harold.haroldcompanion

harold.haroldcompanion(somearray)

Takes a 1D numpy array or list and returns the companion matrix of the monic polynomial of somearray. Hence [0.5,1,2] will be first converted to [1,2,4].

Examples

>>> haroldcompanion([2,4,6])
array([[ 0.,  1.],
       [-3., -2.]])
>>> haroldcompanion([1,3])
array([[-3.]])
>>> haroldcompanion([1])
array([], dtype=float64)