add issuccess for CholeskyPivoted (#36002)

* add issuccess for CholeskyPivoted * add tests, NEWS and compat
JuliaLang · May 24, 2020 · 1747eac · 1747eac
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Showing 4 changed files with 7 additions and 2 deletions.
diff --git a/NEWS.md b/NEWS.md
@@ -47,7 +47,7 @@ Standard library changes
 * All `AbstractUnitRange{<:Integer}`s now work with `SubString`, `view`, `@view` and `@views` on strings ([#35879]).
 
 #### LinearAlgebra
-
+* New method `LinearAlgebra.issuccess(::CholeskyPivoted)` for checking whether pivoted Cholesky factorization was successful ([#36002]).
 
 #### Markdown
 

diff --git a/stdlib/LinearAlgebra/src/cholesky.jl b/stdlib/LinearAlgebra/src/cholesky.jl
@@ -447,7 +447,7 @@ end
 Base.propertynames(F::CholeskyPivoted, private::Bool=false) =
  (:U, :L, :p, :P, (private ? fieldnames(typeof(F)) : ())...)
 
-issuccess(C::Cholesky) = C.info == 0
+issuccess(C::Union{Cholesky,CholeskyPivoted}) = C.info == 0
 
 function show(io::IO, mime::MIME{Symbol("text/plain")}, C::Cholesky{<:Any,<:AbstractMatrix})
  if issuccess(C)

diff --git a/stdlib/LinearAlgebra/src/factorization.jl b/stdlib/LinearAlgebra/src/factorization.jl
@@ -25,6 +25,9 @@ checknonsingular(info) = checknonsingular(info, Val{true}())
 
 Test that a factorization of a matrix succeeded.
 
+!!! compat "Julia 1.6"
+ `issuccess(::CholeskyPivoted)` requires Julia 1.6 or later.
+
 ```jldoctest
 julia> F = cholesky([1 0; 0 1]);
 

diff --git a/stdlib/LinearAlgebra/test/cholesky.jl b/stdlib/LinearAlgebra/test/cholesky.jl
@@ -266,6 +266,8 @@ end
  @test_throws RankDeficientException cholesky!(copy(M), Val(true))
  @test_throws RankDeficientException cholesky(M, Val(true); check = true)
  @test_throws RankDeficientException cholesky!(copy(M), Val(true); check = true)
+ @test !LinearAlgebra.issuccess(cholesky(M, Val(true); check = false))
+ @test !LinearAlgebra.issuccess(cholesky!(copy(M), Val(true); check = false))
  C = cholesky(M, Val(true); check = false)
  @test_throws RankDeficientException chkfullrank(C)
  C = cholesky!(copy(M), Val(true); check = false)