Find the minimum distance to a number from the elements of an array in MATLAB

Question

What is an efficient way to find the smallest distance from a number lets say 2.5 in an array A in MATLAB?

The problem I have is that while I use the function min

     min(abs(A - 2.5))

I get an answer e.g 0.0053 I do not know what is the index of the number that gives the smallest difference after the subtraction.

I tried to add again the number so I get 2.5053 and when I try to do

     find(2.5053)

I get:

     Empty matrix: 1-by-0

for your find command, you'd want to use `find(A==2.5+minimum)`, where `minimum` is the result of the `min` operation — Jonas, Dec 03 '13 at 15:49
@Jonas But because of `abs`, it might have to be with a minus sign, instead of a plus sign — Luis Mendo, Dec 03 '13 at 16:20

score 6 · Accepted Answer · edited May 23 '17 at 12:19

6

Just use the second output of min:

[value, index] = min(abs(A - 2.5));

Adding the number and then using find has several problems:

It's less efficient.
How do you know if you have to add or subtract? You are using abs.
Comparing doubles for equality is not usually a good idea, because of finite precision.

edited May 23 '17 at 12:19

Community

answered Dec 03 '13 at 15:32

Luis Mendo

1 Answers1