Chapter 24.Rmd

---
title: "Chapter 24"
author: "Julin Maloof"
date: "2023-09-13"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

```{r}
library(bench)
library(tidyverse)
```

## 24.3.1 Exercises

### 1. What are faster alternatives to lm()? Which are specifically designed to work with larger datasets?
lsfit
lm.fit
fastlm
.lm.fit
speedlm

### 2. What package implements a version of match() that’s faster for repeated lookups? How much faster is it?

fastmatch

### 4. rolling mean

rollmean from zoo

### 5. optim alternatives

optimParallel

```{r}
x1 <- rnorm(10000)
w1 <- runif(10000)
x2 <- rnorm(10000000)
w2 <- runif(10000000)
cp1 <- function(x,w) crossprod(x,w)[[1]]
cp2 <- function(x,w) sum(x*w)

r1 <- mark(crossprod10K=cp1(x1,w1),
  sum10K=cp2(x1,w1)) %>%
  mutate(expression=names(expression))

r2 <-mark(
  crossprod10M=cp1(x2,w2),
  sum10M=cp2(x2,w2)) %>%
  mutate(expression=names(expression))

bind_rows(r1,r2)
```