Day 19/20 10/30/18-11/1/18

Modify your seismic program so that it can work with arbitrarily large data files without the use of a header line! A data file will be posted on edmodo for your to process.


/* This program reads a seismic data file and then */

/* determines the times of possible seismic events. */

#include <stdio.h>

#define FILENAME "seismic1.txt"

#define MAX_SIZE 1000

double THRESHOLD;

int main(void)

{

int val=0;

while(val==0){

printf("Enter the Threshold Number:\n");

scanf("%lf", &THRESHOLD);

if(THRESHOLD<1){

printf("Please Enter a Positive Value above 1\n");

}

else{

val++;

}}

/* Declare variables and function prototypes. */

int k, npts, short_window, long_window, count=0;

double sensor[MAX_SIZE], time[2], time_incr, short_power, long_power, ratio;

FILE *file_ptr;

double power_w(double *ptr,int n);

/* Read sensor data file. */

file_ptr = fopen(FILENAME,"r");

if (file_ptr == NULL)

printf("Error opening input file. \n");

else

{

fscanf(file_ptr,"%d %lf",&npts,&time_incr);

if (npts > MAX_SIZE)

printf("Data file too large for array. \n");

else

{

/* Read data into an array. */

for (k=0; k<=npts-1; k++)

fscanf(file_ptr,"%lf",&sensor[k]);

/* Read window sizes from the keyboard. */

printf("Enter number of points for short window: \n");

scanf("%d",&short_window);

printf("Enter number of points for long window: \n");

scanf("%d",&long_window);



/* Compute power ratios and search for events. */

for (k=long_window-1; k<=npts-1; k++)

{

short_power = power_w(&sensor[k],short_window);

long_power = power_w(&sensor[k],long_window);

ratio = short_power/long_power;

if (ratio > THRESHOLD){

printf("Possible event at %f seconds \n",time_incr*k);

count++;

time[k]=time_incr*k;}

}

for(int j=long_window-1; j<=npts-1; j++){

if((time[j]-time[j+1])==.01){

count++;

}}

printf("%d Events Occured", count);

/* Close file. */

fclose(file_ptr);

}

}

return 0;

}

/*????????????????????????????????????????????????????????????-*/

/* This function computes the average power in a specified */

/* window of a double array. */

double power_w(double *ptr, int n)

{

/* Declare and initialize variables. */

int k;

double xsquare=0;

/* Compute sum of values squared in the array x. */

for (k=0; k<=n-1; k++)

xsquare += *(ptr-k)*(*(ptr-k));

/* Return the average squared value. */

return xsquare/n;


}