我正在开发一个 jitclass,其中方法之一可以接受
int
、float
或 numpy.ndarray
的输入参数。我需要能够确定参数是数组还是其他两种类型中的任何一种。我尝试过使用 isinstance
,如下面的 interp
方法所示:
spec = [('x', float64[:]),
('y', float64[:])]
@jitclass(spec)
class Lookup:
def __init__(self, x, y):
self.x = x
self.y = y
def interp(self, x0):
if isinstance(x0, (float, int)):
result = self._interpolate(x0)
elif isinstance(x0, np.ndarray):
result = np.zeros(x0.size)
for i in range(x0.size):
result[i] = self._interpolate(x0[i])
else:
raise TypeError("`interp` method can only accept types of float, int, or ndarray.")
return result
def _interpolate(self, x0):
x = self.x
y = self.y
if x0 < x[0]:
return y[0]
elif x0 > x[-1]:
return y[-1]
else:
for i in range(len(x) - 1):
if x[i] <= x0 <= x[i + 1]:
x1, x2 = x[i], x[i + 1]
y1, y2 = y[i], y[i + 1]
return y1 + (y2 - y1) / (x2 - x1) * (x0 - x1)
但是我收到以下错误:
numba.errors.TypingError: Failed at nopython (nopython frontend)
Failed at nopython (nopython frontend)
Untyped global name 'isinstance': cannot determine Numba type of <class 'builtin_function_or_method'>
File "Lookups.py", line 17
[1] During: resolving callee type: BoundFunction((<class 'numba.types.misc.ClassInstanceType'>, 'interp') for instance.jitclass.Lookup#2167664ca28<x:array(float64, 1d, A),y:array(float64, 1d, A)>)
[2] During: typing of call at <string> (3)
在使用 jitclasses 或 nopython 模式时,有没有办法确定输入参数是否属于某种类型?
我应该之前提到过这一点,但使用内置的
type
似乎也不起作用。例如,如果我将 interp
方法替换为:
def interp(self, x0):
if type(x0) == float or type(x0) == int:
result = self._interpolate(x0)
elif type(x0) == np.ndarray:
result = np.zeros(x0.size)
for i in range(x0.size):
result[i] = self._interpolate(x0[i])
else:
raise TypeError("`interp` method can only accept types of float, int, or ndarray.")
return result
我收到以下错误:
numba.errors.TypingError: Failed at nopython (nopython frontend)
Failed at nopython (nopython frontend)
Invalid usage of == with parameters (class(int64), Function(<class 'float'>))
我认为这是指当我做类似
float
的事情时,python int64
和 numba lookup_object.interp(370)
的比较。
如果您需要确定和比较 numba
jitclass
或 nopython jit
函数内的类型,那么您就不走运了,因为根本不支持 isinstance
并且 type
仅支持少数数字类型,并且命名元组(请注意,这只是返回类型 - 它不适合比较 - 因为 ==
没有为 numba 函数内的类实现)。
从 Numba 0.35 开始,唯一支持的内置函数是(来源:numba 文档):
支持以下内置功能:
abs() bool complex divmod() enumerate() float int: only the one-argument form iter(): only the one-argument form len() min() max() next(): only the one-argument form print(): only numbers and strings; no file or sep argument range: semantics are similar to those of Python 3 even in Python 2: a range object is returned instead of an array of values. round() sorted(): the key argument is not supported type(): only the one-argument form, and only on some types (e.g. numbers and named tuples) zip()
我的建议:使用普通的 Python 类并确定其中的类型,然后相应地转发到
numba.njit
ted 函数:
import numba as nb
import numpy as np
@nb.njit
def _interpolate_one(x, y, x0):
if x0 < x[0]:
return y[0]
elif x0 > x[-1]:
return y[-1]
else:
for i in range(len(x) - 1):
if x[i] <= x0 <= x[i + 1]:
x1, x2 = x[i], x[i + 1]
y1, y2 = y[i], y[i + 1]
return y1 + (y2 - y1) / (x2 - x1) * (x0 - x1)
@nb.njit
def _interpolate_many(x, y, x0):
result = np.zeros(x0.size, dtype=np.float_)
for i in range(x0.size):
result[i] = _interpolate_one(x, y, x0[i])
return result
class Lookup:
def __init__(self, x, y):
self.x = x
self.y = y
def interp(self, x0):
if isinstance(x0, (float, int)):
result = _interpolate_one(self.x, self.y, x0)
elif isinstance(x0, np.ndarray):
result = _interpolate_many(self.x, self.y, x0)
else:
raise TypeError("`interp` method can only accept types of float, int, or ndarray.")
return result
从 numba 0.52 开始,支持
np.shape()
。因此,如果您只想区分 np.ndarray
和标量,则可以使用以下方法:
@njit
def test(a):
if len(np.shape(a)) > 0:
return 'np.ndarray'
else:
return 'not an array'
>>> test(1)
'not an array'
>>> test(np.array([1,2,3]))
'np.ndarray'
也许有点晚了,但你可以尝试使用
objmode
:
@njit
def isarray(obj):
with objmode(isarray="boolean"):
isarray = isinstance(obj, np.ndarray)
return isarray
然后使用
isarray(x0)
代替 isinstance(x0, np.ndarray)
。
这是根据参数类型替换所需函数实现的示例。
在 numba 0.57.1 上测试
import numba as nb
import numba.experimental as nbexp
import numba.extending as nbex
from numba import types as nbt
@nbexp.jitclass([ ('_x', nbt.float32),
('_y', nbt.float32), ])
class Vec2:
def __init__(self, x : float, y : float):
self._x = x
self._y = y
@property
def x(self) -> float: return self._x
@property
def y(self) -> float: return self._y
def __mul__(self, other): return Vec2(0,0) # overloaded
# Overload implementations
def Vec2__mul__Vec2(self, other): return Vec2(self._x*other._x, self._y*other._y)
def Vec2__mul__number(self, other): return Vec2(self._x*float(other), self._y*float(other))
# Overloaders
@nbex.overload_method(nbt.misc.ClassInstanceType, "__mul__")
def over_Vec2__mul__(self, other):
if self is Vec2.class_type.instance_type:
if other is Vec2.class_type.instance_type: return Vec2__mul__Vec2
if other in nbt.number_domain: return Vec2__mul__number
# Tests
@nb.njit(nogil=True)
def run_test1():
return Vec2(1,1) * 2
@nb.njit(nogil=True)
def run_test2():
return Vec2(1,1) * Vec2(3,3)
print( run_test1().x ) # outputs 2.0
print( run_test2().x ) # outputs 3.0
使用
type()
?
blah = []
if type(blah) is list:
print "Is a list"
blah = 5
if type(blah) is int:
print "we have an int"
即:
>>> blah = 5
>>> type(blah)
<type 'int'>
>>>