PulseSequencer.py

# coding: utf-8
'''
Quantum Gate Language Module

Copyright 2013 Raytheon BBN Technologies

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
'''

from __future__ import unicode_literals
from copy import copy
import json
import numpy as np
import operator
from collections import OrderedDict
from functools import reduce
from builtins import str

from . import ChannelLibrary, PulseShapes

from collections import namedtuple

class Pulse(namedtuple("Pulse", ["label", "channel", "length", "amp", "phase", "frequency",
                                 "frameChange", "shapeParams", "isTimeAmp",
                                 "isZero", "ignoredStrParams"])):
    __slots__ = ()

    def __new__(cls, label, channel, shapeParams, amp=1.0, phase=0, frameChange=0, ignoredStrParams=[]):
        if hasattr(channel, 'frequency'):
            frequency = channel.frequency
        else:
            frequency = 0
        requiredParams = ['length', 'shapeFun']
        for param in requiredParams:
            if param not in shapeParams.keys():
                raise NameError("shapeParams must include {0}".format(param))
        isTimeAmp = (shapeParams['shapeFun'] == PulseShapes.constant)
        isZero = (amp == 0)
        return super(cls, Pulse).__new__(cls, label, channel, shapeParams['length'], amp, phase, frequency, frameChange, shapeParams, isTimeAmp, isZero, ignoredStrParams)

    def __str__(self):
        kwvals = []
        # object parameters outside of shapeParams
        for param in ["amp", "phase", "frameChange"]:
            if param not in self.ignoredStrParams:
                kwvals.append("{0}={1}".format(param, getattr(self, param)))
        # parameters inside shapeParams
        for n, v in self.shapeParams.items():
            if (n not in self.ignoredStrParams and
                    n in self.channel.pulseParams and
                    self.channel.pulseParams[n] != v):
                kwvals.append("{0}={1}".format(n, v))
        if kwvals:
            kwstr = ", " + ", ".join(kwvals)
        else:
            kwstr = ""
        return '{0}({1}{2})'.format(self.label, self.channel.label, kwstr)

    def _repr_pretty_(self, p, cycle):
        p.text(str(self))

    def hashshape(self):
        return hash(frozenset(self.shapeParams.items()))

    def __add__(self, other):
        if self.channel != other.channel:
            raise NameError(
                "Can only concatenate pulses acting on the same channel")
        return CompositePulse("", [self, other])

    # unary negation inverts the pulse amplitude and frame change
    def __neg__(self):
        return Pulse(self.label, self.channel, copy(self.shapeParams),
                     -self.amp, self.phase, -self.frameChange)

    def __mul__(self, other):
        """ Overload multiplication of Pulses as a "tensor" operator"""
        return self.promote() * other.promote()

    def promote(self):
        # promote a Pulse to a PulseBlock
        return PulseBlock(self)

    @property
    def shape(self):
        params = copy(self.shapeParams)
        params['samplingRate'] = self.channel.physChan.samplingRate
        params.pop('shapeFun')
        return self.shapeParams['shapeFun'](**params)


def TAPulse(label,
            channel,
            length,
            amp,
            phase=0,
            frameChange=0,
            ignoredStrParams=None):
    """
    Creates a time/amplitude pulse with the given pulse length and amplitude
    """
    params = {'length': length, 'shapeFun': PulseShapes.constant}
    if ignoredStrParams:
        ignoredStrParams.append('shapeFun')
    else:
        ignoredStrParams = ['shapeFun']
    return Pulse(label, channel, params, amp, phase, frameChange, ignoredStrParams)


class CompositePulse(namedtuple("CompositePulse", ["label", "pulses"])):
    '''
    A sequential series of pulses that reside within one time bin of a pulse block
    '''
    __slots__ = ()

    def __str__(self):
        if self.label != "":
            return self.label
        else:
            return "+".join([str(p) for p in self.pulses])

    def _repr_pretty_(self, p, cycle):
        p.text(str(self))

    def __add__(self, other):
        if self.channel != other.channel:
            raise NameError(
                "Can only concatenate pulses acting on the same channel")
        if hasattr(other, 'pulses'):
            return CompositePulse("", self.pulses + other.pulses)
        else:
            return CompositePulse("", self.pulses + [other])

    def __mul__(self, other):
        return self.promote() * other.promote()

    def promote(self):
        # promote a CompositePulse to a PulseBlock
        return PulseBlock(self)

    @property
    def channel(self):
        # Assume that the first pulse in the composite contains the channel information
        return self.pulses[0].channel

    @property
    def length(self):
        return sum(p.length for p in self.pulses)

    @property
    def frameChange(self):
        return sum(p.frameChange for p in self.pulses)

    @property
    def isZero(self):
        return all(p.isZero for p in self.pulses)


class PulseBlock(object):
    '''
    The basic building block for pulse sequences. This is what we can concatenate together to make sequences.
    We overload the * operator so that we can combine pulse blocks on different channels.
    We overload the + operator to concatenate pulses on the same channel.
    '''

    def __init__(self, *pulses):
        self.alignment = 'left'
        self.pulses = OrderedDict([(pulse.channel, pulse) for pulse in pulses])
        # The maximum length for any channel on this block
        self.length = max(p.length for p in self.pulses.values())
        self.label = None

    def __repr__(self):
        return "Pulses " + ";".join([
            str(pulse) for pulse in self.pulses.values()
        ]) + " alignment: {0}".format(self.alignment)

    def __str__(self):
        labelPart = "{0}: ".format(self.label) if self.label else ""
        return labelPart + "*".join(
            [str(pulse) for pulse in self.pulses.values()])

    def _repr_pretty_(self, p, cycle):
        labelPart = "{0}: ".format(self.label) if self.label else ""
        p.text(labelPart + "⊗ ".join([str(pulse)
                                      for pulse in self.pulses.values()]))

    # Overload the multiplication operator to combine pulse blocks
    def __mul__(self, rhs):
        # make sure RHS is a PulseBlock
        rhs = rhs.promote()

        # copy PulseBlock so we don't modify other references
        result = copy(self)
        result.pulses = copy(self.pulses)
        for (k, v) in rhs.pulses.items():
            if k in result.pulses.keys():
                raise NameError(
                    "Attempted to multiply pulses acting on the same space")
            else:
                result.pulses[k] = v
        result.length = max(self.length, rhs.length)
        return result

    def __eq__(self, other):
        if isinstance(other, self.__class__):
            # ignore label in equality testing
            mydict = self.__dict__.copy()
            otherdict = other.__dict__.copy()
            mydict.pop('label')
            otherdict.pop('label')
            return mydict == otherdict
        return False

    def __ne__(self, other):
        return not self == other

    # PulseBlocks don't need to be promoted, so just return self
    def promote(self):
        return self

    @property
    def channel(self):
        return self.pulses.keys()

def align(pulseBlock, mode="center"):
    # make sure we have a PulseBlock
    pulseBlock = pulseBlock.promote()
    pulseBlock.alignment = mode
    return pulseBlock