Implemented cachematrix.R

amaroRafael · amaroRafael · commit 022328a2f070 · 2015-04-21T22:31:27.000-03:00
diff --git a/.Rapp.history b/.Rapp.history
@@ -0,0 +1,101 @@
+my_score <- c(16,20,20,36)
+max_score <- c(20,20,20,41)
+weight <- c(20,20,20,40)
+grade_achieved <- 100 * weighted.mean(my_score / max_score, weight)
+grade_achieved
+getwd()
+dir()
+x <- 2
+attributes(x)
+x
+attributes()
+attributes(x)
+q()
+x <- 4
+class(x)
+x <- c(4,"a",TRUE)
+class(x)
+x <- c("a","b","c")
+seq_along(x)
+rbinom(1, 1, 0.5)
+cube <- function(x, n) {}
+cube <- function(x, n) {
+x^3
+}
+cube(3)
+x <- 1:10#
+if(x > 5) {#
+        x <- 0#
+}
+f <- function(x) {#
+        g <- function(y) {#
+                y + z#
+        }#
+        z <- 4#
+        x + g(x)#
+}
+z <- 10
+f(3)
+x <- 5#
+y <- if(x < 3) {#
+        NA#
+} else {#
+        10#
+}
+y
+h <- function(x, y = NULL, d = 3L) {#
+        z <- cbind(x, d)#
+        if(!is.null(y))#
+                z <- z + y#
+        else#
+                z <- z + f#
+        g <- x + y / z#
+        if(d == 3L)#
+                return(g)#
+        g <- g + 10#
+        g#
+}
+getwd()
+setwd("/Users/ramaro/GIT/ProgrammingAssignment2/")
+getwd()
+c <- rbind(c(1, -1/4), c(-1/4, 1))
+c
+ic <- solve(c)
+ic
+ic <- solve(c) * c
+ic
+ic <- solve(c) %*% c
+ic
+library("MASS")
+ic <- ginv(c)
+ic
+c <- rbind(c(1, -1), c(-1, 1))
+c
+ic <- solve(c)
+ic <- ginv(c)
+ic
+ic <- solve(c)
+det(c)
+b <- rbind(c(3,6,3),c(5,2,1),c(1,2,1))
+b
+det(b)
+solve(b)
+ginv(b)
+source(cachematrix.R)
+source("cachematrix.R")
+ma <- makeCacheMatrix(rbind(c(1, -1/4), c(-1/4, 1)))
+ma
+cacheSolve(ma)
+cacheSolve(ma)
+ma$get()
+ma <- makeCacheMatrix(c)
+cacheSolve(ma)
+ma <- makeCacheMatrix(b)
+cacheSolve(ma)
+source(cachematrix.R)
+source("cachematrix.R")
+cacheSolve(ma)
+ma <- makeCacheMatrix(rbind(c(1, -1/4), c(-1/4, 1)))
+cacheSolve(ma)
+ma <- makeCacheMatrix(c)
+cacheSolve(ma)
diff --git 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 short comment describing this function
+## Computes the inverse of the "matrix"
+## if the inverse has already been calculated (and the matrix has not changed),
+## then the cachesolve should retrieve the inverse from the cache
 
+## This function creates a speacial "matrix" object that can cache its inverse
 makeCacheMatrix <- function(x = matrix()) {
-
+	mi <- NULL
+	set <- function(y){
+		x <<- y
+		mi <<- NULL
+	}
+	get <- function() x
+	setinverse <- function(minverse) mi < minverse
+	getinverse <- function() mi
+	list(set = set, get = get,
+		setinverse = setinverse,
+		getinverse = getinverse)
 }
 
-
-## Write a short comment describing this function
-
+## Computing the inverse of a square matrix
 cacheSolve <- function(x, ...) {
-        ## Return a matrix that is the inverse of 'x'
+        ## Return a matrix that is the inverse of 'x' 
+        mi <- x$getinverse()
+        if (!is.null(mi)) {
+        	return(mi)
+        }
+        m <- x$get()
+        
+        d <- det(m)
+        
+        if(d > 0) {
+        	mi <- solve(m)
+        	x$setinverse(mi)
+        }
+        
+        mi
 }
