From c71fe2979215727bf7aa20293ec2467147cd1b38 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Fri, 26 Jun 2015 16:20:13 +0200
Subject: [PATCH] simplify unit system and use floats by default

---
 artiq/__init__.py                      |   4 +-
 artiq/coredevice/core.py               |   6 +-
 artiq/devices/lda/driver.py            |  24 +--
 artiq/devices/thorlabs_tcube/driver.py |  33 ++--
 artiq/gui/moninj.py                    |   3 +-
 artiq/language/core.py                 |   2 +-
 artiq/language/units.py                | 259 +------------------------
 artiq/master/worker.py                 |   3 +-
 artiq/protocols/pyon.py                |   9 -
 artiq/test/full_stack.py               |  35 +---
 artiq/test/lda.py                      |   6 +-
 artiq/test/thorlabs_tcube.py           |   2 +-
 artiq/test/transforms.py               |  14 +-
 artiq/transforms/lower_units.py        | 190 ------------------
 artiq/transforms/tools.py              |  18 +-
 benchmarks/rpc_timing.py               |   2 +-
 examples/master/ddb.pyon               |   9 +-
 17 files changed, 43 insertions(+), 576 deletions(-)
 delete mode 100644 artiq/transforms/lower_units.py

diff --git a/artiq/__init__.py b/artiq/__init__.py
index 934cfbf49..ebdb62601 100644
--- a/artiq/__init__.py
+++ b/artiq/__init__.py
@@ -1,6 +1,4 @@
 from artiq.language.core import *
 from artiq.language.experiment import Experiment
 from artiq.language.db import *
-from artiq.language.units import check_unit
-from artiq.language.units import ps, ns, us, ms, s
-from artiq.language.units import Hz, kHz, MHz, GHz
+from artiq.language.units import *
diff --git a/artiq/coredevice/core.py b/artiq/coredevice/core.py
index 2467980f5..7f7549115 100644
--- a/artiq/coredevice/core.py
+++ b/artiq/coredevice/core.py
@@ -5,7 +5,6 @@ from artiq.language.db import *
 from artiq.language.units import ns
 
 from artiq.transforms.inline import inline
-from artiq.transforms.lower_units import lower_units
 from artiq.transforms.quantize_time import quantize_time
 from artiq.transforms.remove_inter_assigns import remove_inter_assigns
 from artiq.transforms.fold_constants import fold_constants
@@ -61,13 +60,10 @@ class Core(AutoDB):
 
     def transform_stack(self, func_def, rpc_map, exception_map,
                         debug_unparse=_no_debug_unparse):
-        lower_units(func_def, rpc_map)
-        debug_unparse("lower_units", func_def)
-
         remove_inter_assigns(func_def)
         debug_unparse("remove_inter_assigns_1", func_def)
 
-        quantize_time(func_def, self.ref_period.amount)
+        quantize_time(func_def, self.ref_period)
         debug_unparse("quantize_time", func_def)
 
         fold_constants(func_def)
diff --git a/artiq/devices/lda/driver.py b/artiq/devices/lda/driver.py
index 3f5aaa2e2..c198f04c7 100644
--- a/artiq/devices/lda/driver.py
+++ b/artiq/devices/lda/driver.py
@@ -2,7 +2,7 @@ import logging
 import ctypes
 import struct
 
-from artiq.language.units import dB, check_unit, Quantity
+from artiq.language.units import dB
 
 
 logger = logging.getLogger("lda")
@@ -47,14 +47,7 @@ class Ldasim:
         """
 
         step = self.get_att_step_size()
-
-        if isinstance(attenuation, Quantity):
-            check_unit(attenuation, "dB")
-            att = attenuation
-        else:
-            att = attenuation*dB
-
-        att = round(att/step)*step
+        att = round(attenuation/step)*step
 
         if att > self.get_att_max():
             raise ValueError("Cannot set attenuation {} > {}"
@@ -62,7 +55,7 @@ class Ldasim:
         elif att < 0*dB:
             raise ValueError("Cannot set attenuation {} < 0".format(att))
         else:
-            att = round(att.amount*4)/4. * dB
+            att = round(att*4)/4. * dB
             self._attenuation = att
 
     def ping(self):
@@ -218,14 +211,7 @@ class Lda:
         """
 
         step = self.get_att_step_size()
-
-        if isinstance(attenuation, Quantity):
-            check_unit(attenuation, "dB")
-            att = attenuation
-        else:
-            att = attenuation*dB
-
-        att = round(att/step)*step
+        att = round(attenuation/step)*step
 
         if att > self.get_att_max():
             raise ValueError("Cannot set attenuation {} > {}"
@@ -233,7 +219,7 @@ class Lda:
         elif att < 0*dB:
             raise ValueError("Cannot set attenuation {} < 0".format(att))
         else:
-            self.set(0x8d, bytes([int(round(att.amount*4))]))
+            self.set(0x8d, bytes([int(round(att*4))]))
 
