Hi to all!

Im currently working with this code in the context of cosmology. When i put a prior like this (normal) it works fine and throws me the values presents in literature:

```
functions {
...
real[] GeodesicEquation (real z, // Redshift
real[] c, // Comovil Coordinates
real[] theta, // Parameters
real[] x_r, // unused data
int[] x_i
) {
real r = c[1];
real OmegaM = theta[1];
real OmegaL = theta[2];
real dr_dz = 1/E (z, OmegaM, OmegaL);
return {dr_dz};
}
}
data {
int < lower = 0 > N; // number of measurement
real < lower = 0 > zobs[N]; // Redshifts
real < lower = 0 > mobs[N]; // Supernovaes magnitude
real < lower = 0 > errorm[N]; // Supernovaes error
}
parameters {
// real < lower = 0 > m[N]; // True magnitudes
**real < lower = 0, **
** upper = 1 > OmegaM;** // Hubble local rate
**real < lower = 0, **
** upper = 1 > OmegaL;** // Local density matter
real < lower = 0 > sigma; // Error
// real < lower = 0 > alpha; //
Evolution parameter
// real < lower = 0 > beta; // Evolution parameter
}
transformed parameters {
real rr[N, 1] =
integrate_ode _rk45 (GeodesicEquation, {0.0}, 0,
zobs, {OmegaM, OmegaL},
rep_array (0.0, 0), rep_array (0, 0),
1 e - 5, 1 e - 3, 5 e2);
}
model {
**OmegaM ~ normal (0.5, 0.5);**
** OmegaL ~ normal (0.5, 0.5);**
sigma ~ lognormal (-1, 1);
for (i in 1 : N) {
if ((1 - OmegaM - OmegaL) < 0) {
mobs[i] ~
normal (5*
log10 ((1 + zobs[i])*
sin (sqrt (-(1 - OmegaM - OmegaL))*rr[i, 1])/
sqrt (-(1 - OmegaM - OmegaL))) + Ev (zobs[i]),
sigma); }
if ((1 - OmegaM - OmegaL) == 0) {
mobs[i] ~
normal (5*log10 ((1 + zobs[i])*rr[i, 1]) + Ev (zobs[i]),
sigma); }
if ((1 - OmegaM - OmegaL) > 0) {
mobs[i] ~
normal (5*
log10 ((1 + zobs[i])*
sinh (sqrt (1 - OmegaM - OmegaL)*rr[i, 1])/
sqrt (1 - OmegaM - OmegaL)) + Ev (zobs[i]), sigma); }
// mobs[i] ~ normal (m[i], errorm[i]);
}
}
```

But when i comment the line **OmegaM ~ normal (0.5, 0.5);**

** OmegaL ~ normal (0.5, 0.5);** it gives me weird thinks. Why it happens? Cause i learnt that if i define a lower and upper value in the parameter declaration, i define the prior to be uniform. There is a problem with uniform prior in HMC?