From 193885078bba212c7f650b9eb8b1728e08b9d4f7 Mon Sep 17 00:00:00 2001
From: Stavros Efthymiou <35475381+stavros11@users.noreply.github.com>
Date: Tue, 17 Dec 2024 15:36:58 +0400
Subject: [PATCH 1/4] feat: implement ParametersBuilder

---
 src/qibolab/_core/components/__init__.py |  1 +
 src/qibolab/_core/components/default.py  | 19 ++++++++
 src/qibolab/_core/parameters.py          | 57 ++++++++++++++++++++++--
 src/qibolab/_core/platform/load.py       | 13 +++++-
 src/qibolab/_core/platform/platform.py   | 16 ++++---
 tests/test_parameters.py                 | 31 ++++++++++++-
 6 files changed, 125 insertions(+), 12 deletions(-)
 create mode 100644 src/qibolab/_core/components/default.py

diff --git a/src/qibolab/_core/components/__init__.py b/src/qibolab/_core/components/__init__.py
index 1b9fab688..5598bdf56 100644
--- a/src/qibolab/_core/components/__init__.py
+++ b/src/qibolab/_core/components/__init__.py
@@ -18,6 +18,7 @@
 from . import channels
 from .channels import *
 from .configs import *
+from .default import *
 
 __all__ = []
 __all__ += channels.__all__
diff --git a/src/qibolab/_core/components/default.py b/src/qibolab/_core/components/default.py
new file mode 100644
index 000000000..d219e8115
--- /dev/null
+++ b/src/qibolab/_core/components/default.py
@@ -0,0 +1,19 @@
+from .channels import AcquisitionChannel, Channel, DcChannel, IqChannel
+from .configs import AcquisitionConfig, Config, DcConfig, IqConfig
+
+__all__ = ["channel_to_config"]
+
+CHANNEL_TO_CONFIG_MAP = {
+    Channel: Config,
+    DcChannel: lambda: DcConfig(offset=0),
+    IqChannel: lambda: IqConfig(frequency=0),
+    AcquisitionChannel: lambda: AcquisitionConfig(delay=0, smearing=0),
+}
+
+
+def channel_to_config(channel: Channel) -> Config:
+    """Create a default config for a given channel.
+
+    The config type depends on the channel type.
+    """
+    return CHANNEL_TO_CONFIG_MAP[type(channel)]()
diff --git a/src/qibolab/_core/parameters.py b/src/qibolab/_core/parameters.py
index dba5aa3db..151563862 100644
--- a/src/qibolab/_core/parameters.py
+++ b/src/qibolab/_core/parameters.py
@@ -9,15 +9,18 @@
 
 from pydantic import BeforeValidator, Field, PlainSerializer, TypeAdapter
 from pydantic_core import core_schema
+from typing_extensions import NotRequired, TypedDict
 
-from .components import ChannelConfig, Config
+from .components import ChannelConfig, Config, channel_to_config
 from .execution_parameters import ConfigUpdate, ExecutionParameters
 from .identifier import QubitId, QubitPairId
-from .native import SingleQubitNatives, TwoQubitNatives
+from .instruments.abstract import Instrument, InstrumentId
+from .native import Native, NativeContainer, SingleQubitNatives, TwoQubitNatives
+from .qubits import Qubit
 from .serialize import Model, replace
 from .unrolling import Bounds
 
-__all__ = ["ConfigKinds"]
+__all__ = ["ConfigKinds", "QubitMap", "InstrumentMap", "Hardware", "ParametersBuilder"]
 
 
 def update_configs(configs: dict[str, Config], updates: list[ConfigUpdate]):
@@ -202,3 +205,51 @@ def replace(self, update: Update) -> "Parameters":
             _setvalue(d, path, val)
 
