code: def symmetrify(A, upper=False):
      
      if use_linalg_cython:
          _symmetrify_cython(A, upper)
      else:
          _symmetrify_numpy(A, upper)
docs: Take the square matrix A and make it symmetrical by copting elements from
      the lower half to the upper
  
      works IN PLACE.
  
      note: tries to use cython, falls back to a slower numpy version