solidity/test/libsolidity/semanticTests/externalContracts/ramanujan_pi.sol
2021-07-05 13:46:53 +02:00

45 lines
1.4 KiB
Solidity

==== ExternalSource: _prbmath/PRBMathCommon.sol ====
==== ExternalSource: _prbmath/PRBMathSD59x18.sol ====
==== Source: ramanujan_pi.sol ====
import "_prbmath/PRBMathSD59x18.sol";
// The goal of this test file is to implement Ramanujan's pi approximation using various libraries.
function factorial(uint n) pure returns (uint ret) {
ret = 1;
for (; n > 1; --n)
ret *= n;
}
contract test {
using PRBMathSD59x18 for int256;
function prb_scale(uint n) internal pure returns (int256 ret) {
// Scale to SD59x18
ret = int256(n * 10e17);
}
// This dumb implementation of Ramanujan series calculates 1/pi
function prb_pi() external pure returns (int256 ret) {
uint n = 6; // More than 6 iterations results in failure
for (uint k = 0; k < n; k++) {
int256 a = prb_scale(factorial(4 * k)).div(prb_scale(factorial(k)).pow(4));
int256 b = (prb_scale(25390).mul(prb_scale(k)) + prb_scale(1103)).div(prb_scale(396).pow(4 * k));
ret += a.mul(b);
}
ret = ret.mul(prb_scale(2).sqrt().mul(prb_scale(2)).div(prb_scale(99).pow(2)));
ret = prb_scale(1).div(ret);
}
}
// ====
// compileViaYul: also
// ----
// constructor()
// gas irOptimized: 500656
// gas legacy: 733634
// gas legacyOptimized: 478742
// prb_pi() -> 3141592656369545286
// gas irOptimized: 63037
// gas legacy: 98903
// gas legacyOptimized: 75735