Initial commit: Pi calculation benchmark with 34 languages

- Added implementations for: bash, brainfuck, c, cpp, crystal, csharp, d, dart, elixir, erlang, fortran, go, haskell, java, javascript, julia, kotlin, objective-c, scala, typescript, lua, nim, odin, perl, php, python, r, ruby, rust, swift, zig, assembly, vimscript, wolfram - All implementations use Machin's formula: π/4 = 4*arctan(1/5) - arctan(1/239) - Build system with ./build.sh, test system with ./test.sh - Performance testing with ./run_all.sh - Comprehensive README.md explaining performance differences - Test framework verifies correctness against known π values
2026-04-23 00:26:18 +02:00
commit 54d2fecee0
182 changed files with 17471 additions and 0 deletions
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+-module(pi_test).
+-include_lib("eunit/include/eunit.hrl").
+
+-define(SCRIPT_PATH, "/Users/einand/Code/test/erlang/print_hej").
+
+run_script(Args) ->
+    Cmd = ?SCRIPT_PATH ++ " " ++ Args,
+    Port = open_port({spawn, Cmd}, [stream, exit_status]),
+    receive
+        {Port, {data, Output}} ->
+            port_close(Port),
+            string:trim(Output, trailing, "\n");
+        {Port, {exit_status, _Status}} ->
+            port_close(Port),
+            ""
+    after 5000 ->
+        port_close(Port),
+        ""
+    end.
+
+run_script_no_args() ->
+    Cmd = ?SCRIPT_PATH,
+    Port = open_port({spawn, Cmd}, [stream, exit_status]),
+    receive
+        {Port, {data, Output}} ->
+            port_close(Port),
+            string:trim(Output, trailing, "\n");
+        {Port, {exit_status, _Status}} ->
+            port_close(Port),
+            ""
+    after 5000 ->
+        port_close(Port),
+        ""
+    end.
+
+test_10_decimals_test() ->
+    Result = run_script("10"),
+    Expected = "3.1415926535",
+    ?assertEqual(Expected, Result).
+
+test_5_decimals_test() ->
+    Result = run_script("5"),
+    Expected = "3.14159",
+    ?assertEqual(Expected, Result).
+
+test_1_decimal_test() ->
+    Result = run_script("1"),
+    Expected = "3.1",
+    ?assertEqual(Expected, Result).
+
+test_100_decimals_test() ->
+    Result = run_script("100"),
+    Expected = "3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679",
+    ?assertEqual(Expected, Result).
+
+test_default_100_decimals_test() ->
+    Result = run_script_no_args(),
+    Expected = "3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679",
+    ?assertEqual(Expected, Result).
+
+test_10000_decimals_test() ->
+    Result = run_script("10000"),
+    % Check length: "3." + 10000 digits = 10002 characters
+    ?assertEqual(10002, length(Result)),
+    ?assert(lists:prefix("3.14159", Result)).
@@ -0,0 +1,64 @@
+-module(print_hej).
+-export([main/1, pow/2]).
+
+main(Args) ->
+    Decimals = case Args of
+                   [] -> 100;
+                   [X | _] ->
+                       case string:to_integer(X) of
+                           {D, _} when D > 0 -> D;
+                           _ -> 100
+                       end
+               end,
+    
+    Pi = calculate_pi(Decimals),
+    PiStr = format_pi(Pi, Decimals),
+    io:format("~s~n", [PiStr]),
+    erlang:halt(0).
+
+% Calculate arctan(1/x) using Taylor series
+% arctan(1/x) = 1/x - 1/(3*x^3) + 1/(5*x^5) - ...
+arctan(X, Decimals) ->
+    Scale = pow(10, Decimals + 10),
+    XSquared = X * X,
+    Term = Scale div X,  % First term: scale / x
+    arctan_iter(XSquared, Term, 0, 0, Decimals).
+
+arctan_iter(_XSquared, Term, N, Result, Decimals) when Term == 0; N > Decimals * 3 ->
+    Result;
+arctan_iter(XSquared, Term, N, Result, Decimals) ->
+    Divisor = 2 * N + 1,
+    Contrib = Term div Divisor,
+    NewResult = case N rem 2 of
+                   0 -> Result + Contrib;
+                   1 -> Result - Contrib
+               end,
+    NewTerm = Term div XSquared,  % Divide by x² each iteration
+    arctan_iter(XSquared, NewTerm, N + 1, NewResult, Decimals).
+
+% Calculate pi using Machin's formula
+% pi/4 = 4*arctan(1/5) - arctan(1/239)
+calculate_pi(Decimals) ->
+    Atan1_5 = arctan(5, Decimals),
+    Atan1_239 = arctan(239, Decimals),
+    16 * Atan1_5 - 4 * Atan1_239.
+
+% Format pi with decimal point
+format_pi(Pi, Decimals) ->
+    PiStr = integer_to_list(Pi),
+    % Pad with leading zeros if needed
+    PiStr2 = case length(PiStr) < Decimals + 10 of
+                true -> string:left(PiStr, Decimals + 10, $0);
+                false -> PiStr
+            end,
+    "3." ++ string:substr(PiStr2, 2, Decimals).
+
+% Power function for integers
+pow(Base, Exp) when Exp >= 0 ->
+    pow_iter(Base, Exp, 1).
+
+pow_iter(_Base, 0, Acc) -> Acc;
+pow_iter(Base, Exp, Acc) when Exp rem 2 == 0 ->
+    pow_iter(Base * Base, Exp div 2, Acc);
+pow_iter(Base, Exp, Acc) ->
+    pow_iter(Base, Exp - 1, Acc * Base).