cachematrix.R

# function creates object with get(), setInverse(), getInverse() functions
makeCacheMatrix <- function(x = matrix())
{
    cached_inverse <- NULL
    
    # returns matrix
    get <- function() 
    {
        x
    }
    
    # saves computer inverse
    setInverse <- function(inverse)
    {
        cached_inverse <<- inverse
    }
    
    # returns cached value of inverse or NULL
    getInverse <- function()
    {
        cached_inverse
    }
    
    list(get = get, setInverse = setInverse, getInverse = getInverse)
}


# Function returns inverse of matrix. 
# If inverse isn't cached, function makes necessary calculations and save it in cache by setInvert() function of source object
cacheSolve <- function(x)
{
    cached_inverse <- x$getInverse()
    
    if(!is.null(cached_inverse))
    {
      message("getting cached data")
      inverse <- cached_inverse
    }
    else
    {
      inverse <- solve(x$get())
      x$setInverse(inverse)
    }
    
    inverse
}

###########  TEST RESULTS #########################
# > mtr = matrix(1:4,2)
# > obj = makeCacheMatrix(mtr)
# > cacheSolve(obj)
# [,1] [,2]
# [1,]   -2  1.5
# [2,]    1 -0.5
# > cacheSolve(obj)
# getting cached data
# [,1] [,2]
# [1,]   -2  1.5
# [2,]    1 -0.5
# > cacheSolve(obj)
# getting cached data
# [,1] [,2]
# [1,]   -2  1.5
# [2,]    1 -0.5