Trend analysis

Hello everyone here is my problem

function trend

Data=xlsread('datatrend.xlsx');

D=Data(:,1);

for i=1:10;

      t=D(i,1);
      for j=(i+1):10;
          x=t-D(j,1);
          y=sign(x);

      end

end

end

The thing I am trying to do is this:

I need to write a code that will do some calculation on a matrix that has 1 column and more than 10 rows ( row number can change ). I divide the calculations in to the steps;

a. Firstly it should take first row and substract second row from it so "R1-R2" basically

b. If the outcome of the substraction is positive it should take variable as 1, if the outcome is negative it should take variable as -1 and if the outcome is 0 it should take variable as 0

c. The program need to do above for "R1-R3", "R1-R4" so in short it should substract each row from "Row1" and determine what the variable will be

d. After this step is done for "Row1" it should now do it for "Row2" which includes same as step "c" and substract all rows from "Row2" except it shouldn't substract any row above "Row2" from it. For example like "R2-R3" , "R2-R4" and so on.

e. Same steps for "Row3". "R3-R4", "R3-R5" ....

f. So overall it should do these substractions and sum up all the 1,0,-1 that has been recorded from it and give me a summation

I'd much appreciate if anyone can help me on this I got the basic idea of how to write it but can not get any result out of it:S

Answer 1

[Daniel Shub]

I haven't read your whole question, but the code looks a little suspicious to me. Are you sure you do not want

y(i,j)=sign(x);

currently your code just keeps writing over y.

Answer 2

[hasan]

Well what I am trying to achieve is to get signum value of the outcomes as it can be +1 if positive , -1 if negative and 0 if it is 0.

I am trying to sum up all the outputs from signum please read the full question I explained it better on there I just don't know how to write this code.