regression in mathematics is given a set of points, can be used to fit a curve, if the curve is a straight line, that is called linear regression, if the curve is a two-time curve, is called two
/2m ... hθ (x) =θ0 +θ1*x When we need to determine the derivative of each parameter:
When j = 0 when j = 1 identifies the partial derivative of the needle for θ0 and θ1
When we derivative this expression according to J = 0 and J = 1, we get the following results
To check this, you need to know multivariate calculus
So we can reinsert these values into the gradient descent algorithm and how it works.
It is a
1. Linear regression (linear regression):
B, multivariate linear regressionMultivariate linear regression:
The form is as follows:
The order is therefore: there are parameters: Then,
First, what is gradient descent method
Gradient Descent method Gradient descent
1. Not a machine learning algorithm
2. is a search-based optimization method
3. Function: Minimize a loss function
4.
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