don't run nlopt before running MCMC

This commit updates the chi2 script to skip minimzing the likelihood
before running the MCMC. The reason for this is that I was occasionally
seeing a linear algebra error about a singular matrix when running the
MCMC with the KDEMove which I suspect is caused by too many points being
in the same place.

1 files changed, 1 insertions, 15 deletions

diff --git a/utils/chi2 b/utils/chi2
index 9835ba3..30a0fbe 100755
--- a/utils/chi2
+++ b/utils/chi2
@@ -366,23 +366,9 @@ def do_fit(data,muon,data_mc,bins,steps,print_nll=False,walkers=100,thin=10):
     """
     nll = make_nll(data,muon,data_mc,bins,print_nll)
 
-    x0 = np.array(PRIORS)
-    opt = nlopt.opt(nlopt.LN_SBPLX, len(x0))
-    opt.set_min_objective(nll)
-    low = np.array(PRIORS_LOW)
-    high = np.array(PRIORS_HIGH)
-    opt.set_lower_bounds(low)
-    opt.set_upper_bounds(high)
-    opt.set_ftol_abs(1e-2)
-    opt.set_initial_step([0.01]*len(x0))
-
-    pos = np.empty((walkers, len(x0)),dtype=np.double)
+    pos = np.empty((walkers, len(PRIORS)),dtype=np.double)
     for i in range(pos.shape[0]):
         pos[i] = truncnorm_scaled(PRIORS_LOW,PRIORS_HIGH,PRIORS,PRIOR_UNCERTAINTIES)
-        pos[i,:] = np.clip(pos[i,:],low,high)
-        pos[i] = opt.optimize(pos[i])
-        with printoptions(precision=2, suppress=True):
-            print("pos[%i] = %s, nll = %.2f" % (i, pos[i], opt.last_optimum_value()))
 
     nwalkers, ndim = pos.shape