int
gsl_sf_lnbeta_e(const double x, const double y, gsl_sf_result * result)
{
double sgn;
int status = gsl_sf_lnbeta_sgn_e(x,y,result,&sgn);
if (sgn == -1) {
DOMAIN_ERROR(result);
}
return status;
}
CAMLprim value ml_gsl_sf_lnbeta_sgn_e(value x, value y)
{
gsl_sf_result res;
double sgn;
gsl_sf_lnbeta_sgn_e(Double_val(x), Double_val(y), &res, &sgn);
{
CAMLparam0();
CAMLlocal3(v,r,s);
r=val_of_result(&res);
s=copy_double(sgn);
v=alloc_small(2, 0);
Field(v, 0)=r;
Field(v, 1)=s;
CAMLreturn(v);
}
}
int
gsl_sf_beta_e(const double x, const double y, gsl_sf_result * result)
{
if((x > 0 && y > 0) && x < 50.0 && y < 50.0) {
/* Handle the easy case */
gsl_sf_result gx, gy, gxy;
gsl_sf_gamma_e(x, &gx);
gsl_sf_gamma_e(y, &gy);
gsl_sf_gamma_e(x+y, &gxy);
result->val = (gx.val*gy.val)/gxy.val;
result->err = gx.err * fabs(gy.val/gxy.val);
result->err += gy.err * fabs(gx.val/gxy.val);
result->err += fabs((gx.val*gy.val)/(gxy.val*gxy.val)) * gxy.err;
result->err += 2.0 * GSL_DBL_EPSILON * fabs(result->val);
return GSL_SUCCESS;
}
else if (isnegint(x) || isnegint(y)) {
DOMAIN_ERROR(result);
} else if (isnegint(x+y)) { /* infinity in the denominator */
result->val = 0.0;
result->err = 0.0;
return GSL_SUCCESS;
} else {
gsl_sf_result lb;
double sgn;
int stat_lb = gsl_sf_lnbeta_sgn_e(x, y, &lb, &sgn);
if(stat_lb == GSL_SUCCESS) {
int status = gsl_sf_exp_err_e(lb.val, lb.err, result);
result->val *= sgn;
return status;
}
else {
result->val = 0.0;
result->err = 0.0;
return stat_lb;
}
}
}
