Hi
I am facing problems with for loop in my code . The loop is supposed to run some 7400 times but it suddenly breaks after 5807 times. My first guess is that there is some where a overflow. Please find output in attachments.
#include <stdio.h>
#include <math.h>
#include <string.h>
#define SAMPLE_LENGTH 7500
float stddev(float data[], int len);
float mean(float data[], int len);
//void thresholding(float y[], int signals[], int lag, float threshold, float influence);
//void peak_detection();
int signals[SAMPLE_LENGTH];
float y[SAMPLE_LENGTH]= {0};
void setup()
{
Serial.begin(115200);
}
void loop()
{
int lag = 50;
float threshold = 5;
float influence = 0;
float filteredY[SAMPLE_LENGTH];
float avgFilter[SAMPLE_LENGTH];
float stdFilter[SAMPLE_LENGTH];
memset(signals, 0, sizeof(float) * SAMPLE_LENGTH); // set signals string to zero
memcpy(filteredY, y, sizeof(float) * SAMPLE_LENGTH); // copying input array to filteredY array
avgFilter[lag - 1] = mean(y, lag); // calling mean function
stdFilter[lag - 1] = stddev(y, lag); // calling standard deviation function
for (int i = lag; i < SAMPLE_LENGTH; i++) // loop for detecting peaks in a signal
{
Serial.println("TRACE: 2nd loop");
Serial.println(i);
if (fabsf(y[i] - avgFilter[i-1]) > threshold * stdFilter[i-1])
{
if (y[i] > avgFilter[i-1])
{
signals[i] = 1;
}
else
{
signals[i] = -1;
}
filteredY[i] = influence * y[i] + (1 - influence) * filteredY[i-1];
}
else
{
signals[i] = 0;
}
// Serial.println(signals[i]);
avgFilter[i] = mean(filteredY + i-lag, lag);
//Serial.println("TRACE: stdFilter");
//Serial.println(filteredY[i]);
stdFilter[i] = stddev(filteredY + i-lag, lag); // Error : This loop should 7400 times but actually it runs only 5807 times
// Serial.println(stdFilter[i]);
//Serial.println("TRACE: Ready");
}
while(1);
}
float mean(float data[], int len) {
float sum = 0.0, mean = 0.0;
int i;
for(i=0; i<len; ++i) {
sum += data[i];
}
mean = sum/len;
return mean;
}
float stddev(float data[], int len)
{
float the_mean = mean(data, len);
float standardDeviation = 0.0;
float temp;
int i;
for(i=0; i<len; ++i)
{
standardDeviation += pow(data[i] - the_mean, 2);
}
// Serial.println(standardDeviation);
//Serial.println(len);
temp= standardDeviation/len;
// Serial.println(temp);
// Serial.println(sqrt(temp));
return sqrt(temp);
//return sqrt(standardDeviation/len);
}
