On 05/25/2015 12:21 PM, ravas wrote:
I read an interesting comment:
"""
The coolest thing I've ever discovered about Pythagorean's Theorem is an
alternate way to calculate it. If you write a program that uses the distance
form c = sqrt(a^2 + b^2) you will suffer from the lose of half of your
available precision because the square root operation is last. A more accurate
calculation is c = a * sqrt(1 + b^2 / a^2). If a is less than b, you should
swap them and of course handle the special case of a = 0.
"""
Is this valid?
Does it apply to python?
This is a statement about floating point numeric calculations on a
computer,. As such, it does apply to Python which uses the underlying
hardware for floating point calculations.
Validity is another matter. Where did you find the quote?
Gary Herron
Any other thoughts? :D
My imagining:
def distance(A, B):
"""
A & B are objects with x and y attributes
:return: the distance between A and B
"""
dx = B.x - A.x
dy = B.y - A.y
a = min(dx, dy)
b = max(dx, dy)
if a == 0:
return b
elif b == 0:
return a
else:
return a * sqrt(1 + (b / a)**2)
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