Speed up parameter resolution for cirq.Duration (#6270)

cirq-core/cirq/value/duration.py

@@ -13,14 +13,14 @@
 # limitations under the License.
 """A typed time delta that supports picosecond accuracy."""
 
-from typing import AbstractSet, Any, Dict, Optional, Tuple, TYPE_CHECKING, Union
+from typing import AbstractSet, Any, Dict, Optional, Tuple, TYPE_CHECKING, Union, List
 import datetime
 
 import sympy
 import numpy as np
 
 from cirq import protocols
-from cirq._compat import proper_repr
+from cirq._compat import proper_repr, cached_method
 from cirq._doc import document
 
 if TYPE_CHECKING:
@@ -79,48 +79,53 @@ def __init__(
             >>> print(cirq.Duration(micros=1.5 * sympy.Symbol('t')))
             (1500.0*t) ns
         """
+        self._time_vals: List[_NUMERIC_INPUT_TYPE] = [0, 0, 0, 0]
+        self._multipliers = [1, 1000, 1000_000, 1000_000_000]
         if value is not None and value != 0:
             if isinstance(value, datetime.timedelta):
                 # timedelta has microsecond resolution.
-                micros += int(value / datetime.timedelta(microseconds=1))
+                self._time_vals[2] = int(value / datetime.timedelta(microseconds=1))
             elif isinstance(value, Duration):
-                picos += value._picos
+                self._time_vals = value._time_vals
             else:
                 raise TypeError(f'Not a `cirq.DURATION_LIKE`: {repr(value)}.')
-
-        val = picos + nanos * 1000 + micros * 1000_000 + millis * 1000_000_000
-        self._picos: _NUMERIC_OUTPUT_TYPE = float(val) if isinstance(val, np.number) else val
+        input_vals = [picos, nanos, micros, millis]
+        self._time_vals = _add_time_vals(self._time_vals, input_vals)
 
     def _is_parameterized_(self) -> bool:
-        return protocols.is_parameterized(self._picos)
+        return protocols.is_parameterized(self._time_vals)
 
     def _parameter_names_(self) -> AbstractSet[str]:
-        return protocols.parameter_names(self._picos)
+        return protocols.parameter_names(self._time_vals)
 
     def _resolve_parameters_(self, resolver: 'cirq.ParamResolver', recursive: bool) -> 'Duration':
-        return Duration(picos=protocols.resolve_parameters(self._picos, resolver, recursive))
+        return _duration_from_time_vals(
+            protocols.resolve_parameters(self._time_vals, resolver, recursive)
+        )
 
+    @cached_method
     def total_picos(self) -> _NUMERIC_OUTPUT_TYPE:
         """Returns the number of picoseconds that the duration spans."""
-        return self._picos
+        val = sum(a * b for a, b in zip(self._time_vals, self._multipliers))
+        return float(val) if isinstance(val, np.number) else val
 
     def total_nanos(self) -> _NUMERIC_OUTPUT_TYPE:
         """Returns the number of nanoseconds that the duration spans."""
-        return self._picos / 1000
+        return self.total_picos() / 1000
 
     def total_micros(self) -> _NUMERIC_OUTPUT_TYPE:
         """Returns the number of microseconds that the duration spans."""
-        return self._picos / 1000_000
+        return self.total_picos() / 1000_000
 
     def total_millis(self) -> _NUMERIC_OUTPUT_TYPE:
         """Returns the number of milliseconds that the duration spans."""
-        return self._picos / 1000_000_000
+        return self.total_picos() / 1000_000_000
 
     def __add__(self, other) -> 'Duration':
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return Duration(picos=self._picos + other._picos)
+        return _duration_from_time_vals(_add_time_vals(self._time_vals, other._time_vals))
 
     def __radd__(self, other) -> 'Duration':
         return self.__add__(other)
@@ -129,86 +134,94 @@ def __sub__(self, other) -> 'Duration':
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return Duration(picos=self._picos - other._picos)
+        return _duration_from_time_vals(
+            _add_time_vals(self._time_vals, [-x for x in other._time_vals])
+        )
 
     def __rsub__(self, other) -> 'Duration':
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return Duration(picos=other._picos - self._picos)
+        return _duration_from_time_vals(
+            _add_time_vals(other._time_vals, [-x for x in self._time_vals])
+        )
 
     def __mul__(self, other) -> 'Duration':
         if not isinstance(other, (int, float, sympy.Expr)):
             return NotImplemented
-        return Duration(picos=self._picos * other)
+        if other == 0:
+            return _duration_from_time_vals([0] * 4)
+        return _duration_from_time_vals([x * other for x in self._time_vals])
 
