Add missing file

Author: shinaoka

src/globalpivotfinder.jl

@@ -0,0 +1,58 @@
+
+"""
+Default implementation of global pivot finder that uses random search.
+"""
+struct DefaultGlobalPivotFinder <: AbstractGlobalPivotFinder
+    nsearch::Int
+    maxnglobalpivot::Int
+    tolmarginglobalsearch::Float64
+end
+
+# Constructor for backward compatibility
+function DefaultGlobalPivotFinder(;
+    nsearch::Int=5,
+    maxnglobalpivot::Int=5,
+    tolmarginglobalsearch::Float64=10.0
+)
+    return DefaultGlobalPivotFinder(nsearch, maxnglobalpivot, tolmarginglobalsearch)
+end
+
+"""
+Find global pivots where the interpolation error exceeds the tolerance.
+"""
+function (finder::AbstractGlobalPivotFinder)(
+    tci::TensorCI2{ValueType},
+    f,
+    abstol::Float64;
+    verbosity::Int=0
+)::Vector{MultiIndex} where {ValueType}
+    error("find_global_pivots not implemented for $(typeof(finder))")
+end
+
+# Default implementation using the existing searchglobalpivots
+function (finder::DefaultGlobalPivotFinder)(
+    tci::TensorCI2{ValueType},
+    f,
+    abstol::Float64;
+    verbosity::Int=0
+)::Vector{MultiIndex} where {ValueType}
+    return searchglobalpivots(
+        tci, f, finder.tolmarginglobalsearch * abstol,
+        verbosity=verbosity,
+        nsearch=finder.nsearch,
+        maxnglobalpivot=finder.maxnglobalpivot
+    )
+end
+
+# Helper function for backward compatibility
+function _create_default_finder(;
+    nsearch::Int=5,
+    maxnglobalpivot::Int=5,
+    tolmarginglobalsearch::Float64=10.0
+)
+    return DefaultGlobalPivotFinder(
+        nsearch=nsearch,
+        maxnglobalpivot=maxnglobalpivot,
+        tolmarginglobalsearch=tolmarginglobalsearch
+    )
+end