From d9a4e615d3f3c39d92ed2069dc824ffadd8815e1 Mon Sep 17 00:00:00 2001
From: lareelarr <lareelarr@gmail.com>
Date: Sat, 21 Sep 2019 22:56:12 -0400
Subject: [PATCH 1/2] Updated the function shells with the proper code.

---
 cachematrix.R | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index a50be65aa44..623769b15f4 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,15 +1,37 @@
-## Put comments here that give an overall description of what your
-## functions do
+## Write a pair of functions that cache the inverse of a matrix.
 
-## Write a short comment describing this function
+## makeCacheMatrix: This function creates a special "matrix" object that test
+## can cache its inverse.
 
 makeCacheMatrix <- function(x = matrix()) {
-
+  i <- NULL
+  set <- function(y) {
+    x <<- y
+    i <<- NULL
+  }
+  get <- function() x
+  setinv <- function(solve) i <<- solve
+  getinv <- function() i
+  list(set = set, get = get,
+       setinv = setinv,
+       getinv = getinv)
 }
 
 
-## Write a short comment describing this function
+## This function 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'
+  i <- x$getinv()
+  if(!is.null(i)) {
+    message("getting cached data")
+    return(i)
+  }
+  data <- x$get()
+  i <- solve(data, ...)
+  x$setinv(i)
+  i
 }

From 2b6609a9e51798d94fd4d0ac232f46cc50ab3a8d Mon Sep 17 00:00:00 2001
From: Larry Mannings <lareelarr@gmail.com>
Date: Wed, 26 Nov 2025 00:23:47 -0500
Subject: [PATCH 2/2] Redid the assignment as a refresher

---
 cachematrix.R | 84 +++++++++++++++++++++++++++++++++------------------
 1 file changed, 54 insertions(+), 30 deletions(-)

diff --git a/cachematrix.R b/cachematrix.R
index 623769b15f4..926b0fc9b6b 100644
--- a/cachematrix.R
+++ b/cachematrix.R
@@ -1,37 +1,61 @@
-## Write a pair of functions that cache the inverse of a matrix.
+# Written by Larry Mannings, 25 November 2025
 
-## makeCacheMatrix: This function creates a special "matrix" object that test
-## can cache its inverse.
+# makeCacheMatrix() function leverages the makeVector example from R Programming
+# Ass. 2, modified to create a list consisting of cached matrix and 
+# corresponding inverse.
 
-makeCacheMatrix <- function(x = matrix()) {
-  i <- NULL
-  set <- function(y) {
-    x <<- y
-    i <<- NULL
-  }
-  get <- function() x
-  setinv <- function(solve) i <<- solve
-  getinv <- function() i
-  list(set = set, get = get,
-       setinv = setinv,
-       getinv = getinv)
+makeCacheMatrix <- function(x = numeric()) {
+    
+    # x is numeric matrix object representing an invertible matrix
+    # i is matrix object representing inverse of matrix object (x)
+    
+    # Initialize the inverse matrix to NULL
+    i <- NULL
+    
+    # Set the value of the matrix
+    set <- function(y) {
+        x <<- y
+        i <<- NULL
+    }
+    # Get the value of the matrix
+    get <- function() x
+    
+    # Set the value of the inverse matrix
+    setinv <- function(inv) i <<- inv
+    
+    # Get the value of the inverse matrix
+    getinv <- function() i
+    
+    # Store objects in a list and return
+    list(set = set, get = get,
+         setinv = setinv,
+         getinv = getinv)
 }
 
 
-## This function 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 leverages the cachemean() example from R Programming
+# Ass. 2, modified to compute the inverse of the returned by 
+# makeCacheMatrix() function.
 
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
-  i <- x$getinv()
-  if(!is.null(i)) {
-    message("getting cached data")
-    return(i)
-  }
-  data <- x$get()
-  i <- solve(data, ...)
-  x$setinv(i)
-  i
-}
+    
+    # x is list object representing constructed from the makeCacheMatrix 
+    # function
+    # i is matrix object representing inverse of matrix object (x)
+    
+    # Call the getinv(function) as a list object to get matrix inverse 
+    i <- x$getinv()
+    # If the inverse has already been calculated retrieve from the cache
+    if(!is.null(i)) {
+        message("getting cached data")
+        return(i)
+    }
+    # Else, retrieve the cached matrix and solve for the inverse matrix
+    data <- x$get()
+    i <- solve(data, ...)
+    # Cache the inverse matrix and return value
+    x$setinv(i)
+    i
+}
\ No newline at end of file