On Sunday, 24 March 2024 at 21:21:13 UTC, kdevel wrote:
Usually you do not translate mathematical expressions directly
into code:
```
n += pow(-1.0, i - 1.0) / (i * 2.0 - 1.0);
```
The term containing the `pow` invocation computes the
alternating sequence -1, 1, -1, ..., which can be replaced by
e.g.
```
immutable int [2] sign = [-1, 1];
n += sign [i & 1] / (i * 2.0 - 1.0);
```
This saves the expensive call to the pow function.
I know that the code can be simplified/optimized, I just wanted
to compare the same expression in C and D.
