%
%?Liscense?Notification?2013
%
%?Redistributions?in?source?and?binary?forms?with?or?without
%?modification?are?totally?FREE?provided?that?you?keep?this?keep?this
%?notification
%
%??Descritption:?This?package?demostrates?how?to?use?the?logistic
%??regression?for?classfication?of?2D?data.
%??Author:??Ranch?Lai?（ranchlai@hotmail.com）
%??Release?date:?Aug?17?2013
%/
%%
clc;
clear;
close?all;

%%
x?=?-10:0.1:10;
y?=?1./（exp（-x）+1）;
plot（xy‘g-x‘）;
title（‘logistic?function‘）;
xlabel（‘x‘）;ylabel（‘y‘）;
%%?generate?random?data
shift?=?2;
n?=?2;%2?dim
%y?=?1./exp（-w‘*x+b）
N?=?200;
x?=?[randn（nN/2）-shift?randn（nN/2）*2+shift];
y?=?[zeros（N/21）;ones（N/21）];

%show?the?data
figure;
plot（x（11:N/2）x（21:N/2）‘rs‘）;
hold?on;
plot（x（11+N/2:N）x（21+N/2:N）‘go‘）;
title（‘2d?training?data‘）;



%%
%training..
[wbcost]?=?logistic_train（xy1e-6100）;
%%
disp（‘training?ended‘）;
figure;
plot（cost‘g-s‘）;
xlabel（‘iterate‘）;
ylabel（‘cost‘）;
set（gca‘YScale‘‘log‘）;
title（‘convergence?curve‘）;


%%?plot?the?training?data
figure;
plot（x（11:N/2）x（21:N/2）‘rs‘）;
hold?on;
plot（x（1N/2+1:N）x（2N/2+1:N）‘go‘）;
%%?visualize?the?classification?aera
hold?on;
for?x?=?-shift*5:0.5:shift*5
????for?y=-shift*5:0.5:shift*5
????????if?1/（1+exp（w（1:2）‘*[x;y]+b））?>?0.5
????????????plot（xy‘g.‘）;
????????else
????????????plot（xy‘r.‘）;
????????end
????end
end
title（‘classification?result?on?training?data‘）;


%%


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