Listing: numerical_solution.rb
Click
here to download original file.
#!/usr/bin/ruby -w
=begin
A numerical model for:
p(0) = 0
p'(0) = v
p''(t) = -a
=end
def numeric_solve(dt,v,a)
t = 0
p = 0
max = 0
while p >= 0
v += a * dt
p += v * dt
t += dt
max = p if p > max
end
return t,max
end
def pretty_print(*a)
while a.size > 0 do
printf("%s: %9.6f ",a.shift,a.shift)
end
puts ""
end
1.upto(6) do |n|
# starting time
st = Time.new
# think: 10 raised to the -n
dt = 10.0**-n
# solve
t,max = numeric_solve(dt,19.6,-9.8)
# get elapsed time
et = Time.new - st
# compute result error
error = (1 - (19.6/max)) * 100.0
pretty_print("dt",dt,"height",max,"error %",error,"runtime",et)
end
Share This Page