ISNAN  ISNAN Test for Not-a-Numbers


Usage
 
 Returns true for entries of an array that are NaN's (i.e.,
 Not-a-Numbers).  The usage is
 
    y = isnan(x)
 
 The result is a logical array of the same size as x,
 which is true if x is not-a-number, and false otherwise.
 Note that for complex or dcomplex data types that
 the result is true if either the real or imaginary parts
 are NaNs.
 