# coding: utf-8
# Here your code !

# 疎行列とベクトルの積

import numpy as np
from scipy.sparse import lil_matrix, csr_matrix

def csr_SpMV(A, b):
    return A.dot(b)

#全体行列の大きさ
n = 10  # 10×10 行列

A = lil_matrix( (n, n) )

for i in range(1, n - 1):
    for j in range(2):
        A[i, i + j] = i + j

A[0, 0] = 1

A[n - 1, n - 1] = n - 1

A = A.tocsr()

# 密行列に変換して内容確認
print(A.todense())
print(A.dot(A).todense())