#!/usr/bin/env python
# coding: utf-8

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#Import the pyGSTi module -- you probably want this at the beginning of every notebook
import pygsti
import pygsti.construction as pc


# ## Creating Gatesets

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#There are more or less three ways to create GateSet objects in GST.
# 1) By creating an empty GateSet and populating with calls to build_gate and build_vector
# 2) By a single call to build_gateset, which automates 1)
# 3) By loading from a text-format gateset file

# We'll do each of these in turn


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#1) Create an empty gateset and build gates, rho-vectors, and E-vectors manually
stateSpace = [2] #density matrix is a 2x2 matrix
spaceLabels = [('Q0',)] #interpret the 2x2 density matrix as a single qubit named 'Q0'
gateset1 = pygsti.objects.GateSet()
gateset1.set_rhovec( pc.build_vector(stateSpace,spaceLabels,"0") )
gateset1.set_evec(   pc.build_vector(stateSpace,spaceLabels,"1") )
gateset1.set_gate('Gi', pc.build_gate(stateSpace,spaceLabels,"I(Q0)"))
gateset1.set_gate('Gx', pc.build_gate(stateSpace,spaceLabels,"X(pi/2,Q0)"))
gateset1.set_gate('Gy', pc.build_gate(stateSpace,spaceLabels,"Y(pi/2,Q0)"))
gateset1.set_identity_vec( pc.build_identity_vec(stateSpace) )
gateset1.add_spam_label(0,0,'plus')
gateset1.add_spam_label(0,-1,'minus')


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#2) Create a gateset in a single call to build_gateset
gateset2 = pc.build_gateset( [2], [('Q0',)],['Gi','Gx','Gy'], 
                             [ "I(Q0)","X(pi/2,Q0)", "Y(pi/2,Q0)"],
                             rhoExpressions=["0"], EExpressions=["1"], 
                             spamLabelDict={'plus': (0,0), 'minus': (0,-1) }) #basis="gm" )


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#3) Write a text-format gateset file and read it in.
gateset3_txt = \
"""
# Example text file describing a gateset

# State prepared, specified as a state in the Pauli basis (I,X,Y,Z)
rho
PauliVec
1/sqrt(2) 0 0 1/sqrt(2)

# State measured as yes outcome, also specified as a state in the Pauli basis
E
PauliVec
1/sqrt(2) 0 0 -1/sqrt(2)

Gi
PauliMx
1 0 0 0
0 1 0 0
0 0 1 0
0 0 0 1

Gx
PauliMx
1 0 0 0
0 1 0 0
0 0 0 1
0 0 -1 0

Gy
PauliMx
1 0 0 0
0 0 0 -1
0 0 1 0
0 1 0 0

IDENTITYVEC sqrt(2) 0 0 0
SPAMLABEL plus = rho E
SPAMLABEL minus = rho remainder
"""
open("tutorial_files/Example_Gateset.txt","w").write(gateset3_txt)

gateset3 = pygsti.io.load_gateset("tutorial_files/Example_Gateset.txt")


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#All three of the above gatesets are identical.  See for yourself by printing each one:
print "Gateset 1:\n",gateset1
print "Gateset 2:\n",gateset2
print "Gateset 3:\n",gateset3


# ## Basic Operations with Gatesets

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#Once you have a gateset, you can use the functions in GST.GateSetTools to modify them:
depol_gateset3 = gateset3.depolarize(gate_noise=0.1) # 10% depolarization on gates


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#Writing a gateset as a text file
pygsti.io.write_gateset(depol_gateset3, "tutorial_files/Example_depolarizedGateset.txt", title="My Gateset")


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#Printing more detailed information about a gateset
depol_gateset3.print_info()


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import numpy as np
def SPAM( G ):
    return np.dot( G.rhoVecs[0].T, G.EVecs[0])
dp3 = depol_gateset3.copy()
#dp3.set_evec( dp3.get_rho_vec(0), 0)
dp4 = dp3.depolarize(spam_noise=0.1)
SPAM(dp4)


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print depol_gateset3


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