def _set_params(self, x):
assert x.size == self.num_params<EOL>self.varianceU = x[<NUM_LIT:0>]<EOL>self.varianceY = x[<NUM_LIT:1>]<EOL>self.lengthscaleU = x[<NUM_LIT:2>]<EOL>self.lengthscaleY = x[<NUM_LIT:3>]<EOL>
set the value of the parameters.