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I have a 7000 X 7000 matrix in R. For example purpose I will use a smaller matrix as following:-
a <- matrix(c(0:-9, 1:-8, 2:-7, 3:-6, 4:-5, 5:-4, 6:-3, 7:-2, 8:-1, 9:0),
byrow = TRUE, ncol = 10, nrow = 10)
I want to create a new matrix which has values equal to 1 where the absolute values in matrix a are between the closed interval of 2 and 5. And rest all other values equal to zero.
This would make the following matrix:-
b <- matrix(c(0,0,1,1,1,1,0,0,0,0
0,0,0,1,1,1,1,0,0,0
1,0,0,0,1,1,1,1,0,0
1,1,0,0,0,1,1,1,1,0
1,1,1,0,0,0,1,1,1,1
1,1,1,1,0,0,0,1,1,1
0,1,1,1,1,0,0,0,1,1
0,0,1,1,1,1,0,0,0,1
0,0,0,1,1,1,1,0,0,0
0,0,0,0,1,1,1,1,0,0),
byrow = TRUE, ncol = 10, nrow = 10)
I can do this using for loop, but I just want to know if there is a much better and effcient solution to do this.
Thanks in advance.
You can just write down the comparison. It gives you a logical matrix and you can then use unary + to turn the result into an integer matrix.
+(abs(a) >= 2 & abs(a) <= 5)
# [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
# [1,] 0 0 1 1 1 1 0 0 0 0
# [2,] 0 0 0 1 1 1 1 0 0 0
# [3,] 1 0 0 0 1 1 1 1 0 0
# [4,] 1 1 0 0 0 1 1 1 1 0
# [5,] 1 1 1 0 0 0 1 1 1 1
# [6,] 1 1 1 1 0 0 0 1 1 1
# [7,] 0 1 1 1 1 0 0 0 1 1
# [8,] 0 0 1 1 1 1 0 0 0 1
# [9,] 0 0 0 1 1 1 1 0 0 0
#[10,] 0 0 0 0 1 1 1 1 0 0
Perhaps you can try
> +((abs(a) - 2) * (abs(a) - 5) <= 0)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 0 0 1 1 1 1 0 0 0 0
[2,] 0 0 0 1 1 1 1 0 0 0
[3,] 1 0 0 0 1 1 1 1 0 0
[4,] 1 1 0 0 0 1 1 1 1 0
[5,] 1 1 1 0 0 0 1 1 1 1
[6,] 1 1 1 1 0 0 0 1 1 1
[7,] 0 1 1 1 1 0 0 0 1 1
[8,] 0 0 1 1 1 1 0 0 0 1
[9,] 0 0 0 1 1 1 1 0 0 0
[10,] 0 0 0 0 1 1 1 1 0 0
Here is Matlab code to form the matrix of logical values of '0' and '1'
A=[1 2 3 4 5 6 7 8 9 10 ];
N = numel(A);
step = 2; % Set this to however many zeros you want to add each column
index = N:-step:1;
val = (1:N+step).' <= index;
Which result in
val=
1 1 1 1 1
1 1 1 1 1
1 1 1 1 0
1 1 1 1 0
1 1 1 0 0
1 1 1 0 0
1 1 0 0 0
1 1 0 0 0
1 0 0 0 0
1 0 0 0 0
0 0 0 0 0
0 0 0 0 0
How to do same task in r ,particularly val = (1:N+step).' <= indexthis step?
One option is
i <- seq_len(ncol(m1))
sapply(rev(i), function(.i) {
m1[,.i][sequence(.i *2)] <- 1
m1[,.i]
})
# [,1] [,2] [,3] [,4] [,5]
# [1,] 1 1 1 1 1
# [2,] 1 1 1 1 1
# [3,] 1 1 1 1 0
# [4,] 1 1 1 1 0
# [5,] 1 1 1 0 0
# [6,] 1 1 1 0 0
# [7,] 1 1 0 0 0
# [8,] 1 1 0 0 0
# [9,] 1 0 0 0 0
#[10,] 1 0 0 0 0
#[11,] 0 0 0 0 0
#[12,] 0 0 0 0 0
Or vectorize it
i1 <- rep(i, rev(2*i))
m1[cbind(ave(i1, i1, FUN = seq_along), i1)] <- 1
m1
# [,1] [,2] [,3] [,4] [,5]
# [1,] 1 1 1 1 1
# [2,] 1 1 1 1 1
# [3,] 1 1 1 1 0
# [4,] 1 1 1 1 0
# [5,] 1 1 1 0 0
# [6,] 1 1 1 0 0
# [7,] 1 1 0 0 0
# [8,] 1 1 0 0 0
# [9,] 1 0 0 0 0
#[10,] 1 0 0 0 0
#[11,] 0 0 0 0 0
#[12,] 0 0 0 0 0
Or another option without creating a matrix beforehand
n <- 5
i1 <- seq(10, 2, by = -2)
r1 <- c(rbind(i1, rev(i1)))
matrix(rep(rep(c(1, 0), n), r1), ncol = n)
# [,1] [,2] [,3] [,4] [,5]
# [1,] 1 1 1 1 1
# [2,] 1 1 1 1 1
# [3,] 1 1 1 1 0
# [4,] 1 1 1 1 0
# [5,] 1 1 1 0 0
# [6,] 1 1 1 0 0
# [7,] 1 1 0 0 0
# [8,] 1 1 0 0 0
# [9,] 1 0 0 0 0
#[10,] 1 0 0 0 0
#[11,] 0 0 0 0 0
#[12,] 0 0 0 0 0
data
m1 <- matrix(0, 12, 5)
I want to make all combinations of my Matrix.