     def ping(self):
         try:
diff --git a/artiq/devices/thorlabs_tcube/driver.py b/artiq/devices/thorlabs_tcube/driver.py
index b3403a03d..e7e759d5a 100644
--- a/artiq/devices/thorlabs_tcube/driver.py
+++ b/artiq/devices/thorlabs_tcube/driver.py
@@ -4,7 +4,7 @@ import struct as st
 
 import serial
 
-from artiq.language.units import V, strip_unit
+from artiq.language.units import V
 
 
 logger = logging.getLogger(__name__)
@@ -302,7 +302,7 @@ class Tcube:
 class Tpz(Tcube):
     def __init__(self, serial_dev):
         Tcube.__init__(self, serial_dev)
-        self.voltage_limit = self.get_tpz_io_settings()[0].amount
+        self.voltage_limit = self.get_tpz_io_settings()[0]
 
     def handle_message(self, msg):
         msg_id = msg.id
@@ -372,8 +372,6 @@ class Tpz(Tcube):
             between the three values 75 V, 100 V and 150 V.
         """
 
-        voltage = strip_unit(voltage, "V")
-
         if voltage < 0 or voltage > self.voltage_limit:
             raise ValueError("Voltage must be in range [0;{}]"
                              .format(self.voltage_limit))
@@ -390,7 +388,7 @@ class Tpz(Tcube):
 
         get_msg = self.send_request(MGMSG.PZ_REQ_OUTPUTVOLTS,
                                     [MGMSG.PZ_GET_OUTPUTVOLTS], 1)
-        return st.unpack("<H", get_msg.data[2:])[0]*self.voltage_limit*V/32767
+        return st.unpack("<H", get_msg.data[2:])[0]*self.voltage_limit/32767
 
     def set_output_position(self, position_sw):
         """Set output position of the piezo actuator.
@@ -532,7 +530,6 @@ class Tpz(Tcube):
             <artiq.devices.thorlabs.driver.Tpz.set_tpz_io_settings>` method.
         """
 
-        output = strip_unit(output, "V")
         volt = round(output*32767/self.voltage_limit)
         payload = st.pack("<HHH", 1, lut_index, volt)
         self.send(Message(MGMSG.PZ_SET_OUTPUTLUT, data=payload))
@@ -548,7 +545,7 @@ class Tpz(Tcube):
         get_msg = self.send_request(MGMSG.PZ_REQ_OUTPUTLUT,
                                     [MGMSG.PZ_GET_OUTPUTLUT], 1)
         (index, output) = st.unpack("<Hh", get_msg.data[2:])
-        return index, output*self.voltage_limit*V/32767
+        return index, output*self.voltage_limit/32767
 
     def set_output_lut_parameters(self, mode, cycle_length, num_cycles,
                                   delay_time, precycle_rest, postcycle_rest):
@@ -684,9 +681,6 @@ class Tpz(Tcube):
             100 V limit.
 
             150 V limit.
-
-            You can either provide this parameter as an integer or as a
-            :class:`artiq.language.units` Volt quantity (e.g. 75*V).
         :param hub_analog_input: When the T-Cube piezo driver unit is used in
             conjunction with the T-Cube Strain Gauge Reader (TSG001) on the
             T-Cube Controller Hub (TCH001), a feedback signal can be passed
@@ -706,7 +700,7 @@ class Tpz(Tcube):
             connectors.
         """
 
-        self.voltage_limit = strip_unit(voltage_limit, "V")
+        self.voltage_limit = voltage_limit
 
         if self.voltage_limit == 75:
             voltage_limit = 1
@@ -727,21 +721,21 @@ class Tpz(Tcube):
             Hub analog input. Refer to :py:meth:`set_tpz_io_settings()
             <artiq.devices.thorlabs.driver.Tpz.set_tpz_io_settings>` for the
             meaning of those parameters.
-        :rtype: a 2 elements tuple (Quantity, int)
+        :rtype: a 2 elements tuple (int, int)
         """
 
         get_msg = self.send_request(MGMSG.PZ_REQ_TPZ_IOSETTINGS,
                                     [MGMSG.PZ_GET_TPZ_IOSETTINGS], 1)
         voltage_limit, hub_analog_input = st.unpack("<HH", get_msg.data[2:6])
         if voltage_limit == 1:
-            voltage_limit = 75*V
+            voltage_limit = 75
         elif voltage_limit == 2:
-            voltage_limit = 100*V
+            voltage_limit = 100
         elif voltage_limit == 3:
-            voltage_limit = 150*V
+            voltage_limit = 150
         else:
             raise ValueError("Voltage limit should be in range [1; 3]")
-        self.voltage_limit = voltage_limit.amount
+        self.voltage_limit = voltage_limit
         return voltage_limit, hub_analog_input
 
