灌裝中的R

Question

一個矩陣一定條件給定尺寸和MN的矩陣， 我們要填充的整數值在每一行中（> = 0） 使得其總計爲一定值。

注意的M和N尺寸是預先計算使用 某些式，以便它是保證匹配 給出的期望的條件的填充（即sum_val下文）。

這兩個例子

#sum_val <-2 
#m<-6 
#n<-3 

# the value of "sum_val" may vary 
# and 'm' 'n' also change depends on it 

# First are initialized using 0 
#mat <- matrix(0,nrow=m,ncol=n); 


# Below results are hand coded: 
     [,1] [,2] [,3] 
[1,] 1 1 0 # Sum of each rows here is equal to 'sum_val = 2' 
[2,] 1 0 1 
[3,] 0 1 1 
[4,] 2 0 0 
[5,] 0 2 0 
[6,] 0 0 2 

又如：

> sum_val<-2; 
#m<-15 
#n<-5 
#mat <- matrix(0,nrow=m,ncol=n); 

# Below results are hand coded: 
     [,1] [,2] [,3] [,4] [,5] 
[1,] 1 1 0 0 0 # rows also sums up to 2 
[2,] 1 0 1 0 0 
[3,] 1 0 0 1 0 
[4,] 1 0 0 0 1 
[5,] 0 1 0 0 1 
[6,] 0 0 1 0 1 
[7,] 0 0 0 1 1 
[8,] 0 1 0 1 0 
[9,] 0 1 1 0 0 
[10,] 0 0 1 1 0 
[11,] 2 0 0 0 0 
[12,] 0 2 0 0 0 
[13,] 0 0 2 0 0 
[14,] 0 0 0 2 0 
[15,] 0 0 0 0 2 

我卡具有以下循環：

> for (ri in 1:m) { 
+  for (ci in 1:n) { 
+  
+   
+  # Not sure how to proceed from here 
+  if(ci==2) { 
+    mat[ri,ci] <- 1; 
+  } 
+  } 
+ } 

什麼是解決這個問題的最好方法？

Answer 1

下面是我如何解決它！

library(partitions) 

sum_val <- 2 
n <- 5 

t(as.matrix(compositions(sum_val, n))) 
     [,1] [,2] [,3] [,4] [,5] 
[1,] 2 0 0 0 0 
[2,] 1 1 0 0 0 
[3,] 0 2 0 0 0 
[4,] 1 0 1 0 0 
[5,] 0 1 1 0 0 
[6,] 0 0 2 0 0 
[7,] 1 0 0 1 0 
[8,] 0 1 0 1 0 
[9,] 0 0 1 1 0 
[10,] 0 0 0 2 0 
[11,] 1 0 0 0 1 
[12,] 0 1 0 0 1 
[13,] 0 0 1 0 1 
[14,] 0 0 0 1 1 
[15,] 0 0 0 0 2