returning a unique array and comparing it with a different array.

Hello,

I have a code that generates the y-coordinates of a few points, and returns the matrix as follows.

y_cosnode =

0.5833 0.6667 0.7500 0.8333 0.9167 1.0000

0.5000 0.5833 0.6667 0.7500 0.8333 0.9167

I wanted non-repeating values so I used y_cosnode = reshape(unique(y_cosnode),1,[]) . This gives me

y_cosnode =

0.5000 0.5833 0.6667 0.7500 0.8333 0.9167 1.0000

Now, I have another matrix array, a = [0.5000 0.5833 0.6667 0.7500 1] which I would like to compare each entry values with y_cosnode.

for i=1:size(y_cosnode,2)
    [row,col] = find(y_cosnode(1,i)==a(1,:));
    col
end

col =

1

col =

1x0 empty double row vector

col =

1x0 empty double row vector

col =

4

col =

1x0 empty double row vector

col =

1x0 empty double row vector

col =

5

obviously, 0.5833 and 0.6667 should not be empty because they are in matrix a. However, when I replace the matrix array 'y_cosnode', with

y_cosnode = [0.5000 0.5833 0.6667 0.7500 0.8333 0.9167 1.0000] which are the same values, just typed by myself, I get the following results. Which is what I'm looking for.

col =

1

col =

2

col =

3

col =

4

col =

1x0 empty double row vector

col =

1x0 empty double row vector

col =

5

[Matt J]

0.5833 and 0.6667 should not be empty because they are in matrix a.

They are probably not in fact in matrix a. You're only displaying these numbers to 4 decimal places, so we cannot verify that the numbers agree beyond that.

Answer 1

[Matt J]

The whole thing can be done in one line. No need for unique, reshape, or any of the rest of it.

 result = ismembertol(a,y_cosnode(:),1e-6)

And if a nonlogical indices are really needed, you can add,

 find(result)

[Tony Haines]

Thank you for your suggestion. All i needed was to add a tolerance value.