 
@@ -1398,14 +1392,13 @@ class TpzSim:
         return self.intensity
 
     def set_tpz_io_settings(self, voltage_limit, hub_analog_input):
-        self.voltage_limit = strip_unit(voltage_limit, "V")
-
-        if self.voltage_limit not in [75, 100, 150]:
+        if voltage_limit not in [75, 100, 150]:
             raise ValueError("voltage_limit must be 75 V, 100 V or 150 V")
+        self.voltage_limit = voltage_limit
         self.hub_analog_input = hub_analog_input
 
     def get_tpz_io_settings(self):
-        return self.voltage_limit*V, self.hub_analog_input
+        return self.voltage_limit, self.hub_analog_input
 
 
 class TdcSim:
diff --git a/artiq/gui/moninj.py b/artiq/gui/moninj.py
index 280c2f909..f302cb800 100644
--- a/artiq/gui/moninj.py
+++ b/artiq/gui/moninj.py
@@ -9,7 +9,6 @@ from pyqtgraph import dockarea
 
 from artiq.tools import TaskObject
 from artiq.protocols.sync_struct import Subscriber
-from artiq.language.units import strip_unit
 
 
 logger = logging.getLogger(__name__)
@@ -170,7 +169,7 @@ class _DeviceManager:
                 if (v["module"] == "artiq.coredevice.dds"
                         and v["class"] == "DDS"):
                     channel = v["arguments"]["channel"]
-                    sysclk = strip_unit(v["arguments"]["sysclk"], "Hz")
+                    sysclk = v["arguments"]["sysclk"]
                     self.dds_widgets[channel] = _DDSWidget(
                         self.send_to_device, channel, sysclk, k)
                     self.dds_cb()
diff --git a/artiq/language/core.py b/artiq/language/core.py
index 4d73f324e..424fd07cc 100644
--- a/artiq/language/core.py
+++ b/artiq/language/core.py
@@ -231,7 +231,7 @@ def time_to_cycles(time, core=None):
     """
     if core is None:
         raise ValueError("Core device must be specified for time conversion")
-    return round64(time.amount//core.ref_period)
+    return round64(time//core.ref_period)
 
