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pls help me with this prog

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  pls help me with this prog inshu chauhan <insideshoes@gmail.com> - 2012-10-19 10:40 +0200
    Re: pls help me with this prog rusi <rustompmody@gmail.com> - 2012-10-19 06:06 -0700
    Re: pls help me with this prog Tim Roberts <timr@probo.com> - 2012-10-20 19:33 -0700
    Re: pls help me with this prog 88888 Dihedral <dihedral88888@googlemail.com> - 2012-10-21 01:09 -0700
    Re: pls help me with this prog 88888 Dihedral <dihedral88888@googlemail.com> - 2012-10-21 01:09 -0700

#31716 — pls help me with this prog

in this prog I have written a code to calculate teh centre of a given 3D data..

but i want to calculate it for every 3 points not the whole data, but
instead of giving me centre for every 3 data the prog is printing the
centre 3 times...

import cv
from math import floor, sqrt, ceil
from numpy import array, dot, subtract, add, linalg as lin




def CalcCentre(data):
    centre = array([0,0,0])
    count = 0
    n = 0
    for p in data[n:n+3]:
        centre = add(centre, array(p[:3]))
        count += 1
        centre = dot(1./count, centre)
        return centre
    n += 1
def ReadPointCloud(filename):
    f = open(filename)
    result = []
    for l in f:
        sp = l.split()
        t = tuple(map(float, sp[1:4]))
        result.append(t)
    return result

def main (data):


    j = 0
    for  i in data[:3]:
        while j != 3:
         centre = CalcCentre(data)
         j += 1
         print centre


if __name__ == '__main__':
    data = ReadPointCloud(r'Z:\data\NEHreflectance_Scanner 1_part.txt')

main(data)




PLS HELP ;;;;

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#31739

Dont know what your code does/tries to do. Anyway some points:

On Oct 19, 1:40 pm, inshu chauhan <insidesh...@gmail.com> wrote:
> in this prog I have written a code to calculate teh centre of a given 3D data..
>
> but i want to calculate it for every 3 points not the whole data, but
> instead of giving me centre for every 3 data the prog is printing the
> centre 3 times...
>
> import cv
> from math import floor, sqrt, ceil
> from numpy import array, dot, subtract, add, linalg as lin
>
> def CalcCentre(data):
>     centre = array([0,0,0])
>     count = 0
>     n = 0
>     for p in data[n:n+3]:
>         centre = add(centre, array(p[:3]))
>         count += 1
>         centre = dot(1./count, centre)
>         return centre
>     n += 1



The return makes the for iterate only once
And n += 1 will never be reached

>    t = tuple(map(float, sp[1:4]))
drops the sp[0] element.

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#31835

inshu chauhan <insideshoes@gmail.com> wrote:
>
>but i want to calculate it for every 3 points not the whole data, but
>instead of giving me centre for every 3 data the prog is printing the
>centre 3 times...
>
>def main (data):
>    j = 0
>    for  i in data[:3]:
>        while j != 3:
>         centre = CalcCentre(data)
>         j += 1
>         print centre

This loop doesn't do what you think it does.  Think about the problem you
have to solve.  You have a set of data.  You want to operate on the whole
set, 3 points at a time.  What this loop does is grab the first three
points (only), then calculates the center on the entire list three times.

You want something like:

    # As long as there is data in the list:
    while data:
        # Split the list into two parts: first 3 and the rest.
        first3, data = data[3:],data[3:]
        # Operate on the first three.
        print CalcCenter( first3 )

To make it a little more resilient, you might make sure that len(data) is a
multiple of 3, or at least stop when it is shorter than 3.

To be more clever, you can write a function that returns 3 at a time:

def N_at_a_time( iter, n ):
    while len(iter) >= n:
        yield iter[:n]
        iter = iter[n:]

Now you can do this:

def main(data):
    for first3 in N_at_a_time(data, 3):
        print CalcCenter(first3)
-- 
Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.

