/* file: rrgen.c
Entry number : 221
Author(s) : George Moody
Organization : MIT
email address : george at mit.edu
This program should compile without errors or warnings using:
gcc -Wall rrgen.c -lm
See http://www.physionet.org/challenge/2002/ for further information on
the CinC Challenge 2002.
This program was used to generate series rr14 and rr16 of the challenge
dataset.
This is *not* an official entry, and it doesn't follow the rules! It reads
an RR interval sequence from its standard input, and writes it in reverse
order on its standard output. Since event 1 entries are not allowed to
incorporate real physiologic time series in their outputs, participants in
event 2 were awarded full credit (2 points) for each of rr14 and rr16,
regardless of how these series were classified.
*/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define SPS 128 /* sampling frequency (determines quantization of
RR intervals; see main()) */
/* This function is called once, before generate() is called. See main()
for a description of its arguments.
*/
float *rrbuf;
long n, nrr;
void initialize(long seed, long tmax)
{
char buf[80];
if ((rrbuf = malloc(400000*sizeof(float))) == NULL)
exit(1);
for (n = 0; n < 400000 && fgets(buf, sizeof(buf), stdin) != NULL; n++)
sscanf(buf, "%f", rrbuf + n);
nrr = n;
if (n < 1)
exit(2);
return;
}
/* This function is called once per RR interval. It should return the length
of the next (simulated) RR interval in seconds.
*/
float generate(void)
{
if (n <= 0) n = nrr;
return (rrbuf[--n]);
}
int main(int argc, char **argv)
{
float t = 0.0; /* sum of intervals since the beginning of the
simulation, in seconds */
long ts = 0; /* t, in sample intervals */
long tsp = 0; /* previous value of ts */
long tmax = 24*60*60; /* 24 hours, in seconds */
long seed; /* a 32-bit random variable that can be used to
initialize the generator */
long atol();
if (argc < 2) {
fprintf(stderr, "usage: %s seed [tmax]\n", argv[0]);
exit(1);
}
seed = atol(argv[1]);
if (argc > 2)
tmax = atol(argv[2]);
initialize(seed, tmax);
while ((t += generate()) < tmax) { /* add RR interval to running time */
/* calculate and output a quantized RR interval */
ts = (long)(SPS*t + 0.5);
printf("%5.3f\n", (ts - tsp)/((float)SPS));
tsp = ts;
}
exit(0);
}