how to compare complex decimal number with integer value - ruby-on-rails

Question

I'm going to get all clinics that are near to my latitude and longitude. i did that with following method. the result of dist is a long value that i need to compare it with a integer value. i don't know why i get this error during the compare dist and distance which is a integer value.
this is my error:
NoMethodError (undefined method `<=' for (-2.693846638591123+0.0i):Complex):
and this is what everyhting that i did for this:
def get_clinic_list
ulat=params[:lat]
ulang=params[:lang]
distance=params[:distance]
#clinic=[]
Clinic.all.each do |clinic|
if clinic_distance(ulat,ulang,distance,clinic.id)
#doctor=DoctorProfile.find_by(user_id: clinic.user_id)
end
end
end
def clinic_distance(ulat, ulang,distance,clinic)
#clinic=Clinic.find(clinic)
diff_lat= ulat.to_f - #clinic.latitude.to_f
diff_lang= ulang.to_f - #clinic.longitude.to_f
#disc=Math.sqrt(((diff_lat*119.574)**2)+(diff_lang * Math.cos(diff_lat) * 111.320))
a=(diff_lat * 119.574) ** 2
b= diff_lang * Math.cos(diff_lat) * 111.320
c=a+b
logger.info "the c parameter is #{c}"
dist=Math.sqrt(c)
dist = dist ** 2
if dist <= distance
return true
else
return false
end
end

Answer 1

Complex numbers don't support <= or >= (although they do support ==)
Simplest solution is to get the absolute part of the number
if dist.abs <= distance

Answer 2

There was a mistake is pretty much every line of your clinic_distance method. I tried my best at correcting it, but I cannot test it without your data.
The problem isn't about Complex numbers. I don't know where this Complex number comes from, possibly from a negative c in your Math.sqrt(c).
EarthRadius = 6371 # km
OneDegree = EarthRadius * 2 * Math::PI / 360 # 1° latitude in km
def get_clinic_list
lat = params[:lat]
lon = params[:lang] # :lang???
max_distance = params[:distance] # :distance should probably be :max_distance
#clinic = [] # What do you do with this empty array?
Clinic.all.each do |clinic|
if distance_in_km(lat, lon, clinic.latitude, clinic.longitude) < max_distance
# Do you really want to keep overriding #doctor every time a clinic is found?
#doctor = DoctorProfile.find_by(user_id: clinic.user_id)
end
end
# You return every clinic, even ones far away...
end
def distance_in_km(lat1, lon1, lat2, lon2)
diff_lat = lat1.to_f - lat2.to_f
diff_lon = lon1.to_f - lon2.to_f
lat_km = diff_lat * OneDegree
lon_km = diff_lon * OneDegree * Math.cos(lat1.to_f * Math::PI / 180) # Math.cos expects a radian angle
Math.sqrt(lat_km**2 + lon_km**2)
end