maximum values in vector

hi everyone, i have a vector consist of 5000 elements and i need to find the maximum values for 2000 elements with their real index , plz can anyone help me in that? thx

Answer 1

[Star Strider]

The max function will return only the first maximum in the array if there are more than one. To find all of them, use find:

Example:

Vector = randi(5, 1, 15)
MaxValuesIdx = find(Vector == max(Vector))

produces (in this instance):

Vector =

       3     1     2     5     1     3     5     3     4     5     5     2     4     2     1

MaxValuesIdx =

       4     7    10    11

EDIT — To get the highest 2000 values, use the sort function.

Answer 2

[Image Analyst]

Which 2000? The first 2000? Try this

[maxValue, indexOfMaxValue] = max(yourVector(1:2000));

What does "without changing positions mean"? Do you want an array of the same length but all zeros except for the max being in its original location? If so

output = zeros(size(yourVector)); % Initialize
yourVector(indexOfMaxValue) = maxValue; % Assign that one element

[RAAD AL-DULAIMI]

thanx for responding ,,, i mean that i need the highest 2000 values on these 5000 . and the real index of those 2000 in the vector