:
On 21 October 2012 06:09, inshu chauhan <insidesh...@gmail.com> wrote:
> I am new to python and have a little problem to solve ..
> import cv
This module is not used in your code [and isn't part of the standard library].
> from math import floor, sqrt, ceil
You're only using one of these functions.
> from numpy import array, dot, subtract, add, linalg as lin
You're not using any of this.
> for p in data:
> x = p[0]
> y = p[1]
> z = p[2]
You're repeatedly making assignments in this loop, but because your
subsequent loop is not nested inside it, only the last iteration of x,
y, z will have anything done with them.
> for i in range(len(data)):
Whenever you find yourself writing
for i in range(len(seq)):
you're doing something wrong. Instead use something like
for a, b, c in seq:
or, if you really need the index,
for i, (a, b, c) in enumerate(seq):
> dist = sqrt((x[i]-x[i+1])**2 + (y[i]-y[i+1])**2 +(z[i]-z[i+1]**2))
As previously noted, you're going to be repeatedly working with the
last values of x, y and z from the previous loop here. In addition,
since x, y and z are, according to your traceback, floats, trying to
access their members as though they are sequences isn't going to work.
> return dist
This return statement is inside a loop, and will terminate the
function the first time it's called. That might not be what you want.
> def ReadPointCloud(filename):
> return [tuple(map(float, l.split()[1:4])) for l in open(filename)]
Assuming your file is along these lines:
p1 1.23 4.56 7.89
p2 9.87 6.54 3.21
... ReadPointCloud() ought to work. However, it's not very readable -
map() is sometimes useful, but usually a list comprehension is
clearer. This is better:
def ReadPointCloud(filename):
"""Return a list of 3-tuples from ``filename``."""
# not tested:
points = []
with open(filename) as f:
for line in f:
point = tuple(float(x) for x in l.split()[1:4])
points.append(point)
return points
> def main (data):
>
> for i in range(len(data)): # Finding Neighbours
> for j in range(len(data)):
> dist = calcdist(data)
> print dist
This will call calcdist() on everything in data, N**2 times [where N
is the number of points you're working with]. That's probably not what
you want.
> if __name__ == '__main__':
> data = ReadPointCloud(r'C:\Thesis\NEHreflectance_Scanner_1_part.txt')
Except for throwaway programs, it's not a good idea to hard-code
filenames like this. Better:
if __name__ == '__main__':
import sys
data = ReadPointCloud(sys.argv[1])
In summary: copy-pasting code you don't understand and mashing it
together randomly is not generally considered an effective development
technique.
-[]z.
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