How to check whether point is changed or not in MatLab? - ischange -- MatLab

How to check whether point is changed or not in MatLab?

[Ans]

ischange

NOT ischanged

[Syntax]

<TF> = ischange(<A>)

<TF> = ischange(A,<method>)

<TF> = ischange(___,<dim>)

<TF> = ischange(___,<Name>,<Value>)

[<TF>,<S1>] = ischange(___)

[TF,S1,S2] = ischange(___)

[Description]

Find abrupt points in data.

i.e. find the points which is changed by your definition or by default.

By default, <method> is set to mean.

e.g.

 TF = ischange(A) 

It will return true when there is an abrupt change in mean of corresponding element of A.

Otherwise, return false.

 TF = ischange(A,'variance') 

It will return true when there is an abrupt change in variance of corresponding element of A.

Otherwise, return false.

(1)

[<TF>,<S1>,<S2>]=ischange(__)

It will return 3 variable.

<TF> 

check an abrupted change by default or your definition. I mentioned it above.

vector type.

<S1>

S1 contains the mean for each segment.

vector type.

<S2>

S2 contains the variance for each segment.

vector type.

(2)

<TF>=ischange(<A>,<methodName>)

It will specify your definition through your methodName.

The syntax is same as others. 

(3)

<TF>=ischange(__,<dim>)

The syntax is same as others

But it will specify the dimension of A through <dim>.

(4)I really can't understand it.

<TF>=ischange(__,<Name>,<Value>)

The syntax is same as others.

But it will specify the <Name> as  <Value>.

I think it's wrong.

e.g.

[TF,S1,S2] = ischange(A,'linear','Threshold',200);

It will specify a linear point which Threshold is Greater Than 200 is an abrupted point.

code

clear

clc

A = [zeros(1,100) 1:100 99:-1:50 50*ones(1,250)] + 10*rand(1,500);

[TF,S1,S2] = ischange(A,'linear','Threshold',200)

segline =

S1.*(1:500) + S2;

plot(1:500,A,1:500,segline);

%legend('Data','Linear Regime');

                        fig(a)

more details on:

Find abrupt changes in data - MATLAB ischange (mathworks.com)