 
 def cycles_to_time(cycles, core=None):
diff --git a/artiq/language/units.py b/artiq/language/units.py
index fc8b530f6..b3af0ebc3 100644
--- a/artiq/language/units.py
+++ b/artiq/language/units.py
@@ -1,266 +1,17 @@
-"""
-Definition and management of physical units.
-
-"""
-
-from fractions import Fraction as _Fraction
-
-
-class DimensionError(Exception):
-    """Raised when attempting an operation with incompatible units.
-
-    When targeting the core device, all units are statically managed at
-    compilation time. Thus, when raised by functions in this module, this
-    exception cannot be caught in the kernel as it is raised by the compiler
-    instead.
-
-    """
-    pass
-
-
-def mul_dimension(l, r):
-    """Returns the unit obtained by multiplying unit ``l`` with unit ``r``.
-
-    Raises ``DimensionError`` if the resulting unit is not implemented.
-
-    """
-    if l is None:
-        return r
-    if r is None:
-        return l
-    if {l, r} == {"Hz", "s"}:
-        return None
-    raise DimensionError
-
-
-def _rmul_dimension(l, r):
-    return mul_dimension(r, l)
-
-
-def div_dimension(l, r):
-    """Returns the unit obtained by dividing unit ``l`` with unit ``r``.
-
-    Raises ``DimensionError`` if the resulting unit is not implemented.
-
-    """
-    if l == r:
-        return None
-    if r is None:
-        return l
-    if l is None:
-        if r == "s":
-            return "Hz"
-        if r == "Hz":
-            return "s"
-    raise DimensionError
-
-
-def _rdiv_dimension(l, r):
-    return div_dimension(r, l)
-
-
-def addsub_dimension(x, y):
-    """Returns the unit obtained by adding or subtracting unit ``l`` with
-    unit ``r``.
-
-    Raises ``DimensionError`` if ``l`` and ``r`` are different.
-
-    """
-    if x == y:
-        return x
-    else:
-        raise DimensionError
-
-
 _prefixes_str = "pnum_kMG"
-_smallest_prefix = _Fraction(1, 10**12)
-
-
-def _format(amount, unit):
-    if amount is NotImplemented:
-        return NotImplemented
-    if unit is None:
-        return amount
-    else:
-        return Quantity(amount, unit)
-
-
-class Quantity:
-    """Represents an amount in a given fundamental unit (identified by a
-    string).
-
-    The amount can be of any Python numerical type (integer, float,
-    Fraction, ...).
-    Arithmetic operations and comparisons are directly delegated to the
-    underlying numerical types.
-
-    """
-    def __init__(self, amount, unit):
-        self.amount = amount
-        self.unit = unit
-
-    def __repr__(self):
-        r_amount = self.amount
-        if isinstance(r_amount, int) or isinstance(r_amount, _Fraction):
-            r_prefix = 0
-            r_amount = r_amount/_smallest_prefix
-            if r_amount:
-                numerator = r_amount.numerator
-                while numerator % 1000 == 0 and r_prefix < len(_prefixes_str):
-                    numerator /= 1000
-                    r_amount /= 1000
-                    r_prefix += 1
-            prefix_str = _prefixes_str[r_prefix]
-            if prefix_str == "_":
-                prefix_str = ""
-            return str(r_amount) + " " + prefix_str + self.unit
-        else:
-            return str(r_amount) + " " + self.unit
-
-    def __float__(self):
-        return float(self.amount)
-
-    # mul/div
-    def _binop(self, other, opf_name, dim_function):
-        opf = getattr(self.amount, opf_name)
-        if isinstance(other, Quantity):
-            amount = opf(other.amount)
-            unit = dim_function(self.unit, other.unit)
-        else:
-            amount = opf(other)
-            unit = dim_function(self.unit, None)
-        return _format(amount, unit)
-
-    def __mul__(self, other):
-        return self._binop(other, "__mul__", mul_dimension)
-
-    def __rmul__(self, other):
-        return self._binop(other, "__rmul__", _rmul_dimension)
-
-    def __truediv__(self, other):
-        return self._binop(other, "__truediv__", div_dimension)
-
-    def __rtruediv__(self, other):
-        return self._binop(other, "__rtruediv__", _rdiv_dimension)
-
-    def __floordiv__(self, other):
-        return self._binop(other, "__floordiv__", div_dimension)
-
-    def __rfloordiv__(self, other):
-        return self._binop(other, "__rfloordiv__", _rdiv_dimension)
-
-    # unary ops
-    def __neg__(self):
-        return Quantity(self.amount.__neg__(), self.unit)
-
-    def __pos__(self):
-        return Quantity(self.amount.__pos__(), self.unit)
-
-    def __abs__(self):
-        return Quantity(abs(self.amount), self.unit)
-
-    # add/sub
-    def __add__(self, other):
-        return self._binop(other, "__add__", addsub_dimension)
-
-    def __radd__(self, other):
-        return self._binop(other, "__radd__", addsub_dimension)
-
-    def __sub__(self, other):
-        return self._binop(other, "__sub__", addsub_dimension)
-
-    def __rsub__(self, other):
-        return self._binop(other, "__rsub__", addsub_dimension)
-
-    def __mod__(self, other):
-        return self._binop(other, "__mod__", addsub_dimension)
-
-    def __rmod__(self, other):
-        return self._binop(other, "__rmod__", addsub_dimension)
-
-    # comparisons
-    def _cmp(self, other, opf_name):
-        if not isinstance(other, Quantity) or other.unit != self.unit:
-            raise DimensionError
-        return getattr(self.amount, opf_name)(other.amount)
-
-    def __lt__(self, other):
-        return self._cmp(other, "__lt__")
-
-    def __le__(self, other):
-        return self._cmp(other, "__le__")
-
-    def __eq__(self, other):
-        return self._cmp(other, "__eq__")
-
-    def __ne__(self, other):
-        return self._cmp(other, "__ne__")
-
-    def __gt__(self, other):
-        return self._cmp(other, "__gt__")
-
-    def __ge__(self, other):
-        return self._cmp(other, "__ge__")
+_smallest_prefix_exp = -12
 
 
 def _register_unit(unit, prefixes):
-    amount = _smallest_prefix
+    exponent = _smallest_prefix_exp
     for prefix in _prefixes_str:
         if prefix in prefixes:
-            quantity = Quantity(amount, unit)
             full_name = prefix + unit if prefix != "_" else unit
-            globals()[full_name] = quantity
-        amount *= 1000
+            globals()[full_name] = 10.**exponent
+        exponent += 3
+
 
 _register_unit("s", "pnum_")
 _register_unit("Hz", "_kMG")
 _register_unit("dB", "_")
 _register_unit("V", "um_k")
-
-
-def check_unit(value, unit):
-    """Checks that the value has the specified unit. Unit specification is
-    a string representing the unit without any prefix (e.g. ``s``, ``Hz``).
-    Checking for a dimensionless value (not a ``Quantity`` instance) is done
-    by setting ``unit`` to ``None``.
-
-    If the units do not match, ``DimensionError`` is raised.
-
-    This function can be used in kernels and is executed at compilation time.
-
-    There is already unit checking built into the arithmetic, so you typically
-    need to use this function only when using the ``amount`` property of
-    ``Quantity``.
-
-    """
-    if unit is None:
-        if isinstance(value, Quantity):
-            raise DimensionError
-    else:
-        if not isinstance(value, Quantity) or value.unit != unit:
-            raise DimensionError
-
-def strip_unit(value, unit):
-    """Check that the value has the specified unit and returns its amount.
-    Raises ``DimensionError`` if the units does not match.
-
-    If the passed value is not a ``Quantity``, it is assumed to be in the
-    specified unit and is returned unchanged.
-
-    If ``unit`` is ``None``, passing a ``Quantity`` as value raises
-    ``DimensionError``.
-
-    """
-    if unit is None:
-        if isinstance(value, Quantity):
-            raise DimensionError
-        else:
-            return value
-    else:
-        if isinstance(value, Quantity):
-            if value.unit != unit:
-                raise DimensionError
-            else:
-                return value.amount
-        else:
-            return value
diff --git a/artiq/master/worker.py b/artiq/master/worker.py
index acdca7908..59955d09a 100644
--- a/artiq/master/worker.py
+++ b/artiq/master/worker.py
@@ -6,7 +6,6 @@ import traceback
 import time
 
