Creating or initializing an empty matrix in R

Question

I am using R v 3.0.0 (2013-04-03) and RStudio v 1.1.463 under Win-7 64-bit.

In the following source code:

# Problem 1 - Matrix powers in R
#
# R does not have a built-in command for taking matrix powers. 
# Write a function matrixpower with two arguments mat and k that 
# will take integer powers k of a matrix mat.
matrixMul <- function(mat1)
{
  rows <- nrow(mat1)
  cols <- ncol(mat1)

  matOut = matrix(, nrow = rows, ncol = cols) # empty matrix

  for (i in 1:rows) 
  {
    for(j in 1:cols)
    {
      vec1 <- mat1[i,]
      vec2 <- mat1[,j]

      mult1 <- vec1 * vec2

      matOut[i,j] <- mult1
    }
  }

  return(matOut) 
}

matrixpower<-function(mat1, k)
{
  matOut <-mat1#empty matix

  for (i in k) 
  {
    matOut <- matrixMul(matOut)
  }

  return(matOut) 
}

mat1 <- matrix(c(1,2,3,4,5,6,7,8,9), nrow = 3, ncol=3)

power1 <- matrixMul(mat1)

the declaration

matOut <- matrix(, nrow = rows, ncol = cols) # empty matrix

is giving the following syntax error even before compilation:

missing argument to function call

I am following these instructions.

What am I doing wrong here?

You completely changed your question (after the initial one got solved) and that is not how SO works. — Julius Vainora, Apr 24 '19 at 19:08

score 2 · Accepted Answer · answered Apr 24 '19 at 19:00

2

Try this:

matOut = matrix(numeric(rows*cols), nrow = rows, ncol = cols) # empty matrix

answered Apr 24 '19 at 19:00

tushaR

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Creating or initializing an empty matrix in R

1 Answers1