Maths.cpp

00001 #include "Maths.h"
00002 #include "mbed.h"
00003 
00004 int Maths::comp(const void* elem1, const void* elem2)
00005 {
00006     if(*(const float*)elem1 < *(const float*)elem2)
00007         return -1;
00008     return *(const float*)elem1 > *(const float*)elem2;
00009 }
00010 
00011 float Maths::mean(float *samples, int n, int n2)
00012 {
00013     float sum = 0.0;
00014     for (int i=0; i<n2-n; i++) {
00015         sum += samples[n+i];
00016     }
00017     return sum / (float)(n2-n);
00018 }
00019 
00020 float Maths::median(float *samples, int n)
00021 {
00022     qsort(samples, n, sizeof(float), Maths::comp);
00023 
00024     return mean(samples, (n - 1)/2 - 990,(n - 1)/2 + 990);
00025 }
00026 
00027 float Maths::stdev(float data[] , int n)
00028 {
00029     float sum = 0.0, mean2, standardDeviation = 0.0;
00030     int i;
00031     mean2 = Maths::mean(data,0,n);
00032 
00033     for(i = 0; i < n; ++i)
00034         standardDeviation += pow(data[i] - mean2, 2);
00035 
00036     return sqrt(standardDeviation / n);
00037 }
00038 
00039 
00040 float Maths::meanNoOutliers(float data[] , int n)
00041 {
00042     float mean = Maths::mean(data,0,n);
00043     float stdev = Maths::stdev(data,n);
00044     float amount = 0;
00045     float sum  = 0;
00046     for(int i = 0; i < n; ++i) {
00047         if (data[i] <= mean + 1*stdev && data[i] >= mean - 1*stdev) {
00048             amount ++;
00049             sum += data[i];
00050         }
00051     }
00052     return sum/amount;
00053 
00054 
00055 }