[R] Function completely locks up my computer if the input is too big

[Benjamin Caldwell]

Dear r-help,


Somewhere in my innocuous function to rotate an object in Cartesian space
I've created a monster that completely locks up my computer (requires a
hard reset every time). I don't know if this is useful description to
anyone - the mouse still responds, but not the keyboard and not windows
explorer.

The script only does this when the input matrix is large, and so my initial
runs didn't catch it as I used a smaller matrix to speed up the test runs.
When I tried an input matrix with a number of dimensions in the same order
of magnitude as the data I want to read in, R and my computer choked. This
was a surprise for me, as I've always been able to break execution in the
past or do other tasks. So i tried it again, and still no dice.

Now I need the function to work as subsequent functions/functionality are
dependent, and I can't see anything on the face of it that would likely
cause the issue.

Any insight on why this happens in general or specifically in my case are
appreciated. Running R 15.2, Platform: x86_64-w64-mingw32/x64 (64-bit) on a
windows 7 machine with 4 mb RAM. In the meantime I suppose I'll write a
loop to do this function piece-wise for larger data and see if that helps.

Script is attached and appended below.

Thanks

Ben Caldwell



#compass to polar coordinates

compass2polar <- function(x) {-x+90}



#degrees (polar) to radians

Deg2Rad <- function(x) {(x*pi)/180}



# radians to degrees

Rad2Deg <- function (rad) (rad/pi)*180



# polar to cartesian coordinates - assumes degrees those from a compass.
output is a list, x & y of equal length

Pol2Car <- function(distance,deg) {


rad <- Deg2Rad(compass2polar(deg))

rad <- rep(rad, length(distance))


x <- ifelse(is.na(distance), NA, distance * cos(rad))

y <- ifelse(is.na(distance), NA, distance * sin(rad))


x<-round(x,2)

y<-round(y,2)


cartes<- list(x,y)

name<-c('x','y')

names(cartes)<-name

cartes

}





#rotate an object, with assumed origin at 0,0, in any number of degrees

rotate <- function(x,y,tilt){ 8


d2 <- x^2+y^2

rotate.dis<-sqrt(d2)

or.rad <- atan(x/y)

or.deg <- Rad2Deg(or.rad)


n <- length(or.deg)

for(i in 1:n){

if(is.na(or.deg[i])==TRUE) {or.deg[i] <- 0}

}

# browser()

tilt.in <- tilt + or.deg


xy<-Pol2Car (distance=rotate.dis, deg=tilt.in)

 # if(abs(tilt) >= 0) {

 # shift.frame <- cbind(xy$x, xy$y)

# shift.frame.val <- shift.frame[shift.frame[,2]==min(shift.frame[,2]),]

# shift.x<- shift.frame.val[1] * -1

# shift.y<- shift.frame.val[2] * -1

# x<-xy$x + shift.x

# y<-xy$y + shift.y

# }

# name <- c('x', 'y')

# xy<-list(x,y)

# names(xy)<-name

 xy

}


x <- seq(0,5, .5)

y <- seq(0,5, .5)

z <- seq(0,5, .5)

dquad<-expand.grid(x,y,z)

name<-c("y","x","z")

names(dquad)<-name


plot(dquad$x, dquad$y, xlim=c(-25,25), ylim=c(-25,25))


#this works fine

rotated<-rotate(dquad$x, dquad$y, 45)



points(rotated$x, rotated$y, col='green')


# profiling of both time and memory

Rprof(“myFunction.out”, memory.profiling=T)

y <- myFunction(x)

Rprof(NULL)

summaryRprof(“myFunction.out”, memory=”both”)



#############

x <- seq(0,5, .1)

y <- seq(0,5, .1)

z <- seq(0,5, .1)

dquad<-expand.grid(x,y,z)

name<-c("y","x","z")

names(dquad)<-name

# running the below locks up my machine (commented out to avoid accidental
run)

# rotated<-rotate(dquad$x, dquad$y, 45)