Python Forum

Not sure if i missed something,

Given a set of N measurements, (r1, r2, . . . , rN ) - reflectance array
we will initially assign the odd-numbered measurements to class 1 - find odd numbers, odd mean
and the even numbered measurements to class 2. - find even numbers , even mean
Update step: Compute the mean value (average) of the measurements within each cluster. - mean of even , mean of odd is calculated
Assignment step: Assign each measurement to the cluster with the closest mean value. - if nearest to odd mean set 1 , else 2
In case of a tie,assign the measurement to cluster 1.

import numpy as np
import math

def find_nearest(array, value):
	array = np.asarray(array)
	idx = (np.abs(array - value)).argmin()
	print(f"input value : {value}, near to mean: {array[idx]}")
	return array[idx]
	

def clusterAnalysis(reflectance):
	totalsize=np.size(reflectance)# total size
	evenarray = []
	oddarray =[]	
	for i in range(totalsize):
		if ((reflectance[i]*10)%2 ==0):
		#if ((reflectance[i]*10)%2 ==0) and (reflectance[i] %2==0):      
			evenarray.append(reflectance[i])
		else:
			oddarray.append(reflectance[i])
	np_even = np.array(evenarray)
	np_odd = np.array(oddarray)
	mean_even=np.mean(np_even)#average of even numbers in cluster 2
	mean_odd=np.mean(np_odd)# average of odd numbers in cluster 1
	print("\ngiven input: ", reflectance)
	print("total size of array: ", totalsize)
	print("even array: ",np_even)
	print("odd array: ",np_odd)
	print("mean of even class: ",mean_even)
	print("mean of odd class: ",mean_odd)
	array=[]
	clusterAssigments=[]
	
	array.append(mean_even)
	array.append(mean_odd)
	print("array for passing to find nearest : ",array)
	for i in range(totalsize):
		#print(i)
		if find_nearest(array,reflectance[i]) == mean_odd:
			clusterAssigments.append(1)
		else:
			clusterAssigments.append(2)
	clusterAssigment=np.array(clusterAssigments)
	
	return clusterAssigment
		 
print(clusterAnalysis(np.array([1.7, 1.6, 1.3, 1.3, 2.8, 1.4,2.8, 2.6, 1.6, 2.7, 1.1])))

Output:
C:\Users\testuser\Downloads\DL>python test3.py

given input:  [1.7 1.6 1.3 1.3 2.8 1.4 2.8 2.6 1.6 2.7]
total size of array:  10
even array:  [1.6 2.8 1.4 2.8 2.6 1.6]
odd array:  [1.7 1.3 1.3 2.7]
mean of even class:  2.1333333333333333
mean of odd class:  1.75
array for passing to find nearest :  [2.1333333333333333, 1.75]
input value : 1.7, near to mean: 1.75
input value : 1.6, near to mean: 1.75
input value : 1.3, near to mean: 1.75
input value : 1.3, near to mean: 1.75
input value : 2.8, near to mean: 2.1333333333333333
input value : 1.4, near to mean: 1.75
input value : 2.8, near to mean: 2.1333333333333333
input value : 2.6, near to mean: 2.1333333333333333
input value : 1.6, near to mean: 1.75
input value : 2.7, near to mean: 2.1333333333333333
[1 1 1 1 2 1 2 2 1 2]

C:\Users\testuser\Downloads\DL>python test3.py

given input:  [1.7 1.6 1.3 1.3 2.8 1.4 2.8 2.6 1.6 2.7 1.1]
total size of array:  11
even array:  [1.6 2.8 1.4 2.8 2.6 1.6]
odd array:  [1.7 1.3 1.3 2.7 1.1]
mean of even class:  2.1333333333333333
mean of odd class:  1.6199999999999999
array for passing to find nearest :  [2.1333333333333333, 1.6199999999999999]
input value : 1.7, near to mean: 1.6199999999999999
input value : 1.6, near to mean: 1.6199999999999999
input value : 1.3, near to mean: 1.6199999999999999
input value : 1.3, near to mean: 1.6199999999999999
input value : 2.8, near to mean: 2.1333333333333333
input value : 1.4, near to mean: 1.6199999999999999
input value : 2.8, near to mean: 2.1333333333333333
input value : 2.6, near to mean: 2.1333333333333333
input value : 1.6, near to mean: 1.6199999999999999
input value : 2.7, near to mean: 2.1333333333333333
input value : 1.1, near to mean: 1.6199999999999999
[1 1 1 1 2 1 2 2 1 2 1]

Best regards,
Sandeep.

GANGA SANDEEP KUMAR

Still the same problem....