ichuang / pyqsp Goto Github PK

The code description says "ham_sim.py shows an example of how the angle sequence for Hamiltonian simulation can be found." but the file seems to be missing from the repository.

Hi,

Thank you for open-sourcing this code!

I would love to understand why QuantumSignalProcessingPhases is non-deterministic for the same polynomial.
For example:

import pyqsp 
from pyqsp import angle_sequence
from numpy.polynomial.polynomial import Polynomial

poly = pyqsp.poly.PolySign().generate(degree=5, delta=10.0)
print(repr(poly))
for i in range(5): 
  phis = pyqsp.angle_sequence.QuantumSignalProcessingPhases(poly)
  print(phis)

Produces:

[pyqsp.poly.PolySign] degree=5, delta=10.0
[PolyTaylorSeries] max [0.9] is at [1.]: normalizing
[PolyTaylorSeries] average error = 0.21930741075851684 in the domain [-1, 1] using degree 5
TargetPolynomial([ 0.     ,  2.42154,  0.     , -2.8077 ,  0.     ,  1.28616], domain=[-1,  1], window=[-1,  1])
[-0.1953070756439737, 0.2597197965037532, -1.0753701746905036, -1.0753701746905047, 0.2597197965037523, 1.3754892511509227]
[-0.08086819012861554, 0.2692339694770634, -0.748204652312621, -0.7482046523126189, 0.2692339694770627, 1.4899281366662787]
[-0.08086819012861554, 0.2692339694770634, -0.748204652312621, -0.7482046523126189, 0.2692339694770627, 1.4899281366662787]
[-1.3974820311242748, -0.5688243732627165, 0.9553489505562665, 0.9553489505562655, -0.5688243732627172, 0.17331429567062237]
[-1.3754892511509236, -0.25971979650375365, 1.0753701746905024, 1.0753701746905044, -0.2597197965037502, 0.19530707564397418]

Maybe I'm wrong about my expectation around it being deterministic?
It is absolutely not urgent, I'm working through the Martyn et al Grand unification of quantum algorithms paper and ran into this issue.

Thank you!

Hello,

First of all, thank you for making pyqsp public. The Quantum Signal Processing theory is already phenomenal, but, as evidenced by Chao et al., and as shown by the existance of pyqsp in the first place, it would be very complicated to get started in practice without this package.

Per the introduction section of the README, since the package borrows and extends techniques from multiple publications, I would appreciate if there were explicit citation instructions, to reference when using the package in the context of other work.

Hi!

I was trying to play with the example for an arbitrary function specified as a string using a numpy expression when run into an issue for the code line (poly + Polynomial([0, ] * poly.degree() + [eps / 2, ]))

TypeError: unsupported operand type(s) for +: 'StringPolynomial' and 'Polynomial'

My code followed exactly the example provided in the repo:

poly = pyqsp.poly.StringPolynomial("np.cos(3*x)", 6)
ang_seq = pyqsp.angle_sequence.QuantumSignalProcessingPhases(poly)
pyqsp.response.PlotQSPResponse(ang_seq, target=poly, signal_operator="Wx")

Are there missing lines of code that convert a string representation of a function to a function or am I doing something wrong here?