Finding t that a max/min occurs at

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I have a f(t) = [600x1] matrix and I need to find the t where the max and the min occur. I know how to find the max and min, but I am not sure how to then find what t these occured at. So if my max is 70, I need to find the t value that gives f(t) = 70. What is the best way to find t? Thanks!

回答(2 个)

Image Analyst
Image Analyst 2018-12-1
You need to use BOTH min(), max() AND find() to get ALL of the locations:
ft = randi(70, 600, 1); % Sample data
% Step 1: find the max and min values.
maxValue = max(ft)
minValue = min(ft)
% Step 2, find out what rows they occur at.
% NOTE: cannot use the second return value of max() and min() for this
% because it will return ONLY the first occurrence
% of the max or min, not ALL of them
indexesOfMax = find(ft == maxValue)
indexesOfMin = find(ft == minValue)
  2 个评论
Shawna Myatt
Shawna Myatt 2018-12-2
Thank you! between the value code that was given earlier and the find command, I was able to figure it out.
Image Analyst
Image Analyst 2018-12-2
"Figure it out"? What was left to figure out?
This gave you very explicitly the answer of what indexes the maximum occurred at. Other than possibly renaming my variables, what changes needed to be made?

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madhan ravi
madhan ravi 2018-12-1
[value,index]=max(f)
t(index)
[value,index]=min(f)
t(index)
  3 个评论
madhan ravi
madhan ravi 2018-12-1
v(t==100) % to find v when t is 100
value=max(v(t>=1 & t<=10))
value1=min(v(t>=10 & t<=20))
value2=max(v(t>=40 & t<=50))
Shawna Myatt
Shawna Myatt 2018-12-2
Thanks! Between this and the find command, I was able to figure it out.

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