Update cachematrix.R

Author: IshPhanda

cachematrix.R

@@ -1,15 +1,75 @@
-## Put comments here that give an overall description of what your
-## functions do
+#Our aim in this experiment is to write a pair of functions, namely,
+#"makeCacheMatrix" and "cacheSolve" that cache the inverse of a matrix
 
-## Write a short comment describing this function
+#makeCacheMatrix is a function which creates a special "matrix" object that can
+#cache its inverse for the input (which is an invertible square matrix)
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  inv <- NULL
+  set <- function(y) {
+    x <<- y
+    inv <<- NULL
+  }
+  get <- function() x
+  setinv <- function(inverse) inv <<- inverse
+  getinv <- function() inv
+  list(set = set, get = get, setinv = setinv, getinv = getinv)
 }
 
 
-## Write a short comment describing this function
+#cacheSolve is a function which computes the inverse of the special "matrix"
+#returned by makeCacheMatrix above. If the inverse has already been calculated
+#(and the matrix has not changed), then the cachesolve should retrieve the
+#inverse from the cache
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+  inv <- x$getinv()
+  if(!is.null(inv)) {
+    message("getting cached result")
+    return(inv)
+  }
+  data <- x$get()
+  inv <- solve(data, ...)
+  x$setinv(inv)
+  inv
 }
+
+
+#Checking the Output-
+my_matrix <- makeCacheMatrix(matrix(1:4, 2, 2))
+my_matrix$get()
+# [,1] [,2]
+# [1,]    1    3
+# [2,]    2    4
+my_matrix$getinv()
+# NULL
+cacheSolve(my_matrix)
+# [,1] [,2]
+# [1,]   -2  1.5
+# [2,]    1 -0.5
+my_matrix$getinv()
+# [,1] [,2]
+# [1,]   -2  1.5
+# [2,]    1 -0.5
+
+
+my_matrix$set(matrix(c(2, 2, 1, 4), 2, 2))
+my_matrix$get()
+# [,1] [,2]
+# [1,]    2    1
+# [2,]    2    4
+my_matrix$getinv()
+# NULL
+cacheSolve(my_matrix)
+# [,1]       [,2]
+# [1,]  0.6666667 -0.1666667
+# [2,] -0.3333333  0.3333333
+cacheSolve(my_matrix)
+# getting cached result
+# [,1]       [,2]
+# [1,]  0.6666667 -0.1666667
+# [2,] -0.3333333  0.3333333
+my_matrix$getinv()
+# [,1]       [,2]
+# [1,]  0.6666667 -0.1666667
+# [2,] -0.3333333  0.3333333