         return self.model_validate(d)
+
+
+QubitMap = dict[QubitId, Qubit]
+InstrumentMap = dict[InstrumentId, Instrument]
+
+
+class Hardware(TypedDict):
+    instruments: InstrumentMap
+    qubits: QubitMap
+    couplers: NotRequired[QubitMap]
+
+
+def _native_builder(cls, natives: set[str]) -> NativeContainer:
+    return cls(**{gate: Native() for gate in cls.model_fields.keys() & natives})
+
+
+class ParametersBuilder(Model):
+    hardware: Hardware
+    natives: set[str] = Field(default_factory=set)
+    pairs: list[str] = Field(default_factory=list)
+
+    def build(self):
+        settings = Settings()
+
+        configs = {}
+        for instrument in self.hardware.get("instruments", {}).values():
+            if hasattr(instrument, "channels"):
+                configs |= {
+                    id: channel_to_config(channel)
+                    for id, channel in instrument.channels.items()
+                }
+
+        single_qubit = {
+            q: _native_builder(SingleQubitNatives, self.natives - {"CP"})
+            for q in self.hardware.get("qubits", {})
+        }
+        coupler = {
+            q: _native_builder(SingleQubitNatives, self.natives & {"CP"})
+            for q in self.hardware.get("couplers", {})
+        }
+        two_qubit = {
+            p: _native_builder(TwoQubitNatives, self.natives) for p in self.pairs
+        }
+        native_gates = NativeGates(
+            single_qubit=single_qubit, coupler=coupler, two_qubit=two_qubit
+        )
+
+        return Parameters(settings=settings, configs=configs, native_gates=native_gates)
diff --git a/src/qibolab/_core/platform/load.py b/src/qibolab/_core/platform/load.py
index effe85e5d..a79e7adf9 100644
--- a/src/qibolab/_core/platform/load.py
+++ b/src/qibolab/_core/platform/load.py
@@ -5,6 +5,7 @@
 
 from qibo.config import raise_error
 
+from ..parameters import Parameters
 from .platform import Platform
 
 __all__ = ["create_platform", "locate_platform"]
@@ -61,7 +62,7 @@ def locate_platform(name: str, paths: Optional[list[Path]] = None) -> Path:
     return _search(name, paths)
 
 
-def create_platform(name: str) -> Platform:
+def create_platform(name: str, params: Optional[dict] = None) -> Platform:
     """A platform for executing quantum algorithms.
 
     It consists of a quantum processor QPU and a set of controlling instruments.
@@ -77,7 +78,15 @@ def create_platform(name: str) -> Platform:
 
         return create_dummy()
 
-    return _load(_search(name, _platforms_paths()))
+    path = _search(name, _platforms_paths())
+    hardware = _load(path)
+    if isinstance(hardware, Platform):
+        return hardware
+
+    if params is None:
+        return Platform.load(path, **hardware)
+
+    return Platform(**hardware, parameters=Parameters(**params))
 
 
 def available_platforms() -> list[str]:
diff --git a/src/qibolab/_core/platform/platform.py b/src/qibolab/_core/platform/platform.py
index ff1bbe73d..4ef4d292a 100644
--- a/src/qibolab/_core/platform/platform.py
+++ b/src/qibolab/_core/platform/platform.py
@@ -11,8 +11,16 @@
 from ..components.channels import Channel
 from ..execution_parameters import ExecutionParameters
 from ..identifier import ChannelId, QubitId, QubitPairId, Result
-from ..instruments.abstract import Controller, Instrument, InstrumentId
-from ..parameters import NativeGates, Parameters, Settings, Update, update_configs
+from ..instruments.abstract import Controller
+from ..parameters import (
+    InstrumentMap,
+    NativeGates,
+    Parameters,
+    QubitMap,
+    Settings,
+    Update,
+    update_configs,
+)
 from ..pulses import PulseId
 from ..qubits import Qubit
 from ..sequence import PulseSequence
@@ -21,10 +29,6 @@
 
