def _sync(self):
"""
If the cache is not synched, copy either the device or host value
to the host or device respectively. If cache is valid, do nothing
"""
if self._is_host_value_current and self._is_device_value_current:
return
elif self._is_host_value_current and not self._is_device_value_current:
self._device_value = DeviceScalar(self._host_value,
self._host_dtype)
elif self._is_device_value_current and not self._is_host_value_current:
self._host_value = self._device_value.value
self._host_dtype = self._host_value.dtype
else:
raise ValueError("Invalid cudf.Scalar")
def device_value(self):
if self._device_value is None:
self._device_value = DeviceScalar(self._host_value,
self._host_dtype)
return self._device_value
class Scalar(object):
def __init__(self, value, dtype=None):
"""
A GPU-backed scalar object with NumPy scalar like properties
May be used in binary operations against other scalars, cuDF
Series, DataFrame, and Index objects.
Examples
--------
>>> import cudf
>>> cudf.Scalar(42, dtype='int64')
Scalar(42, dtype=int64)
>>> cudf.Scalar(42, dtype='int32') + cudf.Scalar(42, dtype='float64')
Scalar(84.0, dtype=float64)
>>> cudf.Scalar(42, dtype='int64') + np.int8(21)
Scalar(63, dtype=int64)
>>> x = cudf.Scalar(42, dtype='datetime64[s]')
>>> y = cudf.Scalar(21, dtype='timedelta64[ns])
>>> x - y
Scalar(1970-01-01T00:00:41.999999979, dtype=datetime64[ns])
>>> cudf.Series([1,2,3]) + cudf.Scalar(1)
0 2
1 3
2 4
dtype: int64
>>> df = cudf.DataFrame({'a':[1,2,3], 'b':[4.5, 5.5, 6.5]})
>>> slr = cudf.Scalar(10, dtype='uint8')
>>> df - slr
a b
0 -9 -5.5
1 -8 -4.5
2 -7 -3.5
Parameters
----------
value : Python Scalar, NumPy Scalar, or cuDF Scalar
The scalar value to be converted to a GPU backed scalar object
dtype : np.dtype or string specifier
The data type
"""
self._host_value = None
self._host_dtype = None
self._device_value = None
if isinstance(value, DeviceScalar):
self._device_value = value
else:
self._host_value, self._host_dtype = self._preprocess_host_value(
value, dtype)
@property
def _is_host_value_current(self):
return self._host_value is not None
@property
def _is_device_value_current(self):
return self._device_value is not None
@property
def device_value(self):
if self._device_value is None:
self._device_value = DeviceScalar(self._host_value,
self._host_dtype)
return self._device_value
@property
def value(self):
if not self._is_host_value_current:
self._device_value_to_host()
return self._host_value
# todo: change to cached property
@property
def dtype(self):
if self._is_host_value_current:
if isinstance(self._host_value, str):
return np.dtype("object")
else:
return self._host_dtype
else:
return self.device_value.dtype
def is_valid(self):
if not self._is_host_value_current:
self._device_value_to_host()
return not _is_null_host_scalar(self._host_value)
def _device_value_to_host(self):
self._host_value = self._device_value._to_host_scalar()
def _preprocess_host_value(self, value, dtype):
value = to_cudf_compatible_scalar(value, dtype=dtype)
valid = not _is_null_host_scalar(value)
if dtype is None:
if not valid:
if isinstance(value, (np.datetime64, np.timedelta64)):
unit, _ = np.datetime_data(value)
if unit == "generic":
raise TypeError(
"Cant convert generic NaT to null scalar")
else:
dtype = value.dtype
else:
raise TypeError(
"dtype required when constructing a null scalar")
else:
dtype = value.dtype
dtype = np.dtype(dtype)
# temporary
dtype = np.dtype("object") if dtype.char == "U" else dtype
if not valid:
value = NA
return value, dtype
def _sync(self):
"""
If the cache is not synched, copy either the device or host value
to the host or device respectively. If cache is valid, do nothing
"""
if self._is_host_value_current and self._is_device_value_current:
return
elif self._is_host_value_current and not self._is_device_value_current:
self._device_value = DeviceScalar(self._host_value,
self._host_dtype)
elif self._is_device_value_current and not self._is_host_value_current:
self._host_value = self._device_value.value
self._host_dtype = self._host_value.dtype
else:
raise ValueError("Invalid cudf.Scalar")
def __index__(self):
if self.dtype.kind not in {"u", "i"}:
raise TypeError("Only Integer typed scalars may be used in slices")
