From 6734f2f1bcdab8f0d50524a26195707da00bd8ed Mon Sep 17 00:00:00 2001 From: Remco Bloemen Date: Thu, 23 Aug 2018 15:18:55 -0700 Subject: Add docs --- packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'packages') diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol index 1c14dbcae..8a1444af1 100644 --- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol +++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol @@ -74,7 +74,7 @@ contract LibMath is return partialAmount; } - /// @dev Checks if rounding error > 0.1%. + /// @dev Checks if rounding error >= 0.1% when rounding down. /// @param numerator Numerator. /// @param denominator Denominator. /// @param target Value to multiply with numerator/denominator. @@ -121,7 +121,7 @@ contract LibMath is return isError; } - /// @dev Checks if rounding error > 0.1%. + /// @dev Checks if rounding error >= 0.1% when rounding up. /// @param numerator Numerator. /// @param denominator Denominator. /// @param target Value to multiply with numerator/denominator. @@ -137,9 +137,14 @@ contract LibMath is { require(denominator > 0, "DIVISION_BY_ZERO"); + // See the comments in `isRoundingError`. if (target == 0 || numerator == 0) { + // When either is zero, the ideal value and rounded value are zero + // and there is no rounding error. (Although the relative error + // is undefined.) return false; } + // Compute remainder as before uint256 remainder = mulmod(target, numerator, denominator); // TODO: safeMod remainder = safeSub(denominator, remainder) % denominator; -- cgit v1.2.3