exercises
Numpy
exercises 9.1
题目:
源代码:
from numpy import * import numpy as np def fun(A, B, v, I): print("A + A = ") C = A + A print(C) print("AAT = ") D = A * A.T print(D) print("ATA = ") E = A.T * A print(E) print("AB = ") F = A * B print(F) print("A(B-vI) = ") J = I*v B = B - J A = A*B print(A) I = mat(eye(500, 200, dtype = int)) A = mat(random.randint(10, size = (200, 500))) B = mat(random.randint(10, size = (500, 200))) v = int(input("Please enter v = ")) print(fun(A, B, v, I))
完成结果:
exercises 9.2
题目:
源代码:
from numpy import * import numpy as np def fun(B, b): print("x = ") x = B/b print(x) B = mat(random.randint(1, 10, size = (500, 200))) b = mat(random.randint(1, 10, size = (500, 1))) fun(B, b)
完成结果:
exercise 9.3
题目:
源代码:
from numpy import * import numpy as np def fun(A, B): print("||A||1 = ") print(np.linalg.norm(A, ord=1)) print("||A||2 = ") print(np.linalg.norm(A, ord=2)) print("||B|| = ") print(np.linalg.norm(B, ord=np.inf)) print("the largest singular value of B is ") print(B.max()) print("the smallest singular value of B is ") print(B.min()) A = mat(random.randint(1, 10, size = (200, 500))) B = mat(random.randint(1, 10, size = (500, 200))) fun(A, B)
完成结果:
exercises 9.4
题目:
源代码:
from numpy import * import numpy as np def fun(Z, A, B): print("the largest eigenvalue is ") print(np.argsort(A)[0]) print("the largest corresponding eigenvector is ") print(np.argsort(B)[0]) Z = np.random.random_integers(100, size = (200, 200)) A,B = np.linalg.eig(Z) fun(Z, A, B)
完成结果:
exercises 9.5
题目:
源代码:
from numpy import * import numpy as np def fun(C, p): for i in range(0, 200): for j in range(0, 200): if np.random.rand() < p: C[i][j] = 1 print("the largest singular vale is ") x = np.linalg.svd(C) print(x[0]) C = np.zeros([200,200]) p = float(input("p = ")) fun(C, p)
完成结果:
exercise 9.6
题目:
源代码:
def fun(z, A, n): le = abs(A[0]-z) zz = A[0] for i in range(0, n): if abs(A[i]-z) < le: le = abs(A[i]-z) zz = A[i] print(zz) z = int(input("z = ")) n = int(input("n = ")) A = [] for i in range(0, n): data = int(input()) A.append(data) fun(z, A, n)
完成结果: