6 years ago.

KNN using c++ for nRF51822, any suggestion for this output?

Hello world. After I have used this guy code.. KNN c++. and good for implement it to my module nRF51822. But if there's problem issue or not. because, there was an confusing problem. that show like this one:

1. if I'm using this

 // Sort the Points by distance from p
    sort(arr, arr+n, comparison);

but if I clear that code, to be comment session. that's compile without problem..

and the output data that's look like this one..

but after several browsing from another forum, I get this one solution.. using this function

1. include <algorithm> and std::sort that can active the sorting function..

here's the code..

#include "mbed.h"
#include "Serial.h"
#include <algorithm>  
Serial uart1(USBTX,USBRX);
using namespace std;
...

nt classifyAPoint(Point arr[], int n, int k, Point p)
{
    for (int i = 0; i < n; i++)
        arr[i].distance =
            sqrt ((arr[i].x - p.x) * (arr[i].x - p.x) + 
                  (arr[i].y - p.y) * (arr[i].y - p.y));
                  
    std::sort (arr, arr+n, comparison);
    ...
}

any suggestion, what supposed I do for the next step? this is my mbed code1 thanks, if your kindness, please give me the link code for the proper KNN that can classify data..

2. and there's also, I wanna ask too. why this code don't have same output value from this one..KNN c++ 2

#include<stdio.h>
#include "mbed.h"
#include "Serial.h"
Serial uart1(USBTX,USBRX); 
/* Function to find the cross over point (the point before
   which elements are smaller than or equal to x and after
   which greater than x)*/
int findCrossOver(int arr[], int low, int high, int x)
{
    // Base cases
  if (arr[high] <= x) // x is greater than all
    return high;
  if (arr[low] > x)  // x is smaller than all
    return low;
    
  // Find the middle point
  int mid = (low + high)/2;  /* low + (high - low)/2 */
 
  /* If x is same as middle element, then return mid */
  if (arr[mid] <= x && arr[mid+1] > x)
    return mid;
 
  /* If x is greater than arr[mid], then either arr[mid + 1]
    is ceiling of x or ceiling lies in arr[mid+1...high] */
  if(arr[mid] < x)
      return findCrossOver(arr, mid+1, high, x);
 
  return findCrossOver(arr, low, mid - 1, x); 
}  

// This function prints k closest elements to x in arr[].
// n is the number of elements in arr[]
void printKclosest(int arr[], int x, int k, int n)
{
    // Find the crossover point
    int l = findCrossOver(arr, 0, n-1, x);
    int r = l+1;   // Right index to search
    int count = 0; // To keep track of count of elements already printed
 
    // If x is present in arr[], then reduce left index
    // Assumption: all elements in arr[] are distinct
    if (arr[l] == x) l--;
 
    // Compare elements on left and right of crossover
    // point to find the k closest elements
    while (l >= 0 && r < n && count < k)
    {
        if (x - arr[l] < arr[r] - x)
            uart1.printf("%d ", arr[l--]);
        else
            uart1.printf("%d ", arr[r++]);
        count++;
    }
 
    // If there are no more elements on right side, then
    // print left elements
    while (count < k && l >= 0)
        uart1.printf("%d ", arr[l--]), count++;
 
    // If there are no more elements on left side, then
    // print right elements
    while (count < k && r < n)
        uart1.printf("%d ", arr[r++]), count++;
}

/* Driver program to check above functions */
int main()
{
   uart1.baud(9600);
   wait(0.1);
   int arr[] ={12, 16, 22, 30, 35, 39, 42,
               45, 48, 50, 53, 55, 56};
   int n = sizeof(arr)/sizeof(arr[0]);
   int x = 35, k = 4;
   printKclosest(arr, x, 4, n);
   while(1)
   {
       wait(0.1);
       uart1.printf("%d \n",printKclosest);
   }
   //return 0;
}

the output shows must be :

but my code just around this one..

3. this is I compiled it from this guy KNN c++ 3 here's my code to mbed...

#include "mbed.h"
#include <iostream>
#include "conio.h"
#include "Serial.h"
Serial uart1(USBTX,USBRX);

int main()
{
    uart1.baud(9600);
    wait(0.1);
    iint i,j,l;
    int tsc=12;
    char gen[12]={'F','M','F','F','F','M','F','M','M','F','M','F'};
    float h[12]={1.6f,2.0f,1.9f,1.88f,1.7f,1.85f,1.6f,1.7f,2.2f,1.8f,1.95f,1.9f};
    char op[12][10]={"short","tall","medium","medium","short","medium","short","short","tall","medium","medium","medium"};
 
    uart1.printf("\n Initial Set:");
    uart1.printf("\nGender\tHeight\tOutput");
    for(i=0;i<12;i++)
    {
        uart1.printf("%d, %d, %d \n",gen[i], h[i], op[i]);
    }
 
    float nh;
    char ng;
    uart1.printf("\n Enter tuple to be processed (Height,Gender) :");
    cin>>nh>>ng;
 
    int t;
    uart1.printf("\n Enter threshold:");
    cin>>t;
 
    float d[12][2],k;
 
    //calculating distance to each value in training set
    for(i=0;i<12;i++)
    {
        d[i][0]=i;
        k=h[i]-nh;
        if(k<0)
        {
            d[i][1]=-k;
        }
        else
        {
            d[i][1]=k;
        }
    }
 
    //Sorting
    for(i=0;i<11;i++)
    {
        for(j=0;j<11;j++)
        {
            if(d[j][1]>d[j+1][1])
            {
                k=d[j][1];
                d[j][1]=d[j+1][1];
                d[j+1][1]=k;
 
                l=d[j][0];
                d[j][0]=d[j+1][0];
                d[j+1][0]=l;
            }
        }
    }
 
    int nos=0;  //no of shorts
    int nom=0;  //no of mediums
    int not=0;  //no of talls
 
    uart1.printf("\nGender\tHeight\tOutput\n");
    for(i=0;i<t;i++)
    {
        l=d[i][0];
        uart1.printf("%d, %d, %d\n",gen[l],h[l],op[l]);
        if(strcmp(op[l],"short")==0)
        {
            nos++;
        }
        if(strcmp(op[l],"medium")==0)
        {
            nom++;
        }
        if(strcmp(op[l],"tall")==0)
        {
            not++;
        }
    }
 
    uart1.printf("\n No of shorts:")<<nos;
    uart1.printf("\n No of medium:")<<nom;
    uart1.printf("\n No of tall:")<<not;
 
    if(nos>nom&&nos>not)
    {
        uart1.printf("\n New Tuple is classified as Short");
    }
 
    if(nom>nos&&nom>not)
    {
        uart1.printf("\n New Tuple is classified as Medium");
    }
 
    if(not>nom&&not>nos)
    {
        uart1.printf("\n New Tuple is classified as Tall");
    }
    
    getch();
}

but there was error message like this one.

please solve this soon..