modify core

randomquantumcircuit.py

@@ -177,7 +177,7 @@ def generate_circuits(self, depth):
 # height
 n = 8
 # circuit depth
-depth = 16
+depth = 10
 
 
 maxbonddimension = 100

rqc/core/__init__.py

@@ -1,3 +1,4 @@
 
 from .circuit2d import *
 from .overlap import *
+from .measure import *

rqc/core/measure.py

@@ -0,0 +1,75 @@
+# -*- coding: utf-8 -*-
+# @Author: guochu
+# @Date:   2020-11-09 10:55:24
+# @Last Modified by:   guochu
+# @Last Modified time: 2020-11-09 11:23:08
+from numpy.random import uniform
+from numpy import sqrt
+from rqc.tensor import astensor 
+from .circuit2d import OneBodyGate
+
+__all__ = ['OneBodyObserver']
+
+def _discrete_sample(l):
+	s = sum(l)
+	# print('sum is', s)
+	if (abs(s) < 1.0e-12):
+		# print('s is', s)
+		raise ValueError('error in measure.')
+	l1 = [None]*(len(l)+1)
+	l1[0] = 0.
+	for i in range(len(l)):
+		l1[i+1] = l1[i] + l[i]/s
+	s = uniform(low=0., high=1.)
+	for i in range(len(l1)-1):
+		if (s >= l1[i] and s < l1[i+1]):
+			return i
+	raise NotImplementedError('should not be here.')
+
+
+class OneBodyObserver:
+	"""docstring for OneBodyObserver"""
+	def __init__(self, key):
+		if len(key) != 2:
+			raise ValueError('wrong position for one body gate.')
+		for s in key:
+			if not isinstance(s, int):
+				raise TypeError('position must be integer type.')
+		self.key = tuple(key)
+
+	def apply(self, state, maxbonddimension=2000, svdcutoff=1.0e-8, verbose=1):
+		up = astensor([[1., 0.], [0., 0.]])
+		down = astensor([[0., 0.], [0., 1.]])
+		up_gate = OneBodyGate(self.key, up)
+		# ms = close_peps(state, state, {self.key:up})
+		state_1 = state.copy()
+		up_gate.apply(state, maxbonddimension=maxbonddimension, svdcutoff=svdcutoff, verbose=verbose)
+		s = state_1.cross(state, conj=True, scale_factor=1.)
+		tol = 1.0e-6
+		if s.imag > tol:
+			warnings.warn('the imaginary part of result is larger than'+str(tol))
+		s = abs(s.real)
+		l = [s, abs(1-s)]
+		i = _discrete_sample(l)
+		# print('probability is', s, 'istate is', i)
+		if i==0:
+			state[self.key] = up.contract(state[self.key], ((1,), (0,)))
+			state[self.key] /= sqrt(l[i])
+		else:
+			state[self.key] = down.contract(state[self.key], ((1,), (0,)))
+			state[self.key] /= sqrt(l[i])		
+		self.istate = i
+		self.probability = l[i]
+
+	def apply_and_collect(self, state, result, maxbonddimension=2000, svdcutoff=1.0e-8, verbose=1):
+		self.apply(state, maxbonddimension, svdcutoff, verbose=verbose)
+		result.append(self.result)
+
+
+	@property
+	def name(self):
+		return 'Q:Z' + str(self.key)
+
+	@property
+	def result(self):
+		return (self.name, self.istate)

rqc/core/peps.py

@@ -44,9 +44,10 @@ def __setitem__(self, key, value):
 		self.data[self.__sgi(key)] = astensor(value)
 
 	def copy(self):
-		r = type(self)(self.m, self.n)
-		for i in range(self.m):
-			for j in range(self.n):
+		m, n = self.shape
+		r = type(self)(self.shape)
+		for i in range(m):
+			for j in range(n):
 				r[(i, j)] = self[(i, j)].copy()
 		return r