 __all__ = ["Platform"]
 
-QubitMap = dict[QubitId, Qubit]
-QubitPairMap = list[QubitPairId]
-InstrumentMap = dict[InstrumentId, Instrument]
-
 NS_TO_SEC = 1e-9
 PARAMETERS = "parameters.json"
 
diff --git a/tests/test_parameters.py b/tests/test_parameters.py
index 5cc461c1f..a71a15164 100644
--- a/tests/test_parameters.py
+++ b/tests/test_parameters.py
@@ -4,7 +4,12 @@
 
 from qibolab._core.components.configs import Config
 from qibolab._core.native import Native, TwoQubitNatives
-from qibolab._core.parameters import ConfigKinds, Parameters, TwoQubitContainer
+from qibolab._core.parameters import (
+    ConfigKinds,
+    Parameters,
+    ParametersBuilder,
+    TwoQubitContainer,
+)
 from qibolab._core.platform.load import create_platform
 from qibolab._core.pulses.pulse import Pulse
 
@@ -104,3 +109,27 @@ def test_update():
     assert dummy.settings.nshots == 42
     assert dummy.natives.single_qubit[1].RX[0][1].amplitude == -0.123
     assert dummy.natives.single_qubit[1].RX[0][1].duration == 456.7
+
+
+def test_builder():
+    dummy = create_platform("dummy")
+
+    hardware = {
+        "instruments": dummy.instruments,
+        "qubits": dummy.qubits,
+        "couplers": dummy.couplers,
+    }
+    builder = ParametersBuilder(hardware=hardware, pairs=["0-2"])
+    parameters = builder.build()
+
+    for q in dummy.qubits:
+        assert f"{q}/drive" in parameters.configs
+        assert f"{q}/probe" in parameters.configs
+        assert f"{q}/acquisition" in parameters.configs
+        assert f"{q}/drive12" in parameters.configs
+        assert q in parameters.native_gates.single_qubit
+    for c in dummy.couplers:
+        assert f"coupler_{c}/flux" in parameters.configs
+        assert c in parameters.native_gates.coupler
+
+    assert list(parameters.native_gates.two_qubit) == [(0, 2)]

From 701093d5b14338c99ddf11d82ac756a7980549ce Mon Sep 17 00:00:00 2001
From: Stavros Efthymiou <35475381+stavros11@users.noreply.github.com>
Date: Tue, 17 Dec 2024 16:31:54 +0400
Subject: [PATCH 2/4] feat: default native gate sequences

---
 src/qibolab/_core/parameters.py | 70 +++++++++++++++++++++++++++++----
 tests/test_parameters.py        | 15 ++++++-
 2 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/src/qibolab/_core/parameters.py b/src/qibolab/_core/parameters.py
index 151563862..0e1aad989 100644
--- a/src/qibolab/_core/parameters.py
+++ b/src/qibolab/_core/parameters.py
@@ -16,6 +16,7 @@
 from .identifier import QubitId, QubitPairId
 from .instruments.abstract import Instrument, InstrumentId
 from .native import Native, NativeContainer, SingleQubitNatives, TwoQubitNatives
+from .pulses import Acquisition, Pulse, Readout, Rectangular
 from .qubits import Qubit
 from .serialize import Model, replace
 from .unrolling import Bounds
@@ -212,21 +213,70 @@ def replace(self, update: Update) -> "Parameters":
 
 
 class Hardware(TypedDict):
+    """Part of the platform that specifies the hardware configuration."""
+
     instruments: InstrumentMap
     qubits: QubitMap
     couplers: NotRequired[QubitMap]
 