Ex. a binary 5 X 5 matrix where I only have two 1 rows (see below)
Com 1:
1 1 0 0 0
1 1 0 0 0
1 1 0 0 0
1 1 0 0 0
1 1 0 0 0
Com 2:
1 0 1 0 0
1 1 0 0 0
1 1 0 0 0
1 1 0 0 0
1 1 0 0 0
.
.
.
Com ?:
0 0 0 1 1
0 0 0 1 1
0 0 0 1 1
0 0 0 1 1
0 0 0 1 1
I tried using Combination package in R, but couldn't find a solution.
Using RcppAlgos (I am the author) we can accomplish this with 2 calls. It's quite fast as well:
library(tictoc)
library(RcppAlgos)
tic("RcppAlgos solution")
## First we generate the permutations of the multiset c(1, 1, 0, 0, 0)
binPerms <- permuteGeneral(1:0, 5, freqs = c(2, 3))
## Now we generate the permutations with repetition choose 5
## and select the rows from binPerms above
allMatrices <- permuteGeneral(1:nrow(binPerms), 5,
repetition = TRUE,
FUN = function(x) {
binPerms[x, ]
})
toc()
RcppAlgos solution: 0.108 sec elapsed
Here is the output:
allMatrices[1:3]
[[1]]
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 0 0 0
[2,] 1 1 0 0 0
[3,] 1 1 0 0 0
[4,] 1 1 0 0 0
[5,] 1 1 0 0 0
[[2]]
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 0 0 0
[2,] 1 1 0 0 0
[3,] 1 1 0 0 0
[4,] 1 1 0 0 0
[5,] 1 0 1 0 0
[[3]]
[,1] [,2] [,3] [,4] [,5]
[1,] 1 1 0 0 0
[2,] 1 1 0 0 0
[3,] 1 1 0 0 0
[4,] 1 1 0 0 0
[5,] 1 0 0 1 0
len <- length(allMatrices)
len
[1] 100000
allMatrices[(len - 2):len]
[[1]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0 0 0 1 1
[2,] 0 0 0 1 1
[3,] 0 0 0 1 1
[4,] 0 0 0 1 1
[5,] 0 0 1 1 0
[[2]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0 0 0 1 1
[2,] 0 0 0 1 1
[3,] 0 0 0 1 1
[4,] 0 0 0 1 1
[5,] 0 0 1 0 1
[[3]]
[,1] [,2] [,3] [,4] [,5]
[1,] 0 0 0 1 1
[2,] 0 0 0 1 1
[3,] 0 0 0 1 1
[4,] 0 0 0 1 1
[5,] 0 0 0 1 1
The code I've written below worked for me. A list of 100,000 5x5 matrices. Each of the rows has two places set to 1.
n <- 5 # No of columns
k <- 2 # No. of ones
m <- 5 # No of rows in matrix
nck <- combn(1:n,k,simplify = F)
possible_rows <-lapply(nck,function(x){
arr <- numeric(n)
arr[x] <- 1
matrix(arr,nrow=1)
})
mat_list <- possible_rows
for(i in 1:(m-1)){
list_of_lists <- lapply(mat_list,function(x){
lapply(possible_rows,function(y){
rbind(x,y)
})
})
mat_list <- Reduce(c,list_of_lists)
print(c(i,length(mat_list)))
}
I have a graph that converted to matrix.
g = sample_k_regular(10,3)
m =get.adjacency(g)
I want to select randomly some elements and convert to 0|1.(if it is 0 to become 1 and if it is 1 to become 0).
How to do this work?
