How to normalize time periods

I am very new to matlab and I don't know how to code this problem.I have two arrays: Debut and End. Each array contains doubles that indicates the start(Debut) or the end(End) of a certain period.I am doing some signal processing so I want all these periods be normalised. I am thinking of calculating the mean of all periods and then normalize each period to that mean ? or do you have any other ideas ?

Answer 1

[Aravind Ravikumar]

MATLAB has a normalize function, you can view the documentation here. From your description of your problem, you can first calculate the mean of the arrays Debut and End element-wise and then use normalize() on the resultant array. For example, the following code does somewhat similar to what you want:

x = rand(1,10);
y = rand(1,10);
avg = (x+y)/2;
norm_avg = normalize(avg);

where x,y are 2 arrays, avg is the element-wise average of x,y and norm_avg is the result after using normalize() on avg.

[Hinde essmahi BOUZIANE]

Is 'normalize' defined for input arguments of type 'double'?

[Aravind Ravikumar]

The first input argument of normalize(), ie. the object you need to normalize can have Data Types of double, single, table, timetable.

Also the input can be a vector, matrix, or a multidimensional array.

From the documentation,

N = normalize(A) returns the vectorwise z-score of the data in A with center 0 and standard deviation 1.

• If A is a vector, then normalize operates on the entire vector.
• If A is a matrix, table, or timetable, then normalize operates on each column of data separately.
• If A is a multidimensional array, then normalize operates along the first array dimension whose size does not equal 1.

Data Types: double | single | table | timetable

Complex Number Support: Yes

[Hinde essmahi BOUZIANE]

Actually I have an older version of matlab so 'normalize 'is not defined.

I tried this way:

Debut = Debut ./ max(Debut(:));

Fin = Fin ./ max(Fin(:));

But the problem is the difference somtimes is negative which was not the case before I normalized the two arrays.

[Aravind Ravikumar]

How about finding the difference between Debut, Fin first, then dividing the resultant by max(resultant). For example,

x = rand(1,10);
y = rand(1,10);
diff = y-x;
res = diff ./ max(diff)

This should not produce any negative output because before normalizing every element is positive.

[Hinde essmahi BOUZIANE]

I tought about too that but i need to use each element of the array in an other function ' arguments.

[Aravind Ravikumar]

You could keep normalized values of each array separately in some other array, and to calculate normalized value of the difference you can use the original array.

x = rand(1,10);
y = rand(1,10);
diff = y-x;

res_nor = diff ./ max(diff)
x_nor = x ./ max(x)
y_nor = y ./ max(y)

Maybe something like the above code.

Answer 2

[Akshay Malav]

Hi , there is a inbuilt function in matlab to normalize the data . Look at the link mentioned below .

The function is V = normalize(A)

V will contain the normalized value of the array A

https://www.mathworks.com/help/matlab/ref/double.normalize.html;jsessionid=40f8cb1df7d5db4996e9c83a4cce

[Hinde essmahi BOUZIANE]

s 'normalize' defined for input arguments of type 'double'?

[Akshay Malav]

Yes it is defined for double also

[Akshay Malav]

Ans also adding to above answer the normalize function ignores NaN values if it is present in your array