 
-def _native_builder(cls, natives: set[str]) -> NativeContainer:
-    return cls(**{gate: Native() for gate in cls.model_fields.keys() & natives})
+def _gate_channel(qubit: Qubit, gate: str) -> str:
+    """Default channel that a native gate plays on."""
+    if gate in ("RX", "RX90", "CNOT"):
+        return qubit.drive
+    if gate == "RX12":
+        return qubit.drive_qudits[(1, 2)]
+    if gate == "MZ":
+        return qubit.acquisition
+    if gate in ("CP", "CZ", "iSWAP"):
+        return qubit.flux
+
+
+def _gate_sequence(qubit: Qubit, gate: str) -> Native:
+    """Default sequence corresponding to a native gate."""
+    channel = _gate_channel(qubit, gate)
+    pulse = Pulse(duration=0, amplitude=0, envelope=Rectangular())
+    if gate != "MZ":
+        return Native([(channel, pulse)])
+
+    return Native(
+        [(channel, Readout(acquisition=Acquisition(duration=0), probe=pulse))]
+    )
+
+
+def _pair_to_qubit(pair: str, qubits: QubitMap) -> Qubit:
+    """Get first qubit of a pair given in ``{q0}-{q1}`` format."""
+    q = tuple(pair.split("-"))[0]
+    try:
+        return qubits[q]
+    except KeyError:
+        return qubits[int(q)]
+
+
+def _native_builder(cls, qubit: Qubit, natives: set[str]) -> NativeContainer:
+    """Build default native gates for a given qubit or pair.
+
+    In case of pair, ``qubit`` is assumed to be the first qubit of the pair,
+    and a default pulse is added on that qubit, because at this stage we don't
+    know which qubit is the high frequency one.
+    """
+    return cls(
+        **{
+            gate: _gate_sequence(qubit, gate)
+            for gate in cls.model_fields.keys() & natives
+        }
+    )
 
 
 class ParametersBuilder(Model):
+    """Generates default ``Parameters`` for a given platform hardware
+    configuration."""
+
     hardware: Hardware
     natives: set[str] = Field(default_factory=set)
     pairs: list[str] = Field(default_factory=list)
 
-    def build(self):
+    def build(self) -> Parameters:
         settings = Settings()
 
         configs = {}
@@ -237,16 +287,20 @@ def build(self):
                     for id, channel in instrument.channels.items()
                 }
 
+        qubits = self.hardware.get("qubits", {})
         single_qubit = {
-            q: _native_builder(SingleQubitNatives, self.natives - {"CP"})
-            for q in self.hardware.get("qubits", {})
+            q: _native_builder(SingleQubitNatives, qubit, self.natives - {"CP"})
+            for q, qubit in qubits.items()
         }
         coupler = {
-            q: _native_builder(SingleQubitNatives, self.natives & {"CP"})
-            for q in self.hardware.get("couplers", {})
+            q: _native_builder(SingleQubitNatives, qubit, self.natives & {"CP"})
+            for q, qubit in self.hardware.get("couplers", {}).items()
         }
         two_qubit = {
-            p: _native_builder(TwoQubitNatives, self.natives) for p in self.pairs
+            pair: _native_builder(
+                TwoQubitNatives, _pair_to_qubit(pair, qubits), self.natives
+            )
+            for pair in self.pairs
         }
         native_gates = NativeGates(
             single_qubit=single_qubit, coupler=coupler, two_qubit=two_qubit
diff --git a/tests/test_parameters.py b/tests/test_parameters.py
index a71a15164..963090953 100644
--- a/tests/test_parameters.py
+++ b/tests/test_parameters.py
@@ -11,7 +11,7 @@
     TwoQubitContainer,
 )
 from qibolab._core.platform.load import create_platform
-from qibolab._core.pulses.pulse import Pulse
+from qibolab._core.pulses.pulse import Pulse, Readout
 
 
 def test_two_qubit_container():
@@ -119,7 +119,9 @@ def test_builder():
         "qubits": dummy.qubits,
         "couplers": dummy.couplers,
     }
-    builder = ParametersBuilder(hardware=hardware, pairs=["0-2"])
+    builder = ParametersBuilder(
+        hardware=hardware, natives=["RX", "MZ", "CZ"], pairs=["0-2"]
+    )
     parameters = builder.build()
 
     for q in dummy.qubits:
@@ -133,3 +135,12 @@ def test_builder():
         assert c in parameters.native_gates.coupler
 
     assert list(parameters.native_gates.two_qubit) == [(0, 2)]
+    sequence = parameters.native_gates.two_qubit[(0, 2)].CZ
+    assert sequence[0][0] == "0/flux"
+    assert isinstance(sequence[0][1], Pulse)
+    sequence = parameters.native_gates.single_qubit[0].RX
+    assert sequence[0][0] == "0/drive"
+    assert isinstance(sequence[0][1], Pulse)
+    sequence = parameters.native_gates.single_qubit[2].MZ
+    assert sequence[0][0] == "2/acquisition"
+    assert isinstance(sequence[0][1], Readout)