 from artiq.protocols import pyon
-from artiq.language.units import strip_unit
 from artiq.tools import (asyncio_process_wait_timeout, asyncio_process_wait,
                          asyncio_wait_or_cancel)
 
@@ -50,7 +49,7 @@ class Worker:
         avail = set(range(n_user_watchdogs + 1)) \
             - set(self.watchdogs.keys())
         wid = next(iter(avail))
-        self.watchdogs[wid] = time.monotonic() + strip_unit(t, "s")
+        self.watchdogs[wid] = time.monotonic() + t
         return wid
 
     def delete_watchdog(self, wid):
diff --git a/artiq/protocols/pyon.py b/artiq/protocols/pyon.py
index 320c691bf..3998d8bc8 100644
--- a/artiq/protocols/pyon.py
+++ b/artiq/protocols/pyon.py
@@ -14,7 +14,6 @@ The main rationale for this new custom serializer (instead of using JSON) is
 that JSON does not support Numpy and more generally cannot be extended with
 other data types while keeping a concise syntax. Here we can use the Python
 function call syntax to mark special data types.
-
 """
 
 
@@ -25,8 +24,6 @@ import tempfile
 
 import numpy
 
-from artiq.language.units import Quantity
-
 
 _encode_map = {
     type(None): "none",
@@ -39,7 +36,6 @@ _encode_map = {
     list: "list",
     dict: "dict",
     Fraction: "fraction",
-    Quantity: "quantity",
     numpy.ndarray: "nparray"
 }
 
@@ -110,10 +106,6 @@ class _Encoder:
         return "Fraction({}, {})".format(encode(x.numerator),
                                          encode(x.denominator))
 
-    def encode_quantity(self, x):
-        return "Quantity({}, {})".format(encode(x.amount),
-                                         encode(x.unit))
-
     def encode_nparray(self, x):
         r = "nparray("
         r += encode(x.shape) + ", "
@@ -147,7 +139,6 @@ _eval_dict = {
     "true": True,
 
     "Fraction": Fraction,
-    "Quantity": Quantity,
     "nparray": _nparray
 }
 
diff --git a/artiq/test/full_stack.py b/artiq/test/full_stack.py
index 83b287483..91fb1e979 100644
--- a/artiq/test/full_stack.py
+++ b/artiq/test/full_stack.py
@@ -4,7 +4,6 @@ import os
 from fractions import Fraction
 
 from artiq import *
-from artiq.language.units import DimensionError
 from artiq.coredevice import comm_tcp, core, runtime_exceptions, ttl
 from artiq.sim import devices as sim_devices
 
@@ -51,7 +50,6 @@ class _Primes(AutoDB):
 class _Misc(AutoDB):
     def build(self):
         self.input = 84
-        self.inhomogeneous_units = []
         self.al = [1, 2, 3, 4, 5]
         self.list_copy_in = [2*Hz, 10*MHz]
 
@@ -59,29 +57,10 @@ class _Misc(AutoDB):
     def run(self):
         self.half_input = self.input//2
         self.decimal_fraction = Fraction("1.2")
-        self.inhomogeneous_units.append(1000*Hz)
-        self.inhomogeneous_units.append(10*s)
         self.acc = 0
         for i in range(len(self.al)):
             self.acc += self.al[i]
         self.list_copy_out = self.list_copy_in
-        self.unit_comp = [1*MHz for _ in range(3)]
-
-    @kernel
-    def dimension_error1(self):
-        print(1*Hz + 1*s)
-
-    @kernel
-    def dimension_error2(self):
-        print(1*Hz < 1*s)
-
-    @kernel
-    def dimension_error3(self):
-        check_unit(1*Hz, "s")
-
-    @kernel
-    def dimension_error4(self):
-        delay(10*Hz)
 
 
 class _PulseLogger(AutoDB):
@@ -103,9 +82,9 @@ class _PulseLogger(AutoDB):
 
