JuliaLang / julia / #37712

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Build Type

push

local

Committed by web-flow

Commit Message

LinAlg: fzeropreserving unit triangular broadcast preserves structure (#53648)

On master
```julia
julia> UU = UnitUpperTriangular(reshape([1:9;],3,3))
3×3 UnitUpperTriangular{Int64, Matrix{Int64}}:
 1  4  7
 ⋅  1  8
 ⋅  ⋅  1

julia> UU .* 2
3×3 Matrix{Int64}:
 2  8  14
 0  2  16
 0  0   2
```
This PR
```julia
julia> UU .* 2
3×3 UpperTriangular{Int64, Matrix{Int64}}:
 2  8  14
 ⋅  2  16
 ⋅  ⋅   2
```
This also improves performance, as the `materialize` skips the
structured zeros.
```julia
julia> UU = UnitUpperTriangular(rand(100, 100));

julia> @btime $UU .* 2;
  12.788 μs (3 allocations: 78.20 KiB) # master
  7.821 μs (3 allocations: 78.20 KiB) # PR
```

Run Details

6 of 6 new or added lines in 1 file covered. (100.0%)

100 existing lines in 7 files now uncovered.

76365 of 88127 relevant lines covered (86.65%)

15665820.8 hits per line