From 978034732f7059e4183506f8ac4840105695e7f2 Mon Sep 17 00:00:00 2001
From: Stavros Efthymiou <35475381+stavros11@users.noreply.github.com>
Date: Tue, 17 Dec 2024 16:45:41 +0400
Subject: [PATCH 3/4] feat: instantiate platform without parameters

---
 src/qibolab/_core/platform/load.py     |  6 +++---
 src/qibolab/_core/platform/platform.py | 15 ++++++++-------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/src/qibolab/_core/platform/load.py b/src/qibolab/_core/platform/load.py
index a79e7adf9..034d8763e 100644
--- a/src/qibolab/_core/platform/load.py
+++ b/src/qibolab/_core/platform/load.py
@@ -62,7 +62,7 @@ def locate_platform(name: str, paths: Optional[list[Path]] = None) -> Path:
     return _search(name, paths)
 
 
-def create_platform(name: str, params: Optional[dict] = None) -> Platform:
+def create_platform(name: str, parameters: Optional[Parameters] = None) -> Platform:
     """A platform for executing quantum algorithms.
 
     It consists of a quantum processor QPU and a set of controlling instruments.
@@ -83,10 +83,10 @@ def create_platform(name: str, params: Optional[dict] = None) -> Platform:
     if isinstance(hardware, Platform):
         return hardware
 
-    if params is None:
+    if parameters is None:
         return Platform.load(path, **hardware)
 
-    return Platform(**hardware, parameters=Parameters(**params))
+    return Platform(**hardware, parameters=parameters)
 
 
 def available_platforms() -> list[str]:
diff --git a/src/qibolab/_core/platform/platform.py b/src/qibolab/_core/platform/platform.py
index 4ef4d292a..e5f61bc25 100644
--- a/src/qibolab/_core/platform/platform.py
+++ b/src/qibolab/_core/platform/platform.py
@@ -16,6 +16,7 @@
     InstrumentMap,
     NativeGates,
     Parameters,
+    ParametersBuilder,
     QubitMap,
     Settings,
     Update,
@@ -310,13 +311,13 @@ def load(
         if couplers is None:
             couplers = {}
 
-        return cls(
-            name=name,
-            parameters=Parameters.model_validate_json((path / PARAMETERS).read_text()),
-            instruments=instruments,
-            qubits=qubits,
-            couplers=couplers,
-        )
+        hardware = {"instruments": instruments, "qubits": qubits, "couplers": couplers}
+        try:
+            parameters = Parameters.model_validate_json((path / PARAMETERS).read_text())
+        except FileNotFoundError:
+            parameters = ParametersBuilder(hardware=hardware).build()
+
+        return cls(name=name, parameters=parameters, **hardware)
 
     def dump(self, path: Path):
         """Dump platform."""

From 8725616e32b4a31a0fb53623e504300a693ab560 Mon Sep 17 00:00:00 2001
From: Stavros Efthymiou <35475381+stavros11@users.noreply.github.com>
Date: Tue, 17 Dec 2024 18:08:10 +0400
Subject: [PATCH 4/4] fix: include LO and mixer configs

---
 src/qibolab/_core/components/__init__.py |  1 -
 src/qibolab/_core/components/default.py  | 19 ------------
 src/qibolab/_core/parameters.py          | 38 ++++++++++++++++++++----
 3 files changed, 32 insertions(+), 26 deletions(-)
 delete mode 100644 src/qibolab/_core/components/default.py

diff --git a/src/qibolab/_core/components/__init__.py b/src/qibolab/_core/components/__init__.py
index 5598bdf56..1b9fab688 100644
--- a/src/qibolab/_core/components/__init__.py
+++ b/src/qibolab/_core/components/__init__.py
@@ -18,7 +18,6 @@
 from . import channels
 from .channels import *
 from .configs import *
-from .default import *
 
