Merge pull request #399 from JuliaArrays/linearalgebra_instance

complete the linear algebra instance functions for the main factorizations

Author: ChrisRackauckas

Project.toml

@@ -1,6 +1,6 @@
 name = "ArrayInterface"
 uuid = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
-version = "7.2.1"
+version = "7.3.0"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

docs/src/index.md

@@ -17,7 +17,7 @@ ArrayInterface.jl uses extension packages in order to add support for popular li
 
 ## StaticArrayInterface.jl
 
-If one is looking for an interface which includes functionality for statically-computed values, see 
+If one is looking for an interface which includes functionality for statically-computed values, see
 [StaticArrayInterface.jl](https://github.com/JuliaArrays/StaticArrayInterface.jl).
 This was separated from ArrayInterface.jl because it includes a lot of functionality that does not give substantive improvements
 to the interface, and is likely to be deprecated in the near future as the compiler matures to automate a lot of its optimizations.
@@ -44,7 +44,6 @@ ArrayInterface.isstructured
 ArrayInterface.has_sparsestruct
 ArrayInterface.ndims_index
 ArrayInterface.ndims_shape
-
 ```
 
 ### Functions
@@ -57,6 +56,8 @@ ArrayInterface.buffer
 ArrayInterface.findstructralnz
 ArrayInterface.flatten_tuples
 ArrayInterface.lu_instance
+ArrayInterface.qr_instance
+ArrayInterface.svd_instance
 ArrayInterface.map_tuple_type
 ArrayInterface.matrix_colors
 ArrayInterface.issingular
@@ -74,4 +75,4 @@ ArrayInterface.undefmatrix
 ArrayInterface.ArrayIndex
 ArrayInterface.GetIndex
 ArrayInterface.SetIndex!
-```
+```

src/ArrayInterface.jl

@@ -482,6 +482,59 @@ Returns the number.
 """
 lu_instance(a::Any) = lu(a, check = false)
 
+"""
+  qr_instance(A) -> qr_factorization_instance
+
+Returns an instance of the QR factorization object with the correct type
+cheaply.
+"""
+function qr_instance(A::Matrix{T}) where {T}
+    LinearAlgebra.QRCompactWYQ(zeros(T,0,0),zeros(T,0,0))
+end
+
+# Could be optimized but this should work for any real case.
+function qr_instance(jac_prototype::SparseMatrixCSC)
+    qr(sparse(rand(1,1)), check = false)
+end
+
+"""
+  qr_instance(a::Number) -> a
+
+Returns the number.
+"""
+qr_instance(a::Number) = a
+
+"""
+    qr_instance(a::Any) -> qr(a, check=false)
+
+Returns the number.
+"""
+qr_instance(a::Any) = qr(a, check = false)
+
+"""
+  svd_instance(A) -> qr_factorization_instance
+
+Returns an instance of the SVD factorization object with the correct type
+cheaply.
+"""
+function svd_instance(A::Matrix{T}) where {T}
+    LinearAlgebra.SVD(zeros(T,0,0),zeros(T,0),zeros(T,0,0))
+end
+
+"""
+  svd_instance(a::Number) -> a
+
+Returns the number.
+"""
+svd_instance(a::Number) = a
+
+"""
+    svd_instance(a::Any) -> qr(a, check=false)
+
+Returns the number.
+"""
+svd_instance(a::Any) = svd(a, check = false)
+
 """
     safevec(v)