1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
require(compiler)
assert = function(bool) {
if (!bool) stop('Assertion failed')
}
timeit = function(name, f, ..., times=5) {
tmin = Inf
f = cmpfun(f)
for (t in 1:times) {
t = system.time(f(...))["elapsed"]
if (t < tmin) tmin = t
}
cat(sprintf("r,%s,%.8f\n", name, tmin*1000))
}
## fib ##
fib = function(n) {
if (n < 2) {
return(n)
} else {
return(fib(n-1) + fib(n-2))
}
}
assert(fib(20) == 6765)
timeit("fib", fib, 20)
## parse_int ##
parseintperf = function(t) {
for (i in 1:t) {
# R doesn't support uint32 values
n = floor(2^31-1*runif(1))
s = sprintf("0x%x", n)
m = as.numeric(s)
assert(m == n)
}
}
timeit("parse_int", parseintperf, 1000)
## quicksort ##
qsort = function(a) {
qsort_kernel = function(lo, hi) {
i = lo
j = hi
while (i < hi) {
pivot = a[floor((lo+hi)/2)]
while (i <= j) {
while (a[i] < pivot) i = i + 1
while (a[j] > pivot) j = j - 1
if (i <= j) {
t = a[i]
a[i] <<- a[j]
a[j] <<- t
i = i + 1;
j = j - 1;
}
}
if (lo < j) qsort_kernel(lo, j)
lo = i
j = hi
}
}
qsort_kernel(1, length(a))
return(a)
}
sortperf = function(n) {
v = runif(n)
return(qsort(v))
}
assert(!is.unsorted(sortperf(5000)))
timeit('quicksort', sortperf, 5000)
## mandel ##
mandel = function(z) {
c = z
maxiter = 80
for (n in 1:maxiter) {
if (Mod(z) > 2) return(n-1)
z = z^2+c
}
return(maxiter)
}
mandelperf = function() {
re = seq(-2,0.5,.1)
im = seq(-1,1,.1)
M = matrix(0.0,nrow=length(re),ncol=length(im))
count = 1
for (r in re) {
for (i in im) {
M[count] = mandel(complex(real=r,imag=i))
count = count + 1
}
}
return(M)
}
assert(sum(mandelperf()) == 14791)
timeit("mandel", mandelperf)
## pi_sum ##
pisum = function() {
t = 0.0
for (j in 1:500) {
t = 0.0
for (k in 1:10000) {
t = t + 1.0/(k*k)
}
}
return(t)
}
assert(abs(pisum()-1.644834071848065) < 1e-12);
timeit("pi_sum", pisum, times=1)
## pi_sum_vec ##
pisumvec = function() {
r = 1:10000
return(replicate(500, sum(1/((r)^2)))[1])
}
#assert(abs(pisumvec()-1.644834071848065) < 1e-12);
#timeit("pi_sum_vec", pisumvec, times=10)
## rand_mat_stat ##
randmatstat = function(t) {
n = 5
v = matrix(0, nrow=t)
w = matrix(0, nrow=t)
for (i in 1:t) {
a = matrix(rnorm(n*n), ncol=n, nrow=n)
b = matrix(rnorm(n*n), ncol=n, nrow=n)
c = matrix(rnorm(n*n), ncol=n, nrow=n)
d = matrix(rnorm(n*n), ncol=n, nrow=n)
P = cbind(a,b,c,d)
Q = rbind(cbind(a,b),cbind(c,d))
v[i] = sum(diag((t(P)%*%P)^4))
w[i] = sum(diag((t(Q)%*%Q)^4))
}
s1 = apply(v,2,sd)/mean(v)
s2 = apply(w,2,sd)/mean(w)
return(c(s1,s2))
}
timeit("rand_mat_stat", randmatstat, 1000)
## rand_mat_mul ##
randmatmul = function(n) {
A = matrix(runif(n*n), ncol=n, nrow=n)
B = matrix(runif(n*n), ncol=n, nrow=n)
return(A %*% B)
}
assert(randmatmul(1000)[1] >= 0)
timeit("rand_mat_mul", randmatmul, 1000)
|
