Array elements that are NaN
TF = isnan(A)
TF = isnan(A) returns an array the same size as A containing logical 1 (true) where the elements of A are NaNs and logical 0 (false) where they are not. For a complex number z, isnan(z) returns 1 if either the real or imaginary part of z is NaN, and 0 if both the real and imaginary parts are finite or Inf.
For any real A, exactly one of the three quantities isfinite(A), isinf(A), and isnan(A) is equal to one.