【Numpy】练习题

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最新推荐文章于 2025-05-29 15:26:53 发布 · 540 阅读

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Exercise 9.1: Matrix operations

题目描述

Calculate A + A, AA^T, A^TA and AB. Write a function that computes A(B -tI) for any t.

输入样例

输出样例

A + A = [[-0.59334828  0.8884575  -1.36523816 ... -2.02030659  0.19453275
   2.11587215]
 [-2.81791186 -2.88267176 -1.03896815 ...  0.50513996  1.49173622
  -0.33268223]
 [ 1.81893223 -0.97778773 -0.24765626 ... -0.14222241  1.10786192
  -4.35427287]
 ...
 [ 2.58180949  0.43558676  0.72247307 ... -1.4871005   0.04631172
  -0.59709626]
 [ 1.5098593  -1.27361792  2.5884521  ...  1.89708659  0.98811815
   0.28697544]
 [-7.64837192 -0.14700114 -1.58280627 ...  2.32408483  2.58086481
  -2.06438574]]
A * A^T = [[470.44338692  42.29280712  17.10223612 ...  18.91100284  15.67769139
   40.75185721]
 [ 42.29280712 475.70038961 -11.58347091 ... -15.97459961  16.07904308
  -11.8156372 ]
 [ 17.10223612 -11.58347091 471.39535028 ...  -3.54325763 -22.74446501
    5.16384204]
 ...
 [ 18.91100284 -15.97459961  -3.54325763 ... 458.76332228  23.34234596
   -1.45594504]
 [ 15.67769139  16.07904308 -22.74446501 ...  23.34234596 472.47156727
  -13.31998639]
 [ 40.75185721 -11.8156372    5.16384204 ...  -1.45594504 -13.31998639
  511.43900327]]
A^T * A = [[232.80738856   7.95941402  15.37981253 ... -14.05881828 -20.71737172
  -13.49575832]
 [  7.95941402 186.35319519  20.66773885 ...   3.39549772 -10.86798494
   10.8023167 ]
 [ 15.37981253  20.66773885 200.55277055 ...  -8.24671455 -23.38532638
    3.60540781]
 ...
 [-14.05881828   3.39549772  -8.24671455 ... 204.24581984 -15.25325464
   -0.83971902]
 [-20.71737172 -10.86798494 -23.38532638 ... -15.25325464 191.8058579
   -4.18234635]
 [-13.49575832  10.8023167    3.60540781 ...  -0.83971902  -4.18234635
  200.11400152]]
A * B = [[-104.11890528 -127.50165662  -74.0060889  ...  -73.41391463
   -27.45200506  -97.81103017]
 [  17.43003568  132.62518782   92.59608437 ...   57.63015635
   123.20641659   30.82112076]
 [ 173.68506942  176.05025446  117.74589784 ...  189.7801047
   127.43363064  118.65265685]
 ...
 [-190.80779557  -75.98950803  -15.5155604  ... -179.06148314
  -154.89361858  -84.96796462]
 [  -3.34434955 -124.00123772  -45.13904847 ... -135.10616698
   -87.78819411  -75.75593386]
 [ -15.47863655  -33.75863698   59.53654699 ...  106.40775681
    57.62160209  -60.303528  ]]
Please enter t: 
3
A * (B - tI) = [[-103.22888286 -128.83434287  -71.95823165 ...  -70.38345474
   -27.74380419 -100.98483839]
 [  21.65690347  136.94919546   94.1545366  ...   56.8724464
   120.96881226   31.32014411]
 [ 170.95667108  177.51693606  118.11738223 ...  189.99343831
   125.77183776  125.18406616]
 ...
 [-194.6805098   -76.64288816  -16.59927001 ... -176.83083239
  -154.96308616  -84.07232023]
 [  -5.6091385  -122.09081083  -49.02172662 ... -137.95179686
   -89.27037133  -76.18639703]
 [  -4.00607867  -33.53813526   61.9107564  ...  102.92162957
    53.75030488  -57.20694939]]

代码展示

import numpy as np
from scipy.linalg import toeplitz

A = np.mat(np.random.randn(200, 500))
B = np.mat(toeplitz([np.random.randint(0,10) for i in range(500)]))

print("A + A = ",end="")
print(A + A)

print("A * A^T = ",end="")
print(A * (A.T))

print("A^T * A = ",end="")
print(A.T * A)

print("A * B = ",end="")
print(A * B)

t = (float)(input("Please enter t: \n"))
C = B
for i in range(500