ruby - What does the quo method do? -

consider following methods, found in byar gem:

## # calculate lower boundary observed cases def self.lower_bound(obs, z_value = z_value)   return 0 if obs == 0   obs * (1 - 1.quo(9 * obs) - z_value.quo(3 * math.sqrt(obs))) ** 3 end  ## # calculate upper boundary observed cases def self.upper_bound(obs, z_value = z_value)   obs = obs + 1   obs * (1 - 1.quo(9 * obs) + z_value.quo(3 * math.sqrt(obs))) ** 3 end 

i port these methods javascript, unsure quo does.

quo method defined on numeric class (and redefined in float class), calculates quotient of receiver given argument. in other words, x.quo(y) equivalent x / y, more precise.

the difference here comes in when x , y fixnums (ie. integer value):

> (1 / 2) => 0 > (1 / 2).class => fixnum > 1.quo(2) => (1/2) > 1.quo(2).class => rational > 1.quo(2.5) => 0.4 > 1.quo(2.5).class => float 

basically, quo ensures result of division expressed accurately returing rational or float, depending on receiver , argument.

in javascript, there isn't distinction between different types of numbers, , division returns floating point number if necessary, first method can expressed as:

obs * math.pow(1 - 1 / (9 * obs) - z_value / (3 * math.sqrt(obs)), 3)