add DefaultAlgorithm

Author: lkdvos

src/MatrixAlgebraKit.jl

@@ -39,6 +39,7 @@ export LAPACK_HouseholderQR, LAPACK_HouseholderLQ, LAPACK_Simple, LAPACK_Expert,
 export GLA_HouseholderQR, GLA_QRIteration, GS_QRIteration
 export LQViaTransposedQR
 export PolarViaSVD, PolarNewton
+export DefaultAlgorithm
 export DiagonalAlgorithm
 export NativeBlocked
 export CUSOLVER_Simple, CUSOLVER_HouseholderQR, CUSOLVER_QRIteration, CUSOLVER_SVDPolar,

src/interface/decompositions.jl

@@ -304,6 +304,15 @@ until convergence up to tolerance `tol`.
 # =========================
 # Varia
 # =========================
+"""
+    DefaultAlgorithm(; kwargs...)
+
+Algorithm sentinel that resolves to the default algorithm for a given function and input
+type at call time. Any keyword arguments stored in the instance are forwarded at runtime
+to [`select_algorithm`](@ref).
+"""
+@algdef DefaultAlgorithm
+
 """
     DiagonalAlgorithm(; kwargs...)