Compare two numbers x and y, and return True if they are close within the requested relative/absolute tolerance. This function only returns True/False, never NA.
More specifically, isclose(x, y) is True if either of the following are true:
x == y(including the case when x and y are NAs),
abs(x - y) <= atol + rtol * abs(y)and neither x nor y are NA
The tolerance parameters
atol must be positive floats,
and cannot be expressions.