     @kernel
     def pulse(self, f, duration):
-        self.on(int(now().amount*1000000000), f)
+        self.on(int(now()*1000000000), f)
         delay(duration)
-        self.off(int(now().amount*1000000000))
+        self.off(int(now()*1000000000))
 
 
 class _Pulses(AutoDB):
@@ -229,18 +208,8 @@ class ExecutionCase(unittest.TestCase):
             uut.run()
             self.assertEqual(uut.half_input, 42)
             self.assertEqual(uut.decimal_fraction, Fraction("1.2"))
-            self.assertEqual(uut.inhomogeneous_units, [1000*Hz, 10*s])
             self.assertEqual(uut.acc, sum(uut.al))
             self.assertEqual(uut.list_copy_in, uut.list_copy_out)
-            self.assertEqual(uut.unit_comp, [1*MHz for _ in range(3)])
-            with self.assertRaises(DimensionError):
-                uut.dimension_error1()
-            with self.assertRaises(DimensionError):
-                uut.dimension_error2()
-            with self.assertRaises(DimensionError):
-                uut.dimension_error3()
-            with self.assertRaises(DimensionError):
-                uut.dimension_error4()
         finally:
             comm.close()
 
diff --git a/artiq/test/lda.py b/artiq/test/lda.py
index 9820bc226..96a1ab0b1 100644
--- a/artiq/test/lda.py
+++ b/artiq/test/lda.py
@@ -10,9 +10,9 @@ lda_serial = os.getenv("ARTIQ_LDA_SERIAL")
 
 class GenericLdaTest:
     def test_attenuation(self):
-        step = self.cont.get_att_step_size().amount
-        max = self.cont.get_att_max().amount
-        test_vector = [i*step*dB for i in range(0, int(max*int(1/step)+1))]
+        step = self.cont.get_att_step_size()
+        attmax = self.cont.get_att_max()
+        test_vector = [i*step*dB for i in range(0, int(attmax*int(1/step)+1))]
         for i in test_vector:
             with self.subTest(i=i):
                 self.cont.set_attenuation(i)
diff --git a/artiq/test/thorlabs_tcube.py b/artiq/test/thorlabs_tcube.py
index c5b0ed21d..eb2a18f97 100644
--- a/artiq/test/thorlabs_tcube.py
+++ b/artiq/test/thorlabs_tcube.py
@@ -88,7 +88,7 @@ class GenericTpzTest:
 
     def test_ouput_volts(self):
         for voltage in 5*V, 10*V, 15*V, \
-                round(self.cont.get_tpz_io_settings()[0].amount)*V:
+                round(self.cont.get_tpz_io_settings()[0])*V:
             with self.subTest(voltage=voltage):
                 test_vector = voltage
                 self.cont.set_output_volts(test_vector)
diff --git a/artiq/test/transforms.py b/artiq/test/transforms.py
index e51995ad8..31d77bd63 100644
--- a/artiq/test/transforms.py
+++ b/artiq/test/transforms.py
@@ -6,21 +6,13 @@ from artiq.coredevice import comm_dummy, core
 from artiq.transforms.unparse import unparse
 
 
-# Original code before inline:
-#
-# n = time_to_cycles(1.2345*ns)
-# ftw = self.dds.frequency_to_ftw(345*MHz)
-# f = self.dds.ftw_to_frequency(ftw)
-# phi = 1000*cycles_to_time(n)*f
-# do_someting(int(phi))
-#
 optimize_in = """
 
