# SEC: random numbers
N = 10000
# N = 1000
random.data = rnorm(N, mean=0, sd=1)
hist(random.data, nclass = 50, col = "navy", xlab = "Data",
probability = T, main = "Histogram of Random Data")
# density of generated data
dens = density(random.data)
lines(dens, col = "orange", lwd = 4)
# theoretical density
x = seq(-4,4,0.1)
true.norm = dnorm(x, mean = 0, sd = 1)
lines(x,true.norm, col = "green", lty = 3, lwd = 4)
legend("topleft",c("empirical", "theoretical"), lty = c(1,3),
col = c('orange','green'),lwd=4)
# SEC: law of large numbers
# simplest version
six.counter=0; N = 1000
for (i_loop in 1:N) {
die<-sample(1:6,1)
if (die==6) {six.counter=six.counter+1}
}
six.counter/N
# simpler version
N=1000; six.counter=rep(0,N);
for (i_loop in 1:N) {
die<-sample(1:6,1)
if (die==6) {six.counter[i_loop]=1}
}
plot(1:N,cumsum(six.counter)/(1:1000),type='l',ylim=c(0,1),lwd=2)
abline(h=1/6,lwd=2,col='red')
# simple version
N = 1000
die.all <- sample(1:6,N,replace=T)
six.index <- die.all==6
par(mfrow = c(2,1))
par(oma=c(2,2,0,0),mar=c(4,4,1,1),mfrow=c(2,1))
plot(1:N, die.all, pch=20, col = 'red', ylim = c(0,7),
ylab = "Result", xlab = "trial")
plot(1:N,cumsum(six.index)/(1:1000), type='l', ylim=c(0,1), lwd=2,
ylab = "P(die = 6)", xlab = "trial")
abline(h=1/6,lwd=2,col='red')
# CLT
par(mfrow=c(1,1))
N=10
nRep=10000
dat<-matrix(runif(N*nRep),nrow=N)
means<-colMeans(dat)
hist(means,nclass=50,probability=T)
dens<-density(means);lines(dens,col='skyblue',lwd=3)
xs=seq(-0,1,0.01)
theo.dens<-dnorm(xs,mean=0.5,sd=sqrt((1/12)/N))
lines(xs,theo.dens,col='orange',lwd=3,lty=2)
# GCD
# script version
r=-99;v1=1633;v2=355
while (r!=0){
r=v1%%v2
print(paste('v1 =',v1,', v2 = ',v2,',remainder = ',r))
v1=v2
v2=r
}
# function version
GCD<-function(v1,v2){
real.v1=max(c(v1,v2))
real.v2=min(c(v1,v2))
repeat{
r=real.v1%%real.v2;real.v1=real.v2;real.v2=r
if (r==0){
print(paste('GCD is',real.v1));
return(real.v1);
break}
}
}
GCD(1633,355)
# digit conversion
# binary to dec
bin2dec=function(bin) {
ones=which(rev(bin)==1)-1
dec=sum(2^ones)
return(dec)
}
# dec 2 bin - script
num=150;bin=c()
while(num!=0) {
rem=num%%2;
num=num%/%2
bin=print(c(rem,bin))
}
# dec 2 bin - function
dec2bin<-function(num, digits=8) {
bin=c()
if (num==0){
bin=0
} else {
while(num!=0){
rem=num%%2
num=num%/%2
bin=c(rem,bin)
}
}
if (length(bin)
Related