Python Itertools.product with floats

Asked Apr 06 '17 at 11:00

Active Apr 06 '17 at 11:22

Viewed 284 times

I have the following problem:

I have three lists:

radius=3.0
fcr_size=2.0
x1 = np.arange(0,5.0+0.3,0.3) 
y1 = np.arange(0,5.0+0.3,0.3)
z1 = np.arange(0,5.0+2.0,2.0)

for coords in itertools.product(x1,y1,z1):
        if radius < distance.euclidean([0,0,0],coords) <= (radius+fcr_size):
            xyz_pattern.append(coords)

Why is the output of the float prducts something like this?:

(3.2999999999999998, 2.6999999999999997, 2.0)
(3.2999999999999998, 2.6999999999999997, 4.0)
(3.2999999999999998, 2.6999999999999997, 6.0)
(3.2999999999999998, 3.0, 0.0)
(3.2999999999999998, 3.0, 2.0)
(3.2999999999999998, 3.0, 4.0)
(3.2999999999999998, 3.0, 6.0)
(3.2999999999999998, 3.2999999999999998, 0.0)
(3.2999999999999998, 3.2999999999999998, 2.0)
(3.2999999999999998, 3.2999999999999998, 4.0)
(3.2999999999999998, 3.2999999999999998, 6.0)

Why not something like this:

(3.3, 2.7, 2.0), (3.3, 2.7, 4.0), (3.3, 2.7, 6.0) .....

edited Apr 06 '17 at 11:22

asked Apr 06 '17 at 11:00

Varlor

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what you want in the output ? – Surajano Apr 06 '17 at 11:02
The list elements of x1 and y1 are [0.0,0.3,0.6,0.9,1.2,1.5,1.8,2.1,2.4,2.7,3.0,3.3,3.6,3.9,4.2,4.5,4.8,5.1] and z1 [0,2.,4.,6.]. Why is the prdouct of the floats not : (3.3, 2.7, 2.0) for example – Varlor Apr 06 '17 at 11:06
1

That's how floating point numbers work. – xrisk Apr 06 '17 at 11:24
But why arnt they dispayed like this before when i print(np.arange(0,5.0+0.3,0.3)) ? – Varlor Apr 06 '17 at 11:27
Thank you, i checked it and see what the problem is :) – Varlor Apr 07 '17 at 12:43
What was the issue? I'm running into the same problem. Why are the floats changing from one step to the next? – John Mansell Mar 29 '21 at 23:12

Python Itertools.product with floats

0 Answers0