code: def _frobenius(A, B):
      """
      Frobenius inner product of A and B: Trace(A'B)
  
      Does not check
      shape of x to ensure it's square.
      """
      return (A * B).sum()
  
imports: import numpy
  from numpy.linalg import svd
  from .reml import orth
label_desc: Use image node_id 2 for calling a global function with example usage: _frobenius(A, B) and returns: unknown