Approximately equal or egual to +- error

Hi,

I have two vectors where each has a column with approximately equal values like this:

Vector1 Vector2

1.11111 1.2222

1.12111 1.2238

... ...

1.2223 1.4446

Since the value of Vector1: 1.2223 is not exactly equal to the value of Vector2: 1.2222 I cannot use the equal to command to find the value 1.2223 in vector2.

What I'm looking for is a command or a way to find a value in vector2 that is approximately equal to a value from vector1 within some limits.

It could look like this:

find(vector2(:,1))=vector1(1,?)+-0.0001

Where +-0.0001 would be the limits. But you can't write it like this.

I'm thankful for any hint.

Answer 1

[Andrei Bobrov]

u(abs(v - u)<=e)

index

idx = find(abs(v - u)<=e)

Answer 2

[Paulo Silva]

Adapt this code to your purpose:

v=[1.1 2.2 3.3]'    %vector 1
u=[1.2 2.6 6]'      %vector 2
e=0.1               %error
u(u<=v+e & u>=v-e)  %values in vector 2 that are inside the limits
                    %it only compares values in the same index number

[Manjur Hossain]

Thank you Mr. Paulo Silva. You have post it at very earlier but I have implemented it today for my own work. Thank you for solution for nearest value.

Answer 3

[Stefan]

Alright, that works great!

Now, I would like to get the index where it found the values.

In the example above that would be the first value in the first column: (1,1)

Instead of returning the actual value that it found, how can I get out the index?

[Paulo Silva]

use the find function

doc find

[Jan]

"L = abs(v - u)<=e" is the logical index, "find(L)" is the numerical index.

This is explained in the "Getting Started" chapters of the documentation.

Answer 4

[Stefan]

You guys are awesome! Thanks a lot!