الدوال الشاملة (ufuncs)

import numpy as np

a = np.array([1.0, 4.0, 9.0, 16.0])
print(np.sqrt(a))  # [1. 2. 3. 4.]
# Equivalent Python loop would be hundreds of times slower

import numpy as np

a = np.array([0.0, 1.0, 2.0, 3.0])
print(np.exp(a))         # [1.    2.718 7.389 20.086]
print(np.log(np.exp(a))) # [0. 1. 2. 3.]
print(np.log2(np.array([1, 2, 4, 8])))  # [0. 1. 2. 3.]

import numpy as np

angles = np.array([0, 30, 60, 90])
rad = np.deg2rad(angles)
print(np.sin(rad).round(4))  # [0.     0.5    0.866  1.   ]
print(np.cos(rad).round(4))  # [1.     0.866  0.5    0.   ]

import numpy as np

a = np.array([-2.7, 0.4, 1.5, 3.9])
print(np.abs(a))     # [2.7 0.4 1.5 3.9]
print(np.floor(a))   # [-3.  0.  1.  3.]
print(np.ceil(a))    # [-2.  1.  2.  4.]
print(np.round(a))   # [-3.  0.  2.  4.]

import numpy as np

a = np.array([-3, 1, 5, -2, 4])
b = np.array([0, 0, 3, 3, 3])

print(np.maximum(a, b))  # [0 1 5 3 4]
print(np.minimum(a, b))  # [-3  0  3 -2  3]

# ReLU
print(np.maximum(a, 0))  # [0 1 5 0 4]

import numpy as np

a = np.array([0.1, 0.5, -0.2, 1.3, 0.9])
clipped = np.clip(a, 0.0, 1.0)
print(clipped)  # [0.1 0.5 0.  1.  0.9]

import numpy as np

m = np.array([[1.0, 4.0], [9.0, 16.0]])
print(np.sqrt(m))
# [[1. 2.]
#  [3. 4.]]

import numpy as np

a = np.array([1.0, 4.0, 9.0])
result = np.empty(3)
np.sqrt(a, out=result)  # write directly into result
print(result)  # [1. 2. 3.]

import numpy as np

a = np.array([1, 2, 3, 4, 5])
print(np.add.reduce(a))       # 15
print(np.add.accumulate(a))   # [ 1  3  6 10 15]
print(np.multiply.reduce(a))  # 120

import numpy as np

def clamp_positive(x):
    return x if x > 0 else 0.0

vfunc = np.frompyfunc(clamp_positive, 1, 1)
a = np.array([-2, 3, -1, 5])
print(vfunc(a))  # [0.0 3 0.0 5]  (object dtype)

import numpy as np
import time

a = np.random.rand(1_000_000)

start = time.perf_counter()
np.sqrt(a)
print('ufunc:', round(time.perf_counter() - start, 4), 's')

start = time.perf_counter()
[x ** 0.5 for x in a]
print('loop:', round(time.perf_counter() - start, 4), 's')