double equivalent_gaussian_sigma(double logp)
/* Return the approximate significance in Gaussian sigmas */
/* corresponding to a natural log probability logp */
{
double x;
if (logp < -600.0) {
x = extended_equiv_gaussian_sigma(logp);
} else {
int which, status;
double p, q, bound, mean = 0.0, sd = 1.0;
q = exp(logp);
p = 1.0 - q;
which = 2;
status = 0;
/* Convert to a sigma */
cdfnor(&which, &p, &q, &x, &mean, &sd, &status, &bound);
if (status) {
if (status == -2) {
x = 0.0;
} else if (status == -3) {
x = 38.5;
} else {
printf("\nError in cdfnor() (candidate_sigma()):\n");
printf(" status = %d, bound = %g\n", status, bound);
printf(" p = %g, q = %g, x = %g, mean = %g, sd = %g\n\n",
p, q, x, mean, sd);
exit(1);
}
}
}
if (x < 0.0)
return 0.0;
else
return x;
}
double candidate_sigma(double power, int numsum, double numtrials)
/* Return the approximate significance in Gaussian */
/* sigmas of a candidate of numsum summed powers, */
/* taking into account the number of independent trials. */
{
double x = 0.0;
if (power <= 0.0) {
return 0.0;
}
if (power > 100.0) {
double logp;
/* Use some asymtotic expansions for the chi^2 distribution */
logp = log_asymtotic_incomplete_gamma(numsum, power) -
log_asymtotic_gamma(numsum);
/* Now adjust for the number of trials */
logp += log(numtrials);
/* Convert to a sigma */
x = extended_equiv_gaussian_sigma(logp);
} else {
int which, status;
double p, q, bound, mean = 0.0, sd = 1.0, shape, scale = 1.0;
which = 1;
status = 0;
shape = (double) numsum;
x = power;
/* Determine the basic probability */
cdfgam(&which, &p, &q, &x, &shape, &scale, &status, &bound);
if (status) {
printf("\nError in cdfgam() (candidate_sigma()):\n");
printf(" status = %d, bound = %g\n", status, bound);
printf(" p = %g, q = %g, x = %g, shape = %g, scale = %g\n\n",
p, q, x, shape, scale);
exit(1);
}
/* Adjust it for the number of trials */
if (p == 1.0)
q *= numtrials;
else
q = 1.0 - pow(p, numtrials);
p = 1.0 - q;
which = 2;
status = 0;
/* Convert to a sigma */
cdfnor(&which, &p, &q, &x, &mean, &sd, &status, &bound);
if (status) {
if (status == -2) {
x = 0.0;
} else if (status == -3) {
x = 38.5;
} else {
printf("\nError in cdfnor() (candidate_sigma()):\n");
printf(" status = %d, bound = %g\n", status, bound);
printf(" p = %g, q = %g, x = %g, mean = %g, sd = %g\n\n",
p, q, x, mean, sd);
exit(1);
}
}
}
if (x < 0.0)
return 0.0;
else
return x;
}
