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apache--tvm/python/tvm/runtime/_tensor.py
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chore: import upstream snapshot with attribution
2026-07-13 13:36:25 +08:00

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Python

# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you 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.
# pylint: disable=invalid-name, unused-import, redefined-outer-name
# ruff: noqa: F401, RUF005
"""Runtime Tensor API"""
import ctypes
import warnings
from typing import Optional
import numpy as np
try:
import ml_dtypes
except ImportError:
ml_dtypes = None
import tvm_ffi
from tvm_ffi import DLDeviceType, device
import tvm
from tvm.runtime import Device
from . import _ffi_api
def from_dlpack(ext_tensor):
"""
Convert an external tensor to an Tensor.
Parameters
----------
ext_tensor : object
The external tensor to convert.
require_alignment : int
The minimum required alignment to check for the tensor.
require_contiguous : bool
Whether to check for contiguous memory.
"""
# TODO(tvm-team): change to require_alignment=0 and require_contiguous=False
# once we update the compiler generated code to guard against misaligned access.
return tvm_ffi.from_dlpack(
ext_tensor,
require_alignment=64,
require_contiguous=True,
)
@tvm_ffi.register_object("ffi.Tensor")
class Tensor(tvm_ffi.core.Tensor):
"""Lightweight Tensor class of TVM runtime.
Strictly this is only an Array Container (a buffer object)
No arthimetic operations are defined.
All operations are performed by TVM functions.
The goal is not to re-build yet another array library.
Instead, this is a minimal data structure to demonstrate
how can we use TVM in existing project which might have their own array containers.
"""
def __setitem__(self, in_slice, value):
"""Set ndarray value"""
if (
not isinstance(in_slice, slice)
or in_slice.start is not None
or in_slice.stop is not None
):
raise ValueError("Array only support set from numpy array")
if isinstance(value, Tensor):
if not value.same_as(self):
value.copyto(self)
elif isinstance(value, np.ndarray | np.generic):
self.copyfrom(value)
else:
raise TypeError(f"type {type(value)} not supported")
def copyfrom(self, source_array):
"""Perform a synchronous copy from the array.
Parameters
----------
source_array : array_like
The data source we should like to copy from.
Returns
-------
arr : Tensor
Reference to self.
"""
if isinstance(source_array, Tensor):
source_array.copyto(self)
return self
if not isinstance(source_array, np.ndarray):
try:
source_array = np.array(source_array, dtype=self.dtype)
except Exception:
raise TypeError(
f"array must be an array_like data, type {type(source_array)} is not supported"
)
t = tvm_ffi.dtype(self.dtype)
shape, dtype = self.shape, self.dtype
if t.lanes > 1:
shape = shape + (t.lanes,)
t = t.with_lanes(1)
dtype = str(t)
if source_array.shape != shape:
raise ValueError(
f"array shape do not match the shape of Tensor {source_array.shape} vs {shape}"
)
numpy_str_map = tvm_ffi.dtype._NUMPY_DTYPE_TO_STR
np_dtype_str = (
numpy_str_map[source_array.dtype]
if source_array.dtype in numpy_str_map
else str(source_array.dtype)
)
if (not source_array.flags["C_CONTIGUOUS"]) or (
dtype == "bfloat16" or dtype != np_dtype_str
):
if dtype == "bfloat16":
source_array = np.frombuffer(source_array.tobytes(), "uint16")
source_array = np.ascontiguousarray(
source_array, dtype="uint16" if dtype == "bfloat16" else dtype
)
if self.dtype.startswith("float4_e2m1fn"):
# we need to pack the input data when converting to float4_e2m1fn type,
data_bits = source_array.view(dtype="uint8").flatten()
if data_bits.size % 2:
data_bits = np.pad(data_bits, (0, 1), mode="constant", constant_values=0)
data_bits = data_bits.reshape(-1, 2)
packed = ((data_bits[:, 0] & 0x0F) << 4) | (data_bits[:, 1] & 0x0F)
source_array = packed.astype(np.int8)
assert source_array.flags["C_CONTIGUOUS"]
data = source_array.ctypes.data_as(ctypes.c_void_p)
nbytes = source_array.size * source_array.dtype.itemsize
_ffi_api.TVMTensorCopyFromBytes(self, data, nbytes)
return self
def __repr__(self):
# exception safety handling for chandle=None
if self.__chandle__() == 0:
return type(self).__name__ + "(chandle=None)"
res = f"<tvm.runtime.Tensor shape={self.shape}, {self.device}>\n"
res += self.numpy().__repr__()
return res
def __str__(self):
return str(self.numpy())
def numpy(self):
"""Convert this array to numpy array
Returns
-------
np_arr : numpy.ndarray
The corresponding numpy array.
"""
t = tvm_ffi.dtype(self.dtype)
shape, dtype = self.shape, self.dtype
old_dtype = dtype
if t.lanes > 1:
shape = shape + (t.lanes,)
t = t.with_lanes(1)
dtype = str(t)
if dtype == "int4":
dtype = "int8"
if dtype in [
"bfloat16",
"float8_e3m4",
"float8_e4m3",
"float8_e4m3b11fnuz",
"float8_e4m3fn",
"float8_e4m3fnuz",
"float8_e5m2",
"float8_e5m2fnuz",
"float8_e8m0fnu",
"float6_e2m3fn",
"float6_e3m2fn",
"float4_e2m1fn",
]:
if ml_dtypes is None:
raise RuntimeError(
f"ml_dtypes is not installed, cannot convert {dtype} array to numpy."