     def __rmul__(self, other) -> 'Duration':
         return self.__mul__(other)
 
     def __truediv__(self, other) -> Union['Duration', float]:
         if isinstance(other, (int, float, sympy.Expr)):
-            return Duration(picos=self._picos / other)
+            new_time_vals = [x / other for x in self._time_vals]
+            return _duration_from_time_vals(new_time_vals)
 
         other_duration = _attempt_duration_like_to_duration(other)
         if other_duration is not None:
-            return self._picos / other_duration._picos
+            return self.total_picos() / other_duration.total_picos()
 
         return NotImplemented
 
     def __eq__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos == other._picos
+        return self.total_picos() == other.total_picos()
 
     def __ne__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos != other._picos
+        return self.total_picos() != other.total_picos()
 
     def __gt__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos > other._picos
+        return self.total_picos() > other.total_picos()
 
     def __lt__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos < other._picos
+        return self.total_picos() < other.total_picos()
 
     def __ge__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos >= other._picos
+        return self.total_picos() >= other.total_picos()
 
     def __le__(self, other):
         other = _attempt_duration_like_to_duration(other)
         if other is None:
             return NotImplemented
-        return self._picos <= other._picos
+        return self.total_picos() <= other.total_picos()
 
     def __bool__(self):
-        return bool(self._picos)
+        return bool(self.total_picos())
 
     def __hash__(self):
-        if isinstance(self._picos, (int, float)) and self._picos % 1000000 == 0:
-            return hash(datetime.timedelta(microseconds=self._picos / 1000000))
-        return hash((Duration, self._picos))
+        if isinstance(self.total_picos(), (int, float)) and self.total_picos() % 1000000 == 0:
+            return hash(datetime.timedelta(microseconds=self.total_picos() / 1000000))
+        return hash((Duration, self.total_picos()))
 
     def _decompose_into_amount_unit_suffix(self) -> Tuple[int, str, str]:
+        picos = self.total_picos()
         if (
-            isinstance(self._picos, sympy.Mul)
-            and len(self._picos.args) == 2
-            and isinstance(self._picos.args[0], (sympy.Integer, sympy.Float))
+            isinstance(picos, sympy.Mul)
+            and len(picos.args) == 2
+            and isinstance(picos.args[0], (sympy.Integer, sympy.Float))
         ):
-            scale = self._picos.args[0]
-            rest = self._picos.args[1]
+            scale = picos.args[0]
+            rest = picos.args[1]
         else:
-            scale = self._picos
+            scale = picos
             rest = 1
 
         if scale % 1000_000_000 == 0:
@@ -234,7 +247,7 @@ def _decompose_into_amount_unit_suffix(self) -> Tuple[int, str, str]:
         return amount * rest, unit, suffix
 
     def __str__(self) -> str:
-        if self._picos == 0:
+        if self.total_picos() == 0:
             return 'Duration(0)'
         amount, _, suffix = self._decompose_into_amount_unit_suffix()
         if not isinstance(amount, (int, float, sympy.Symbol)):
@@ -257,3 +270,21 @@ def _attempt_duration_like_to_duration(value: Any) -> Optional[Duration]:
     if isinstance(value, (int, float)) and value == 0:
         return Duration()
     return None
+
+
+def _add_time_vals(
+    val1: List[_NUMERIC_INPUT_TYPE], val2: List[_NUMERIC_INPUT_TYPE]
+) -> List[_NUMERIC_INPUT_TYPE]:
+    ret: List[_NUMERIC_INPUT_TYPE] = []
+    for i in range(4):
+        if val1[i] and val2[i]:
+            ret.append(val1[i] + val2[i])
+        else:
+            ret.append(val1[i] or val2[i])
+    return ret
+
+
+def _duration_from_time_vals(time_vals: List[_NUMERIC_INPUT_TYPE]):
+    ret = Duration()
+    ret._time_vals = time_vals
+    return ret

cirq-core/cirq/value/duration_test.py

@@ -168,9 +168,11 @@ def test_sub():
 def test_mul():
     assert Duration(picos=2) * 3 == Duration(picos=6)
     assert 4 * Duration(picos=3) == Duration(picos=12)
+    assert 0 * Duration(picos=10) == Duration()
 
     t = sympy.Symbol('t')
     assert t * Duration(picos=3) == Duration(picos=3 * t)
+    assert 0 * Duration(picos=t) == Duration(picos=0)
 
     with pytest.raises(TypeError):
         _ = Duration() * Duration()