http://sbp810050504.blog.51cto.com/2799422/1608064/

http://blog.csdn.net/dongtingzhizi/article/details/15962797

http://blog.csdn.net/llp1992/article/details/45114421

https://www.qcloud.com/community/article/180954?fromSource=gwzcw.107192.107192.107192

梯度上升法求函數極值

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來源: 運籌學第3版 胡運權 第3 節無約束極值問題的解法

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logistic回歸進行二分類

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function weight = gradAscent clc % close all clear %%data = load('testSet.txt'); [row , col] = size(data); dataMat = data(:,1:col-1); dataMat = [ones(row,1) dataMat] ; labelMat = data(:,col); alpha = 0.001; maxCycle = 500; weight = ones(col,1); for i = 1:maxCycleh = sigmoid(dataMat * weight);error = (labelMat - h);weight = weight + alpha * dataMat' * error; endfigure scatter(dataMat(find(labelMat(:) == 0),2),dataMat(find(labelMat(:) == 0),3),3); hold on scatter(dataMat(find(labelMat(:) == 1),2),dataMat(find(labelMat(:) == 1),3),5); hold on x = -3:0.1:3; y = (-weight(1)-weight(2)*x)/weight(3); plot(x,y) hold offendfunction returnVals = sigmoid(inX)returnVals = 1.0./(1.0+exp(-inX)); end

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轉載于:https://www.cnblogs.com/adong7639/p/7181369.html

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