You can make sample of n elements (10 in example) and change it
m1=as.matrix(m)
m1
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 0 0 1 1 0 0 0 0 1 0
[2,] 0 0 0 0 1 0 0 0 1 1
[3,] 1 0 0 0 0 0 0 1 0 1
[4,] 1 0 0 0 1 0 1 0 0 0
[5,] 0 1 0 1 0 1 0 0 0 0
[6,] 0 0 0 0 1 0 1 0 0 1
[7,] 0 0 0 1 0 1 0 1 0 0
[8,] 0 0 1 0 0 0 1 0 1 0
[9,] 1 1 0 0 0 0 0 1 0 0
[10,] 0 1 1 0 0 1 0 0 0 0
set.seed(1)
ss=sample(length(m1),size = 10)
m1[ss]=1-m1[ss]
m1
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 0 0 1 1 0 0 0 0 1 0
[2,] 0 0 0 0 1 0 1 0 1 1
[3,] 1 0 0 0 0 0 0 1 0 1
[4,] 1 0 0 0 1 0 1 0 0 0
[5,] 0 1 0 1 0 1 0 0 0 0
[6,] 1 0 0 0 1 0 1 0 1 1
[7,] 0 0 1 0 0 0 0 1 0 1
[8,] 0 0 1 0 0 1 1 0 1 0
[9,] 1 1 0 0 0 0 0 1 1 0
[10,] 0 0 1 0 0 1 0 0 0 0
For exclude diagonal as #ZheyuanLi told
you can calculate diad position and exlude it from data for sample :
m1=as.matrix(m)
m1
set.seed(1)
m_l=1:length(m1)
m_l=m_l[-which(diag(1,nrow = nrow(m1))==1)]
ss=sample(m_l,size = 10)
m1[ss]=1-m1[ss]
m1
For big matrix beter use seq.int than diag
n=1000
Unit: microseconds
expr min lq mean median uq max neval
{ which(diag(1, nrow = n) == 1) } 8976.718 9422.967 14397.44991 10489.0520 16001.550 190959.200 100
{ seq(1, by = n + 1, length = n) } 12.941 17.404 37.90449 31.9075 56.004 83.448 100
{ seq.int(1, by = n + 1, length = n) } 5.355 6.248 8.90736 7.1405 12.272 16.512 100
{ 1 + { (1:n) - 1 } * (1 + n) } 5.355 6.248 9.77758 8.9255 11.826 25.437 100
How to transform a matrix like
A 1 2 3
B 3 6 9
c 5 6 9
D 1 2 4
into form like:
1 2 3 4 5 6 7 8 9
1 0 2 1 1 0 0 0 0 0
2 0 0 1 1 0 0 0 0 0
3 0 0 0 0 0 1 0 0 1
4 0 0 0 0 0 0 0 0 0
5 0 0 0 0 0 1 0 0 1
6 0 0 0 0 0 0 0 0 2
7 0 0 0 0 0 0 0 0 0
8 0 0 0 0 0 0 0 0 0
9 0 0 0 0 0 0 0 0 0
I have some implement for it ,but it use the for loop
I wonder if there has some inner function in R (for example "apply")
add:
Sorry for the confusion.The first matrix just mean items sets, every set of items come out pairs ,for example the first set is "1 2 3" , and will become (1,2),(1,3),(2,3), correspond the second matrix.
and another question :
If the matrix is very large (10000000*10000000)and is sparse
should I use sparse matrix or big.matrix?
Thanks!
Removing the row names from M gives this:
m <- matrix(c(1,3,5,1,2,6,6,2,3,9,9,4), nrow=4)
> m
## [,1] [,2] [,3]
## [1,] 1 2 3
## [2,] 3 6 9
## [3,] 5 6 9
## [4,] 1 2 4
# The indicies that you want to increment in x, but some are repeated
# combn() is used to compute the combinations of columns
indices <- matrix(t(m[,combn(1:3,2)]),,2,byrow=TRUE)
# Count repeated rows
ones <- rep(1,nrow(indices))
cnt <- aggregate(ones, by=as.data.frame(indices), FUN=sum)
# Set each value to the appropriate count
x <- matrix(0, 9, 9)
x[as.matrix(cnt[,1:2])] <- cnt[,3]
x
## [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
## [1,] 0 2 1 1 0 0 0 0 0
## [2,] 0 0 1 1 0 0 0 0 0
## [3,] 0 0 0 0 0 1 0 0 1
## [4,] 0 0 0 0 0 0 0 0 0
## [5,] 0 0 0 0 0 1 0 0 1
## [6,] 0 0 0 0 0 0 0 0 2
## [7,] 0 0 0 0 0 0 0 0 0
## [8,] 0 0 0 0 0 0 0 0 0
## [9,] 0 0 0 0 0 0 0 0 0