return int(self)
def __int__(self):
return int(self.value)
def __float__(self):
return float(self.value)
def __bool__(self):
return bool(self.value)
# Scalar Binary Operations
def __add__(self, other):
return self._scalar_binop(other, "__add__")
def __radd__(self, other):
return self._scalar_binop(other, "__radd__")
def __sub__(self, other):
return self._scalar_binop(other, "__sub__")
def __rsub__(self, other):
return self._scalar_binop(other, "__rsub__")
def __mul__(self, other):
return self._scalar_binop(other, "__mul__")
def __rmul__(self, other):
return self._scalar_binop(other, "__rmul__")
def __truediv__(self, other):
return self._scalar_binop(other, "__truediv__")
def __floordiv__(self, other):
return self._scalar_binop(other, "__floordiv__")
def __rtruediv__(self, other):
return self._scalar_binop(other, "__rtruediv__")
def __mod__(self, other):
return self._scalar_binop(other, "__mod__")
def __divmod__(self, other):
return self._scalar_binop(other, "__divmod__")
def __and__(self, other):
return self._scalar_binop(other, "__and__")
def __xor__(self, other):
return self._scalar_binop(other, "__or__")
def __pow__(self, other):
return self._scalar_binop(other, "__pow__")
def __gt__(self, other):
return self._scalar_binop(other, "__gt__")
def __lt__(self, other):
return self._scalar_binop(other, "__lt__")
def __ge__(self, other):
return self._scalar_binop(other, "__ge__")
def __le__(self, other):
return self._scalar_binop(other, "__le__")
def __eq__(self, other):
return self._scalar_binop(other, "__eq__")
def __ne__(self, other):
return self._scalar_binop(other, "__ne__")
def __round__(self, n):
return self._scalar_binop(n, "__round__")
# Scalar Unary Operations
def __abs__(self):
return self._scalar_unaop("__abs__")
def __ceil__(self):
return self._scalar_unaop("__ceil__")
def __floor__(self):
return self._scalar_unaop("__floor__")
def __invert__(self):
return self._scalar_unaop("__invert__")
def __neg__(self):
return self._scalar_unaop("__neg__")
def __repr__(self):
# str() fixes a numpy bug with NaT
# https://github.com/numpy/numpy/issues/17552
return f"Scalar({str(self.value)}, dtype={self.dtype})"
def _binop_result_dtype_or_error(self, other, op):
if op in {"__eq__", "__ne__", "__lt__", "__gt__", "__le__", "__ge__"}:
return np.bool_
out_dtype = get_allowed_combinations_for_operator(
self.dtype, other.dtype, op)
# datetime handling
if out_dtype in {"M", "m"}:
if self.dtype.char in {"M", "m"} and other.dtype.char not in {
"M",
"m",
}:
return self.dtype
if other.dtype.char in {"M", "m"} and self.dtype.char not in {
"M",
"m",
}:
return other.dtype
else:
if (op == "__sub__"
and self.dtype.char == other.dtype.char == "M"):
res, _ = np.datetime_data(max(self.dtype, other.dtype))
return np.dtype("m8" + f"[{res}]")
return np.result_type(self.dtype, other.dtype)
return np.dtype(out_dtype)
def _scalar_binop(self, other, op):
if isinstance(other, (ColumnBase, Series, Index, np.ndarray)):
# dispatch to column implementation
return NotImplemented
other = to_cudf_compatible_scalar(other)
out_dtype = self._binop_result_dtype_or_error(other, op)
valid = self.is_valid and (isinstance(other, np.generic)
or other.is_valid)
if not valid:
return Scalar(None, dtype=out_dtype)
else:
result = self._dispatch_scalar_binop(other, op)
return Scalar(result, dtype=out_dtype)
def _dispatch_scalar_binop(self, other, op):
if isinstance(other, Scalar):
other = other.value
return getattr(self.value, op)(other)
def _unaop_result_type_or_error(self, op):
if op == "__neg__" and self.dtype == "bool":
raise TypeError("Boolean scalars in cuDF do not support"
" negation, use logical not")
if op in {"__ceil__", "__floor__"}:
if self.dtype.char in "bBhHf?":
return np.dtype("float32")
else:
return np.dtype("float64")
return self.dtype
def _scalar_unaop(self, op):
out_dtype = self._unaop_result_type_or_error(op)
if not self.is_valid():
result = None
else:
result = self._dispatch_scalar_unaop(op)
return Scalar(result, dtype=out_dtype)
def _dispatch_scalar_unaop(self, op):
if op == "__floor__":
return np.floor(self.value)
if op == "__ceil__":
return np.ceil(self.value)
return getattr(self.value, op)()
def astype(self, dtype):
return Scalar(self.device_value, dtype)