Project Overview

• Fibonacci number solver that operates as a process using GenServer
• The Fibonacci Solver is started and monitored by a supervisor
• Initial state cache contains a map of %{0 => 1, 1 => 1}
• It builds up answers as it decrements the provided input until reaching 2
• It caches the solved result and all answers it solved to figure it out

Benefits from Erlang

• Has one integer type and supports big integers, large numbers are computed without any additional logic in our implementation.
• Map type in state will handle big integers as values.
• Pattern matching and function overloading add simplicity.
• Using a supervisor to monitor the fib process, it is restarted if it dies.
• Able to use genserver to implement state, and messaging from other processes.

Possible Enhancements

Current Functionality

If it knows the answer (from cache) it is provided instantly.

Possible Enhancement

Use the largest answer it already knows to help solve new unknown fibs.

Current Functionality

Caches a map %{input => result} of all known values.

Possible Enhancement

Setting a range used to qualify if it should cache a result.
This would minimize the memory footprint by storing less items.

Current Functionality

Right now the cache is stored as long as the process has not died.

Possible Enhancement

Option for if a value should leave after no cache hit in a duration.

Instructions

iex -S mix run

Example Output

iex -S mix run
Erlang/OTP 21 [erts-10.0.7] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [hipe] [dtrace]
Interactive Elixir (1.7.3) - press Ctrl+C to exit (type h() ENTER for help)

iex(1)> Fib.solve 5
{:ok, 5}

iex(2)> Fib.solve 50
{:ok, 12586269025}

iex(3)> Fib.solve 500
{:ok,
 139423224561697880139724382870407283950070256587697307264108962948325571622863290691557658876222521294125}

iex(4)> Fib.solve 5000
{:ok,
 3878968454388325633701916308325905312082127714646245106160597214895550139044037097010822916462210669479293452858882973813483102008954982940361430156911478938364216563944106910214505634133706558656238254656700712525929903854933813928836378347518908762970712033337052923107693008518093849801803847813996748881765554653788291644268912980384613778969021502293082475666346224923071883324803280375039130352903304505842701147635242270210934637699104006714174883298422891491273104054328753298044273676822977244987749874555691907703880637046832794811358973739993110106219308149018570815397854379195305617510761053075688783766033667355445258844886241619210553457493675897849027988234351023599844663934853256411952221859563060475364645470760330902420806382584929156452876291575759142343809142302917491088984155209854432486594079793571316841692868039545309545388698114665082066862897420639323438488465240988742395873801976993820317174208932265468879364002630797780058759129671389634214252579116872755600360311370547754724604639987588046985178408674382863125}