Game of Life comments for Mazdaika

GOL_MazdaikaComments.R

# Author: Mazdaika
###############################################################################


## should be col*row, not col+row

# create matrix - initial life situation
crmtx <- function(col=5, row=5, st=0.4){
	x <- matrix(rbinom(col+row,1, st), ncol=col, nrow=row)
	return(x)
}

# count neighbours for cells
neighbours <- function(mx) {
	mt_c <- neighbours_c(mx)
	mt_d <- neighbours_d(mx)
	mt <- mt_c + mt_d
	return(mt)
}

## 1) looks like you have a dead border implementation. No big deal, just be sure to state so
## certain neat formations, like gliders, etc, will have limited lifespans
## to have wrapped borders, instead of e.g. rbind(mx1[-1,],0) you could do rbind(mx1[-1,],mx1[,ncol(mx1)])
## 2) you could eliminate calls to neighbours_c() and neighbours_d() by putting it all 
## into neighbors()

# count neighbours in cross area
neighbours_c <- function(mx1){
	mt11 <- rbind(mx1[-1,],0) + rbind(0, mx1[-nrow(mx1),])
	mt22 <- cbind(mx1[,-1],0) + cbind(0, mx1[,-ncol(mx1)])
	mt1 <- mt11 + mt22
	return(mt1)
}

# count neighbours in diag area
neighbours_d <- function(mx){
	mx_up <- rbind(mx[-1,],0)
	mx_up <- cbind(mx_up[,-1],0) + cbind(0, mx_up[,-ncol(mx_up)])
	mx_dw <- rbind(0,mx[-nrow(mx),])
	mx_dw <- cbind(mx_dw[,-1],0) + cbind(0, mx_dw[,-ncol(mx_dw)])
	mt22 <- mx_up + mx_dw
	return(mt22)
}

## 1) switch has a special meaning in R, Like TRUE or FALSE.
## You should name the function something else
## 2) looks like you iterate down rows: really there's no need to iterate at all
## see if you can figure out how to eliminate the loop

# count next period of life
switch <- function(mxs,mts) {
	mout <- matrix(0, ncol= ncol(mxs), nrow=nrow(mxs))
	for(i in 1:nrow(mxs))
	{
		a <- mxs[i,]
		a <- ifelse((a==1 & (mts[i,] > 3 | mts[i,] < 2)) | (a==0 & mts[i,] < 3) ,0,1)
		mout[i,] <- a
	}
	return(mout)
}

## recall that image() transposes the matrix, so you can do t(mx)- really makes no diff
## though since the system evolves the same either way

# run one iteration of life
iterate <- function(iters, rows, cols, prob, clrs, slp) {
	
	mx <- crmtx(rows,cols, prob)
	for (i in 1:iters)
	{
		Sys.sleep(slp)
		mt <- neighbours(mx)
		mx <- switch(mx,mt)
		image(mx, axes = FALSE, col = clrs)
	}
}

# variables
sleep <- 0.1
rows <- 100
coloumns <- 100
probability <- 0.4
colours <- c("#0f0f0f", "#ffffff")
iterations <- 100

#start
iterate(iterations, rows, coloumns, probability, colours, sleep)