 def run():
-    dds_sysclk = Quantity(Fraction(1000000000, 1), 'Hz')
-    n = time_to_cycles((1.2345 * Quantity(Fraction(1, 1000000000), 's')))
+    dds_sysclk = Fraction(1000000000, 1)
+    n = time_to_cycles((1.2345 * Fraction(1, 1000000000)))
     with sequential:
-        frequency = (345 * Quantity(Fraction(1000000, 1), 'Hz'))
+        frequency = 345 * Fraction(1000000, 1)
         frequency_to_ftw_return = int((((2 ** 32) * frequency) / dds_sysclk))
     ftw = frequency_to_ftw_return
     with sequential:
diff --git a/artiq/transforms/lower_units.py b/artiq/transforms/lower_units.py
deleted file mode 100644
index eef71e564..000000000
--- a/artiq/transforms/lower_units.py
+++ /dev/null
@@ -1,190 +0,0 @@
-import ast
-from collections import defaultdict
-from copy import copy
-
-from artiq.language import units
-from artiq.transforms.tools import embeddable_func_names
-
-
-def _add_units(f, unit_list):
-    def wrapper(*args):
-        new_args = []
-        for arg, unit in zip(args, unit_list):
-            if unit is None:
-                new_args.append(arg)
-            else:
-                if isinstance(arg, list):
-                    new_args.append([units.Quantity(x, unit) for x in arg])
-                else:
-                    new_args.append(units.Quantity(arg, unit))
-        return f(*new_args)
-    return wrapper
-
-
-class _UnitsLowerer(ast.NodeTransformer):
-    def __init__(self, rpc_map):
-        self.rpc_map = rpc_map
-        # (original rpc number, (unit list)) -> new rpc number
-        self.rpc_remap = defaultdict(lambda: len(self.rpc_remap))
-        self.variable_units = dict()
-
-    def visit_Name(self, node):
-        try:
-            unit = self.variable_units[node.id]
-        except KeyError:
-            pass
-        else:
-            if unit is not None:
-                node.unit = unit
-        return node
-
-    def visit_BoolOp(self, node):
-        self.generic_visit(node)
-        us = [getattr(value, "unit", None) for value in node.values]
-        if not all(u == us[0] for u in us[1:]):
-            raise units.DimensionError
-        return node
-
-    def visit_Compare(self, node):
-        self.generic_visit(node)
-        u0 = getattr(node.left, "unit", None)
-        us = [getattr(comparator, "unit", None)
-              for comparator in node.comparators]
-        if not all(u == u0 for u in us):
-            raise units.DimensionError
-        return node
-
-    def visit_UnaryOp(self, node):
-        self.generic_visit(node)
-        if hasattr(node.operand, "unit"):
-            node.unit = node.operand.unit
-        return node
-
-    def visit_BinOp(self, node):
-        self.generic_visit(node)
-        op = type(node.op)
-        left_unit = getattr(node.left, "unit", None)
-        right_unit = getattr(node.right, "unit", None)
-        if op in (ast.Add, ast.Sub, ast.Mod):
-            unit = units.addsub_dimension(left_unit, right_unit)
-        elif op == ast.Mult:
-            unit = units.mul_dimension(left_unit, right_unit)
-        elif op in (ast.Div, ast.FloorDiv):
-            unit = units.div_dimension(left_unit, right_unit)
-        else:
-            if left_unit is not None or right_unit is not None:
-                raise units.DimensionError
-            unit = None
-        if unit is not None:
-            node.unit = unit
-        return node
-
-    def visit_Attribute(self, node):
-        self.generic_visit(node)
-        if node.attr == "amount" and hasattr(node.value, "unit"):
-            del node.value.unit
-            return node.value
-        else:
-            return node
-
-    def visit_List(self, node):
-        self.generic_visit(node)
-        if node.elts:
-            us = [getattr(elt, "unit", None) for elt in node.elts]
-            if not all(u == us[0] for u in us[1:]):
-                raise units.DimensionError
-            node.unit = us[0]
-        return node
-
-    def visit_ListComp(self, node):
-        self.generic_visit(node)
-        if hasattr(node.elt, "unit"):
-            node.unit = node.elt.unit
-        return node
-
-    def visit_Call(self, node):
-        self.generic_visit(node)
-        if node.func.id == "Quantity":
-            amount, unit = node.args
-            amount.unit = unit.s
-            return amount
-        elif node.func.id in ("now", "cycles_to_time"):
-            node.unit = "s"
-        elif node.func.id == "syscall":
-            # only RPCs can have units
-            if node.args[0].s == "rpc":
-                unit_list = tuple(getattr(arg, "unit", None)
-                                  for arg in node.args[2:])
-                rpc_n = node.args[1].n
-                node.args[1].n = self.rpc_remap[(rpc_n, (unit_list))]
-            else:
-                if any(hasattr(arg, "unit") for arg in node.args):
-                    raise units.DimensionError
-        elif node.func.id in ("delay", "at", "time_to_cycles", "watchdog"):
-            if getattr(node.args[0], "unit", None) != "s":
-                raise units.DimensionError
-        elif node.func.id == "check_unit":
-            self.generic_visit(node)
-        elif node.func.id in embeddable_func_names:
-            # must be last (some embeddable funcs may have units)
-            if any(hasattr(arg, "unit") for arg in node.args):
-                raise units.DimensionError
-        return node
-
-    def visit_Expr(self, node):
-        self.generic_visit(node)
-        if (isinstance(node.value, ast.Call)
-                and node.value.func.id == "check_unit"):
-            call = node.value
-            if (isinstance(call.args[1], ast.NameConstant)
-                    and call.args[1].value is None):
-                if hasattr(call.value.args[0], "unit"):
-                    raise units.DimensionError
-            elif isinstance(call.args[1], ast.Str):
-                if getattr(call.args[0], "unit", None) != call.args[1].s:
-                    raise units.DimensionError
-            else:
-                raise NotImplementedError
-            return None
-        else:
-            return node
-
-    def _update_target(self, target, unit):
-        if isinstance(target, ast.Name):
-            if target.id in self.variable_units:
-                if self.variable_units[target.id] != unit:
-                    raise TypeError(
-                        "Inconsistent units for variable '{}': '{}' and '{}'"
-                        .format(target.id,
-                                self.variable_units[target.id],
-                                unit))
-            else:
-                self.variable_units[target.id] = unit
-
-    def visit_Assign(self, node):
-        node.value = self.visit(node.value)
-        unit = getattr(node.value, "unit", None)
-        for target in node.targets:
-            self._update_target(target, unit)
-        return node
-
-    def visit_AugAssign(self, node):
-        value = self.visit_BinOp(ast.BinOp(
-            op=node.op, left=node.target, right=node.value))
-        unit = getattr(value, "unit", None)
-        self._update_target(node.target, unit)
-        return node
-
-    # Only dimensionless iterators are supported
-    def visit_For(self, node):
-        self.generic_visit(node)
-        self._update_target(node.target, None)
-        return node
-
-
-def lower_units(func_def, rpc_map):
-    ul = _UnitsLowerer(rpc_map)
-    ul.visit(func_def)
-    original_map = copy(rpc_map)
-    for (original_rpcn, unit_list), new_rpcn in ul.rpc_remap.items():
-        rpc_map[new_rpcn] = _add_units(original_map[original_rpcn], unit_list)
diff --git a/artiq/transforms/tools.py b/artiq/transforms/tools.py
index d9daf838f..1b68fd0f3 100644
--- a/artiq/transforms/tools.py
+++ b/artiq/transforms/tools.py
@@ -11,7 +11,7 @@ embeddable_funcs = (
     core_language.syscall, core_language.watchdog,
     range, bool, int, float, round, len,
     core_language.int64, core_language.round64,
-    Fraction, units.Quantity, units.check_unit, core_language.EncodedException
+    Fraction, core_language.EncodedException
 )
 embeddable_func_names = {func.__name__ for func in embeddable_funcs}
 
