unique with tolerance

Similar to Unique, gives unique element within a tolerance.

Description

UNIQUETOL Unique element within a tolerance.

[Y,I,J] = UNIQUETOL(X,TOL) is very similar to UNIQUE, but allows an additional tolerance input, TOL. TOL can be taken as the total absolute difference between similar elements. TOL must be a none negative scalar. If not provided, TOL is assumed to be 0, which makes UNIQUETOL identical to UNIQUE.
 
    UNIQUETOL(...,'ROWS')
    UNIQUETOL(...,'FIRST')
    UNIQUETOL(...,'LAST')
    These expressions are identical to the UNIQUE counterparts.

• MATLAB release: MATLAB 7.10 (2010a)

[Siyi Deng]

Here's an example:

x = [1 2 3;
       1+eps 2 3;
       2 3 4];

[y1,i1,j1] = unique(x,'rows')

y =

    1.0000 2.0000 3.0000
    1.0000 2.0000 3.0000
    2.0000 3.0000 4.0000

i1 =

     1
     2
     3

j1 =

     1
     2
     3

[y2,i2,j2] = uniquetol(x,10*eps,'rows')

y2 =

     1 2 3
     2 3 4

i2 =

     1
     3

j2 =

     1
     1
     2

[Richard Crozier]