import numpy as np
b = np.array([[1., 2.], [3., 4.]])
b[0, 0] = 0
b[1, 1] = 0
a = np.sum(b)
print(a)

import numpy as np
a = np.array((100, 101, 102, 103))
b = np.ones_like(a)
print(np.sum(b))

import numpy as np
a = np.array((100, 101, 102, 103))
b = np.zeros_like(a)
print(np.sum(b))

import numpy as np
a = np.arange(1, 2, 1)
b = np.linspace(1, 2, 1, dtype=int)
print(a + b)

import numpy as np
x, dx = np.linspace(0, 8, 9, retstep=True)
print(dx)

import numpy as np
x = np.linspace(0, 5, 5, endpoint=False)
y = np.linspace(0, 5, 5, endpoint=True)
print(x.size - y.size)

def f(i, j):
    return i * j

x = np.fromfunction(f, (3, 3), dtype=int)
y = np.sum(x)
print(y)

import numpy as np
x = np.fromfunction(lambda i, j: 2 * i * j, (3, 3), dtype=int)
y = np.sum(x[1])
print(y)

import numpy as np
a = np.array(((1, 0, 1), (0, 1, 0)))
print(a.shape)