【发布时间】：2022-07-31 05:35:57
【问题描述】：
我是使用 GPU 进行数据操作的新手，并且一直在努力复制 cuDF 中的一些功能。例如，我想为数据集中的每个组获取一个众数值。在 Pandas 中，可以使用自定义函数轻松完成：
df = pd.DataFrame({\'group\': [1, 2, 2, 1, 3, 1, 2],
\'value\': [10, 10, 30, 20, 20, 10, 30]}
| group | value |
| ----- | ----- |
| 1 | 10 |
| 2 | 10 |
| 2 | 30 |
| 1 | 20 |
| 3 | 20 |
| 1 | 10 |
| 2 | 30 |
def get_mode(customer):
freq = {}
for category in customer:
freq[category] = freq.get(category, 0) + 1
key = max(freq, key=freq.get)
return [key, freq[key]]
df.groupby(\'group\').agg(get_mode)
| group | value |
| ----- | ----- |
| 1 | 10 |
| 2 | 30 |
| 3 | 20 |
但是，我似乎无法在 cuDF 中复制相同的功能。尽管似乎有一种方法可以做到这一点，我已经找到了一些例子，但它在我的情况下不起作用。例如，以下是我尝试用于 cuDF 的函数：
def get_mode(group, mode):
print(group)
freq = {}
for i in range(cuda.threadIdx.x, len(group), cuda.blockDim.x):
category = group[i]
freq[category] = freq.get(category, 0) + 1
mode = max(freq, key=freq.get)
max_freq = freq[mode]
df.groupby(\'group\').apply_grouped(get_mode, incols=[\'group\'],
outcols=dict((mode=np.float64))
有人可以帮我了解这里出了什么问题，以及如何解决吗？尝试运行上面的代码会引发以下错误（希望我设法将其置于剧透之下）：
错误代码TypingError: Failed in cuda mode pipeline (step: nopython frontend)
Failed in cuda mode pipeline (step: nopython frontend)
- Resolution failure for literal arguments:
No implementation of function Function(<function impl_get at 0x7fa8f0500710>) found for signature:
>>> impl_get(DictType[undefined,undefined]<iv={}>, int64, Literal[int](0))
There are 2 candidate implementations:
- Of which 1 did not match due to:
Overload in function \'impl_get\': File: numba/typed/dictobject.py: Line 710.
With argument(s): \'(DictType[undefined,undefined]<iv=None>, int64, int64)\':
Rejected as the implementation raised a specific error:
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
non-precise type DictType[undefined,undefined]<iv=None>
During: typing of argument at /opt/conda/lib/python3.7/site-packages/numba/typed/dictobject.py (719)
File \"../../opt/conda/lib/python3.7/site-packages/numba/typed/dictobject.py\", line 719:
def impl(dct, key, default=None):
castedkey = _cast(key, keyty)
^
raised from /opt/conda/lib/python3.7/site-packages/numba/core/typeinfer.py:1086
- Of which 1 did not match due to:
Overload in function \'impl_get\': File: numba/typed/dictobject.py: Line 710.
With argument(s): \'(DictType[undefined,undefined]<iv={}>, int64, Literal[int](0))\':
Rejected as the implementation raised a specific error:
TypingError: Failed in nopython mode pipeline (step: nopython frontend)
non-precise type DictType[undefined,undefined]<iv={}>
During: typing of argument at /opt/conda/lib/python3.7/site-packages/numba/typed/dictobject.py (719)
File \"../../opt/conda/lib/python3.7/site-packages/numba/typed/dictobject.py\", line 719:
def impl(dct, key, default=None):
castedkey = _cast(key, keyty)
During: resolving callee type: BoundFunction((<class \'numba.core.types.containers.DictType\'>, \'get\') for DictType[undefined,undefined]<iv={}>)
During: typing of call at /tmp/ipykernel_33/2595976848.py (6)
File \"../../tmp/ipykernel_33/2595976848.py\", line 6:
<source missing, REPL/exec in use?>
During: resolving callee type: type(<numba.cuda.compiler.Dispatcher object at 0x7fa8afe49520>)
During: typing of call at <string> (10)
File \"<string>\", line 10:
<source missing, REPL/exec in use?>