find intersection between matrix and vector

I have a matrix and a vector:

M = 

1.0e+010 *

    0.1499  0.2998  0.4497  0.0996  0.2495
    0.3501  0.2002  0.0503  0.4004  0.2505
    0.6499  0.7998  0.9497  0.5996  0.7495
    0.8501  0.7002  0.5503  0.9004  0.7505
    1.1499  1.2998  1.4497  1.0996  1.2495
    1.3501  1.2002  1.0503  1.4004  1.2505
    1.6499  1.7998  1.9497  1.5996  1.7495
    1.8501  1.7002  1.5503  1.9004  1.7505

v =

1.0e+009 *

    1.499  2.998  4.497  5.996  7.495

How can I find the index locations in M where its value == anyone in vector v? Is there a function for this or do I have to use a FOR loop? FIND() only works on vectors.

Answer 1

[Fangjun Jiang]

help ismember

You need to be careful about the floating point comparison though.

M=magic(10);
V=1:10;
[TF,LOC]=ismember(M,V)

[Jan]

And if you run into floating point problems: http://www.mathworks.com/matlabcentral/fileexchange/23294-ismemberf

Answer 2

[Walter Roberson]

You probably will not be able to do that using ismember(). See http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F