@@ -61,11 +61,6 @@ def value_to_ast(value):
         for kg in core_language.kernel_globals:
             if value is getattr(core_language, kg):
                 return ast.Name(kg, ast.Load())
-        if isinstance(value, units.Quantity):
-            return ast.Call(
-                func=ast.Name("Quantity", ast.Load()),
-                args=[value_to_ast(value.amount), ast.Str(value.unit)],
-                keywords=[], starargs=None, kwargs=None)
         raise NotASTRepresentable(str(value))
 
 
@@ -88,14 +83,6 @@ def eval_constant(node):
             numerator = eval_constant(node.args[0])
             denominator = eval_constant(node.args[1])
             return Fraction(numerator, denominator)
-        elif funcname == "Quantity":
-            amount, unit = node.args
-            amount = eval_constant(amount)
-            try:
-                unit = getattr(units, unit.id)
-            except:
-                raise NotConstant
-            return units.Quantity(amount, unit)
         else:
             raise NotConstant
     else:
@@ -105,8 +92,7 @@ def eval_constant(node):
 _replaceable_funcs = {
     "bool", "int", "float", "round",
     "int64", "round64", "Fraction",
-    "time_to_cycles", "cycles_to_time",
-    "Quantity"
+    "time_to_cycles", "cycles_to_time"
 }
 
 
diff --git a/benchmarks/rpc_timing.py b/benchmarks/rpc_timing.py
index b14da820a..33e8152d9 100644
--- a/benchmarks/rpc_timing.py
+++ b/benchmarks/rpc_timing.py
@@ -22,7 +22,7 @@ class RPCTiming(Experiment, AutoDB):
             t1 = self.core.get_rtio_time()
             self.nop(10)
             t2 = self.core.get_rtio_time()
-            self.ts[i] = float(t2.amount - t1.amount)
+            self.ts[i] = t2 - t1
 
     def run(self):
         self.bench()
diff --git a/examples/master/ddb.pyon b/examples/master/ddb.pyon
index 75c17fec8..ff6772fcb 100644
--- a/examples/master/ddb.pyon
+++ b/examples/master/ddb.pyon
@@ -60,22 +60,19 @@
         "type": "local",
         "module": "artiq.coredevice.dds",
         "class": "DDS",
-        "arguments": {"sysclk": Quantity(Fraction(1000000000, 1), "Hz"),
-                      "channel": 0}
+        "arguments": {"sysclk": 1e9, "channel": 0}
     },
     "dds1": {
         "type": "local",
         "module": "artiq.coredevice.dds",
         "class": "DDS",
-        "arguments": {"sysclk": Quantity(Fraction(1000000000, 1), "Hz"),
-                      "channel": 1}
+        "arguments": {"sysclk": 1e9, "channel": 1}
     },
     "dds2": {
         "type": "local",
         "module": "artiq.coredevice.dds",
         "class": "DDS",
-        "arguments": {"sysclk": Quantity(Fraction(1000000000, 1), "Hz"),
-                      "channel": 2}
+        "arguments": {"sysclk": 1e9, "channel": 2}
     },
 
     "qc_q1_0": {