 __all__ = []
 __all__ += channels.__all__
diff --git a/src/qibolab/_core/components/default.py b/src/qibolab/_core/components/default.py
deleted file mode 100644
index d219e8115..000000000
--- a/src/qibolab/_core/components/default.py
+++ /dev/null
@@ -1,19 +0,0 @@
-from .channels import AcquisitionChannel, Channel, DcChannel, IqChannel
-from .configs import AcquisitionConfig, Config, DcConfig, IqConfig
-
-__all__ = ["channel_to_config"]
-
-CHANNEL_TO_CONFIG_MAP = {
-    Channel: Config,
-    DcChannel: lambda: DcConfig(offset=0),
-    IqChannel: lambda: IqConfig(frequency=0),
-    AcquisitionChannel: lambda: AcquisitionConfig(delay=0, smearing=0),
-}
-
-
-def channel_to_config(channel: Channel) -> Config:
-    """Create a default config for a given channel.
-
-    The config type depends on the channel type.
-    """
-    return CHANNEL_TO_CONFIG_MAP[type(channel)]()
diff --git a/src/qibolab/_core/parameters.py b/src/qibolab/_core/parameters.py
index 0e1aad989..bf0d3a321 100644
--- a/src/qibolab/_core/parameters.py
+++ b/src/qibolab/_core/parameters.py
@@ -11,9 +11,21 @@
 from pydantic_core import core_schema
 from typing_extensions import NotRequired, TypedDict
 
-from .components import ChannelConfig, Config, channel_to_config
+from .components import (
+    AcquisitionChannel,
+    AcquisitionConfig,
+    Channel,
+    ChannelConfig,
+    Config,
+    DcChannel,
+    DcConfig,
+    IqChannel,
+    IqConfig,
+    IqMixerConfig,
+    OscillatorConfig,
+)
 from .execution_parameters import ConfigUpdate, ExecutionParameters
-from .identifier import QubitId, QubitPairId
+from .identifier import ChannelId, QubitId, QubitPairId
 from .instruments.abstract import Instrument, InstrumentId
 from .native import Native, NativeContainer, SingleQubitNatives, TwoQubitNatives
 from .pulses import Acquisition, Pulse, Readout, Rectangular
@@ -268,6 +280,22 @@ def _native_builder(cls, qubit: Qubit, natives: set[str]) -> NativeContainer:
     )
 
 
+def _channel_config(id: ChannelId, channel: Channel) -> dict[ChannelId, Config]:
+    """Default configs correspondign to a channel."""
+    if isinstance(channel, DcChannel):
+        return {id: DcConfig(offset=0)}
+    if isinstance(channel, AcquisitionChannel):
+        return {id: AcquisitionConfig(delay=0, smearing=0)}
+    if isinstance(channel, IqChannel):
+        configs = {id: IqConfig(frequency=0)}
+        if channel.lo is not None:
+            configs[channel.lo] = OscillatorConfig(frequency=0, power=0)
+        if channel.mixer is not None:
+            configs[channel.mixer] = IqMixerConfig(frequency=0, power=0)
+        return configs
+    return {id: Config()}
+
+
 class ParametersBuilder(Model):
     """Generates default ``Parameters`` for a given platform hardware
     configuration."""
@@ -282,10 +310,8 @@ def build(self) -> Parameters:
         configs = {}
         for instrument in self.hardware.get("instruments", {}).values():
             if hasattr(instrument, "channels"):
-                configs |= {
-                    id: channel_to_config(channel)
-                    for id, channel in instrument.channels.items()
-                }
+                for id, channel in instrument.channels.items():
+                    configs |= _channel_config(id, channel)
 
         qubits = self.hardware.get("qubits", {})
         single_qubit = {