Reverted HMC

Author: Christopher Fonnesbeck

pymc/step_methods/hmc.py

@@ -45,8 +45,6 @@ def __init__(self, vars, C, step_scale = .25, path_length = 2., is_cov = False,
 
         self.step_size = step_scale / n**(1/4.)
 
-        if issparse(C):
-            raise ValueError("Cannot use sparse matrix for scaling without scikits.sparse installed")
         self.potential = quad_potential(C, is_cov)
 
         self.path_length = path_length