feat: improve accuracy for atan2(y,x) when x is near-zero #19
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`atan2(y,x)` requires a lot of bits in the integer part when `x` is near-zero. This is because `atan2(y,x)` does `atan(y/x)` internally and `y/x` easily overflows for very small `x` unless you have more integer bits than fraction bits. However, `atan(q)` does `1/q` if `q > 1`, thereby inverting the original division in `atan2`. So this overflow can be avoided if these divisions are shortcut. Closes #18
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atan2(y,x)requires a lot of bits in the integer part whenxis near-zero. This is becauseatan2(y,x)doesatan(y/x)internally andy/xeasily overflows for very smallxunless you have more integer bits than fraction bits.However,
atan(q)does1/qifq > 1, thereby inverting the original division inatan2. So this overflow can be avoided if these divisions are shortcut.Closes #18