position: PSA: apply the double-angle sine formula #61
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Apply the double-angle sine formula:
```
sin(2 * x) = 2 * sin(x) * cos(x)
```
The idea is:
* `sin(x)` and `sin(2 * x)` both appear as subexpressions within the
same expression
* computing `sin(x)` and `cos(x)` could conceivably be faster than
computing directly `sin(x)` and `sin(2 * x)`, because `sin(x)` and
`cos(x)` use the same polynomials in their implementations
* this relies on the compiler being smart enough
* this perhaps also relies on luck regarding things like inlining
heuristics
nsajko
commented
Jan 5, 2026
Benchmark Results (Julia vlts)Time benchmarks
Memory benchmarks
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Benchmark Results (Julia vpre)Time benchmarks
Memory benchmarks
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Benchmark Results (Julia v1)Time benchmarks
Memory benchmarks
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #61 +/- ##
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Coverage 100.00% 100.00%
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Files 17 17
Lines 678 679 +1
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+ Hits 678 679 +1 ☔ View full report in Codecov by Sentry. 🚀 New features to boost your workflow:
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Contributor
Author
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CI fails, but the failure does not seem caused by the change in this PR: |
Member
|
Yes I see, that's because I also see more allocations on version 1.12.4. I have seen that in other places (outside SolarPosition.jl) as well, I will investigate what's causing that. |
Member
|
If you sync your branch the checks should pass now. |
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Apply the double-angle sine formula:
The idea is:
sin(x)andsin(2 * x)both appear as subexpressions within the same expressioncomputing
sin(x)andcos(x)could conceivably be faster than computing directlysin(x)andsin(2 * x), becausesin(::Float64)andcos(::Float64)use the same polynomials in their implementationsthis relies on the compiler being smart enough
this perhaps also relies on luck regarding things like inlining heuristics
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