题目
解析
# 2.1
x = matrix(c(1,2,3),byrow=F)
y = matrix(c(4,5,6),byrow=F)
# (1)
# A * B 对应元素相乘
# A %*% B 内积
# A %o% B 外积
e = matrix(rep(1,3),byrow=F)
z = 2*x + y + e
z
# (2)
x %*% y
# (3)
x %o% y
# 2.2
A = matrix(1:20,nrow=4,ncol=5,byrow=F)
B = matrix(1:20,nrow=4,ncol=5,byrow=T)
# (1)
C = A + B
# (2)
D = A %*% B
# (3)
E = A * B
# (4)
F = A[1:3,1:3]
# (5)
G = matrix(0,nrow=4,ncol=4) # 初始化
for (i in 1:5) {
G[,i] = B[,i]
if (i >= 3) G[,i] = B[,i+1]
}
# 2.3
x = rep(1:4,c(5,3,4,2))
# 2.4
n = 5
H = matrix(0,nrow=n,ncol=n) # 初始化
for (i in 1