class_docstr: Class that defines linalg operation on an array
  
  simplest version as benchmark
  
  linear algebra recipes for multivariate normal and linear
  regression calculations
code: def mhalf(self):
      evals, evecs = self.meigh
      return np.dot(np.diag(evals**0.5), evecs.T)
  
imports: import numpy
  from scipy import linalg
  from statsmodels.tools.decorators import cache_readonly
label_desc: Use image node_id 14 for calling the PlainMatrixArray obj's underlying member method code with example usage: obj.mhalf() and returns: np