tested and fixed

Author: twoerth

cachematrix.R

@@ -2,53 +2,72 @@
 
 ## Build the matrix wrapper
 makeCacheMatrix <- function(x = matrix()) {
-	## by default we do not have an inverse.
-	inv <- NULL
-
-	## Allow the caller to set a new matrix in place of the use used at initialisation.
-	set <- function( y ) {
-		x <<- y
-		## make sure an eventual cached inverse is cleared
-		inv <<- NULL
-	}
-	
-	## Return the matrix
-	get <- function() {
-		x
-	}
-	
-	## cache the inverse
-	setinverse <- function( inverse ) {
-		inv <<- inverse
-	}
-	
-	## return the inverse
-	getinverse <- function() {
-		inv
-	}
+  ## by default we do not have an inverse.
+  inv <- NULL
+  
+  ## Allow the caller to set a new matrix in place of the use used at initialisation.
+  set <- function( y ) {
+    x <<- y
+    ## make sure an eventual cached inverse is cleared
+    inv <<- NULL
+  }
+  
+  ## Return the matrix
+  get <- function() {
+    x
+  }
+  
+  ## cache the inverse
+  setinverse <- function( inverse ) {
+    inv <<- inverse
+  }
+  
+  ## return the inverse
+  getinverse <- function() {
+    inv
+  }
+  list( set = set, get = get, setinverse = setinverse, getinverse = getinverse )
 }
 
 
 ## Given an object returned by makeCacheMatrix, calculate the inverse and cache it for further calls.
 ## If a cached inverse has already been calculated on the wrapped matrix, the cached version is returned.
 cacheSolve <- function(x, ...) {
-	## Return a matrix that is the inverse of 'x'
-
-	inv <- x$getinverse
-
-	if( ! is.null( inv ) ) {
-		## The wrapped matrix has a non NULL inverse
-		message( "cache hit" )
-		return inv
-	}
-
-	## Calculate the inverse using solve
-	## TODO: handle special cases more carefully, not all matrices can be inverted.
-	inv <- solve( x$get() )
-
-	## Cache the result of solve()
-	x$setinverse( inv )
+  ## Return a matrix that is the inverse of 'x'
+  
+  inv <- x$getinverse()
+  
+  if( ! is.null( inv ) ) {
+    ## The wrapped matrix has a non NULL inverse
+    message( "cache hit" )
+    return( inv )
+  }
+  
+  ## Calculate the inverse using solve
+  ## TODO: handle special cases more carefully, not all matrices can be inverted.
+  inv <- solve( x$get() )
+  
+  ## Cache the result of solve()
+  x$setinverse( inv )
+  
+  ## return the inverse
+  inv
+}
 
-	## return the inverse
-	inv
-}
+##  Tested using:
+##  
+##  > m <- matrix(rnorm( 9 ), 3, 3)
+##  > 
+##  > 
+##  > cm <- makeCacheMatrix( m )
+##  > cacheSolve( cm )
+##            [,1]       [,2]      [,3]
+##  [1,]  2.371877  0.8502974  2.338579
+##  [2,]  0.960316 -1.2965751  1.011746
+##  [3,] -3.353513 -1.6878236 -5.258276
+##  > cacheSolve( cm )
+##  cache hit
+##            [,1]       [,2]      [,3]
+##  [1,]  2.371877  0.8502974  2.338579
+##  [2,]  0.960316 -1.2965751  1.011746
+##  [3,] -3.353513 -1.6878236 -5.258276