code: def _run_opf(self, HH, CC, AA, ll, uu, xmin, xmax, x0, opt):
          
          N = self._nieq
  
          if HH.nnz > 0:
              solution = qps_pips(HH, CC, AA, ll, uu, xmin, xmax, x0, opt)
          else:
              solution = qps_pips(None, CC, AA, ll, uu, xmin, xmax, x0, opt)
  
          return solution
docs: Solves the either quadratic or linear program.