Comparing elements in one matrix in a loop

Hi All,

I have a large matrix with one column containing only values. I want to make a loop and compare every time if the average of 2nd and 1st value is < than a predifined value. When the average of i and j value is > than the predifined value, to show as a result i and j. Thanks in advance!

Answer 1

[KALYAN ACHARJYA]

A=randi(30,20,1); %Random Matrix for Example
th=12; %Some Predefined value
[rows colm]=size(A);
for i=1:rows-1
     c=(A(i,1)+A(i+1,1))/2;
if c > th
     fprintf('The i is: %d and the next row i+1 value is: %d \n',i,i+1);
     break;
end 
end

[KALYAN ACHARJYA]

The matrix you said having 1 column, so j value always 1.

[Ancalagon8]

thanks for your answer. The matrix does have 1 collumn but i and j i want to be the values position for example i(cell 502) and j the next one (cell 503)

[KALYAN ACHARJYA]

What are i and j, as you are assuming?

Look at here for cell array

[Ancalagon8]

the position where c > th. For example if my matrix has length 10000, i=9000, j=9001 (the next one).Position not value

[KALYAN ACHARJYA]

Next position is i+1, why j?

Array having length, matrix has size, confirm?

Check my answer, it works as per your defined question (matrix case).

Anyway I am ready to help if I can

[Ancalagon8]

i have a matrix 2000000x1 double.

i get the following error: "error in mean dimension argument must be a positive integer scalar with indexing range"

[KALYAN ACHARJYA]

In My Example A is 20x1 Double, check the following-

[Ancalagon8]

I want to find in which position of my matrix (i and j or 500 and 501 or 9000 and 9001) c > th. i want to compare every two elements the average of the two with the th value until this average (c) gets a value larger than th.

[KALYAN ACHARJYA]

Check I have edited the answer. You want to find all positions or the first one only? Like the following?

[Ancalagon8]

The first one only. It is ok now! is there any possibility ( as a second way) to check instead of c>th, if c gets 3 digits from 2? for example c=50,c= 80, c=105 then fprint.

Thanks in advance!

[KALYAN ACHARJYA]

The first one only case. I have edited the answer, the added break statement. Please check.

Other c condition also possible, can you clarify more.

[Ancalagon8]

for example doing inside the loop the calculation to find c gives a 2-digit-result like

(11+10)/2= 10.5, ....... ,

....., (46+38)/2=42,

(468+46)/2=257 <-- so here break as the result has 3 digits