reading_marsaglia.rmd

---
title: "Reading Marsaglia bits into R"
author: "alxfed"
date: "April 26, 2018"
output: pdf_document
---

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

## How to ingest Marsaglia bit files into R

The initial configuration: I have my Marsaglia bits in the root directory of my external (USB) hard drive, hence their address is: 
1. On Windows: F:\bits.01 and up to F:\bits.60
2. On Linux:   /media/alxfed/toca/bits.01 - bits.60

Here's the instruction. 

```{r}

# Windows version of file opening
# file_to_read = file(description = "F:/bits.42", open = "rb")
# "rb" which means read binary is important on Windows but
# equivalent to "r" on Linux and Unix (they say)

# Linux version of file opening
file_to_read = file(description = "/media/alxfed/toca/bits.42", open = "rb", raw = TRUE)

# Read n raw bytes from the file
A <- readBin(file_to_read, raw(), n = 10000000)
# raw() for bytes, integer() for integers etc.

# Then close the connection
close.connection(file_to_read)
```

We can test what has been read

```{r}
# This is what has been read
print(A[1:10])

# We need to transform the hexadecimal form of the raw
# bytes into integers if we want to use them
# notice that storing the data in the raw form as it was
# ingested stores 3x amount of memory.

print(as.integer(A[1:10]))
```

We can plot every 10000-th point and see whether the distribution is uniform enough

```{r}
n <- c(1:1000)
plot(n, as.integer(A[10000*n]))
```

Seems to be uniform enough

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