[R] Confused by code?

[Bazman76]

Thanks Rui Barrudas and Peter Alspach,

I understand better now:

x<-matrix(c(1,0,0,0,2,0,0,0,2),nrow=3) 
 y<-matrix(c(7,8,9,1,5,10,1,1,0),nrow=3) 
 z<-matrix(c(0,1,0,0,0,0,6,0,0),nrow=3) 
 x[z]<-y[z] 
 viewData(x)

produces an x matrix 

7   0   0
0   2   0
0   10 2

which makes sense the first element of y 7 is inserted into z in slot x[1] 
and the and 6th element of y 10 is slotted into the x[6]. 


However the original code runs like this:

mI<- mRU(de.d, de.nP)>de.CR
mPV[mI]<mP[mI]

where mPv and MP are both (de.d, de.nP) matrices.

and

mRU<-function(m,n){
             return(array(runif(m*n), dim=c(m,n)))
}

i.e. it returns an array of m*n random numbers uniformly distributed between
0 and 1.

de.CR is a fixed value say 0.8.

So mI<- mRU(de.d, de.NP)>de.CR returns a de.d*de.nP array where each
element is 1 is its more than 0.8 and zero otherwise.

So in this case element mPv[1] will be repeatedly filled with the value of
mP[1] and all other elements will remain unaffected?

Is this correct?

If so I am still confused as this is not what I thought was supposed to by
happening but I know that the code overall does its job correctly?



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