amountIn calculation formula bug

[lidd77]

hey,

Based on getAmountOut formula, we should not use 'add(1)' to calculate amountIn value.
But I find that getAmountIn function use 'add(1)' to calculate amountIn , I do not know why.
maybe its a bug ? .

Expecting your reply !

[kartikjn]

division in solidity takes the floor value, to compensate that loss in decimal, they are adding 1.

[fmdev99]

Should the formula for getAmountIn look like this?:

uint numerator = amountOut.mul(reserveIn).mul(1000);
uint denominator = reserveOut.mul(997).sub(amountOut.mul(1000));

[Samboy76]

I´m also having a similar issue in that whenever I perform getAmountsIn, the amountRequired ALWAYS supersedes the amountReceived via swapXXX function. Any ideas as to why is this happening?
Thank you

[Samboy76]

Should the formula for getAmountIn look like this?:

uint numerator = amountOut.mul(reserveIn).mul(1000); uint denominator = reserveOut.mul(997).sub(amountOut.mul(1000));

This would result in an ever worse amountRequired value over the amountReceived after a swap