)
try:
dtype = getattr(ml_dtypes, dtype)
except AttributeError:
raise RuntimeError(f"ml_dtypes has no attribute '{dtype}', cannot convert array.")
np_arr = np.empty(shape, dtype=dtype)
assert np_arr.flags["C_CONTIGUOUS"]
data = np_arr.ctypes.data_as(ctypes.c_void_p)
# TODO(kathy): revisit and get a mirrored function of ffi::GetDataSize
# in Python to replace line below
nbytes = np_arr.size if dtype == "bool" else (np_arr.size * old_dtype.bits + 7) // 8
_ffi_api.TVMTensorCopyToBytes(self, data, nbytes)
if old_dtype == "int4" or old_dtype.startswith("float4_e2m1fn"):
length = np_arr.size
np_arr = np_arr.view("int8")
np_arr_ret = np.empty((length,), dtype="int8")
np_arr = np_arr.reshape((length,))
odd_index = np.bitwise_and(np_arr, 0x0F)
even_index = np.bitwise_and(np_arr >> 4, 0x0F)
np_arr_ret[1::2] = odd_index[0 : length // 2]
np_arr_ret[0::2] = even_index[0 : (length + 1) // 2]
return np_arr_ret.reshape(shape).view(dtype)
return np_arr
def copyto(self, target, mem_scope=None):
"""Copy array to target
Parameters
----------
target : Tensor
The target array to be copied, must have same shape as this array.
mem_scope : Optional[str]
The memory scope of the array.
"""
if isinstance(target, Tensor):
return self._copyto(target)
if isinstance(target, tvm_ffi.core.Device):
res = empty(self.shape, self.dtype, target, mem_scope)
return self._copyto(res)
raise ValueError(f"Unsupported target type {type(target)}")
def _copyto(self, target_nd):
"""Internal function that implements copy to target ndarray."""
_ffi_api.TVMTensorCopyFromTo(self, target_nd)
return target_nd
def _create_view(self, shape, dtype: str | None = None, relative_byte_offset: int = 0):
"""Create a view into an existing array.
The view shares the same allocation and datatype as the
existing array, but can have a different array shape. This is
useful for runtimes that support non-flat memory, where both
the physical shape of an allocation and the logical shape of
the tensor it represents may need to be independently
specified.
Warning: This function should not be used outside of low-level
manipulations, as it breaks non-aliasing assumptions made by
TVM. This function may also be removed/replaced in the
future.
Parameters
----------
shape: Union[tvm_ffi.Shape, Sequence[typing.SupportsInt]]
The shape of the view.
dtype: Optional[str]
The datatype of the view. If None (default), the view
will be the same data type as the current array.
relative_byte_offset: int
The location of the view, relative to the location of the current
array.
Note: While the `DLTensor.byte_offset` field of the returned view
is usually the same as `relative_byte_offset`, this is not
guaranteed. The `DLTensor.byte_offset` field is relative to the
start of the backing allocation, while the `relative_byte_offset`
is relative to the start of `self`.
"""
if not isinstance(shape, tvm_ffi.Shape):
shape = tvm_ffi.Shape([int(dim) for dim in shape])
if dtype is None:
dtype = self.dtype
return _ffi_api.TVMTensorCreateView(self, shape, dtype, relative_byte_offset)
def empty(shape, dtype="float32", device=None, mem_scope=None):
"""Create an empty array given shape and device
Parameters
----------
shape : Union[tvm_ffi.Shape, Sequence[typing.SupportsInt]]
The shape of the array.
dtype : type or str
The data type of the array.
device : Device
The device of the array.
mem_scope : Optional[str]
The memory scope of the array.
Returns
-------
arr : tvm.runtime.Tensor
The array tvm supported.
"""
device = device or cpu()
if not isinstance(shape, tvm_ffi.Shape):
shape = tvm_ffi.Shape([int(dim) for dim in shape])
dtype = tvm_ffi.dtype(dtype)
arr = _ffi_api.TVMTensorAllocWithScope(shape, dtype, device, mem_scope)
return arr
def tensor(arr, device=None, mem_scope=None):
"""Create an tensor from source arr.
Parameters
----------
arr : numpy.ndarray
The array to be copied from
device : Device, optional
The device to create the array
mem_scope : Optional[str]
The memory scope of the array
Returns
-------
ret : Tensor
The created array
"""
device = device or cpu()
if not isinstance(arr, np.ndarray | Tensor):
arr = np.asarray(arr)
return empty(arr.shape, arr.dtype, device, mem_scope).copyfrom(arr)
def cpu(dev_id=0):
"""Construct a CPU device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLCPU, dev_id)
def cuda(dev_id=0):
"""Construct a CUDA GPU device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLCUDA, dev_id)
def rocm(dev_id=0):
"""Construct a ROCM device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLROCM, dev_id)
def opencl(dev_id=0):
"""Construct a OpenCL device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLOpenCL, dev_id)
def metal(dev_id=0):
"""Construct a metal device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLMetal, dev_id)
def vpi(dev_id=0):
"""Construct a VPI simulated device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLVPI, dev_id)
def vulkan(dev_id=0):
"""Construct a Vulkan device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLVulkan, dev_id)
def ext_dev(dev_id=0):
"""Construct a extension device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
Note
----
This API is reserved for quick testing of new
device by plugin device API as ext_dev.
"""
return device(DLDeviceType.kDLExtDev, dev_id)
def hexagon(dev_id=0):
"""Construct a Hexagon device
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLHexagon, dev_id)
def webgpu(dev_id=0):
"""Construct a webgpu device.
Parameters
----------
dev_id : int, optional
The integer device id
Returns
-------
dev : Device
The created device
"""
return device(DLDeviceType.kDLWebGPU, dev_id)
# Register back to FFI
tvm_ffi.core._set_class_tensor(Tensor)