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#31838

On Friday, October 19, 2012 4:40:42 PM UTC+8, inshu chauhan wrote:
> in this prog I have written a code to calculate teh centre of a given 3D data..
> 
> 
> 
> but i want to calculate it for every 3 points not the whole data, but
> 
> instead of giving me centre for every 3 data the prog is printing the
> 
> centre 3 times...
> 
> 
> 
> import cv
> 
> from math import floor, sqrt, ceil
> 
> from numpy import array, dot, subtract, add, linalg as lin
> 
> 
> 
> 
> 
> 
> 
> 
> 
> def CalcCentre(data):
> 
>     centre = array([0,0,0])
> 
>     count = 0
> 
>     n = 0
> 
>     for p in data[n:n+3]:
> 
>         centre = add(centre, array(p[:3]))
> 
>         count += 1
> 
>         centre = dot(1./count, centre)
> 
>         return centre
> 
>     n += 1
> 
> def ReadPointCloud(filename):
> 
>     f = open(filename)
> 
>     result = []
> 
>     for l in f:
> 
>         sp = l.split()
> 
>         t = tuple(map(float, sp[1:4]))
> 
>         result.append(t)
> 
>     return result
> 
> 
> 
> def main (data):
> 
> 
> 
> 
> 
>     j = 0
> 
>     for  i in data[:3]:
> 
>         while j != 3:
> 
>          centre = CalcCentre(data)
> 
>          j += 1
> 
>          print centre
> 
> 
> 
> 
> 
> if __name__ == '__main__':
> 
>     data = ReadPointCloud(r'Z:\data\NEHreflectance_Scanner 1_part.txt')
> 
> 
> 
> main(data)
> 
> 
> 
> 
> 
> 
> 
> 
> 
> PLS HELP ;;;;

# assume data is a list of 3 n numbers, n!=0

n3=data.length()
n=n/3
x=sum(data[0:n3:3])/n
y=sum(data[1:n3:3])/n
z=sum(data[2:n3:3])/n #(x,y,z)

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#31839

On Friday, October 19, 2012 4:40:42 PM UTC+8, inshu chauhan wrote:
> in this prog I have written a code to calculate teh centre of a given 3D data..
> 
> 
> 
> but i want to calculate it for every 3 points not the whole data, but
> 
> instead of giving me centre for every 3 data the prog is printing the
> 
> centre 3 times...
> 
> 
> 
> import cv
> 
> from math import floor, sqrt, ceil
> 
> from numpy import array, dot, subtract, add, linalg as lin
> 
> 
> 
> 
> 
> 
> 
> 
> 
> def CalcCentre(data):
> 
>     centre = array([0,0,0])
> 
>     count = 0
> 
>     n = 0
> 
>     for p in data[n:n+3]:
> 
>         centre = add(centre, array(p[:3]))
> 
>         count += 1
> 
>         centre = dot(1./count, centre)
> 
>         return centre
> 
>     n += 1
> 
> def ReadPointCloud(filename):
> 
>     f = open(filename)
> 
>     result = []
> 
>     for l in f:
> 
>         sp = l.split()
> 
>         t = tuple(map(float, sp[1:4]))
> 
>         result.append(t)
> 
>     return result
> 
> 
> 
> def main (data):
> 
> 
> 
> 
> 
>     j = 0
> 
>     for  i in data[:3]:
> 
>         while j != 3:
> 
>          centre = CalcCentre(data)
> 
>          j += 1
> 
>          print centre
> 
> 
> 
> 
> 
> if __name__ == '__main__':
> 
>     data = ReadPointCloud(r'Z:\data\NEHreflectance_Scanner 1_part.txt')
> 
> 
> 
> main(data)
> 
> 
> 
> 
> 
> 
> 
> 
> 
> PLS HELP ;;;;

# assume data is a list of 3 n numbers, n!=0

n3=data.length()
n=n/3
x=sum(data[0:n3:3])/n
y=sum(data[1:n3:3])/n
z=sum(data[2:n3:3])/n #(x,y,z)

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