[ViralBShah]

Sparse cond of a Float32 or ComplexF32 matrix returned Float64 when the matrix went through the LU and was nonsingular, but Float32 when it was singular (since #1126) or triangular, diagonal or positive definite. Dense cond returns Float32 in every case. Raised in the post-merge review of #1126.

Before

julia> cond(sparse(Float32[1 2; 3 4]), 1)
20.99999999999999

julia> cond(sparse(Float32[1 2; 3 6]), 1)
Inf32

julia> Base.return_types(cond, (SparseMatrixCSC{Float32,Int}, Int))
1-element Vector{Any}:
 Union{Float32, Float64}

After

julia> cond(sparse(Float32[1 2; 3 4]), 1)
21.0f0

julia> cond(sparse(Float32[1 2; 3 6]), 1)
Inf32

julia> Base.return_types(cond, (SparseMatrixCSC{Float32,Int}, Int))
1-element Vector{Any}:
 Float32

UMFPACK works in double precision, so the estimate of the inverse's norm is a Float64 for any eltype that takes the LU (a nonsymmetric matrix, or an indefinite Hermitian one where factorize falls back to lu), and opnorm(A, p) * normAinv promoted to it. cond now computes T = float(real(eltype(A))) once and returns zero(T), convert(T, Inf) or convert(T, opnorm(A, p) * normAinv). A sweep against dense cond over Int, Float32, Float64, ComplexF32, ComplexF64, Rational{Int}, BigFloat and Complex{BigFloat}, on general, singular, triangular, diagonal and Hermitian matrices, gives the dense result type in every case that runs; only the Float32 and ComplexF32 LU cases changed.

Potential breakage: cond of a nonsingular Float32 or ComplexF32 sparse matrix that is not triangular, diagonal or positive definite now returns Float32 instead of Float64, as dense cond does.

Written by Claude Code.

🤖 Generated with Claude Code

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.68%. Comparing base (2bef1fd) to head (ae3041d).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/linalg.jl	80.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1131      +/-   ##
==========================================
- Coverage   94.70%   94.68%   -0.02%     
==========================================
  Files          16       16              
  Lines       10423    10432       +9     
==========================================
+ Hits         9871     9878       +7     
- Misses        552      554       +2     

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