From 02fad62f8180ded4c36c3b174689577c29a7a93a Mon Sep 17 00:00:00 2001
From: Marek Kaluba <kalmar@amu.edu.pl>
Date: Mon, 13 Nov 2023 17:50:14 +0100
Subject: [PATCH] allow specifying index type for CachedExtensionHomomorphism

---
 src/ext_homomorphisms.jl   | 20 ++++++++++++++++++--
 test/action_permutation.jl | 11 +++++++++++
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/ext_homomorphisms.jl b/src/ext_homomorphisms.jl
index 0e8171d..f103534 100644
--- a/src/ext_homomorphisms.jl
+++ b/src/ext_homomorphisms.jl
@@ -78,12 +78,13 @@ StarAlgebras.basis(h::CachedExtensionHomomorphism) = basis(h.ehom)
 action(h::CachedExtensionHomomorphism) = action(h.ehom)
 
 function CachedExtensionHomomorphism(
+    ::Type{I},
     G::Group,
     action::Action,
     basis;
     precompute = false,
-)
-    hom = ExtensionHomomorphism(action, basis)
+) where {I}
+    hom = ExtensionHomomorphism(I, action, basis)
     S = typeof(induce(hom, one(G)))
     chom = CachedExtensionHomomorphism{eltype(G),S}(hom)
     @sync if precompute
@@ -96,6 +97,21 @@ function CachedExtensionHomomorphism(
     return chom
 end
 
+function CachedExtensionHomomorphism(
+    G::Group,
+    action::Action,
+    basis;
+    precompute = false,
+)
+    return CachedExtensionHomomorphism(
+        _int_type(ExtensionHomomorphism),
+        G,
+        action,
+        basis;
+        precompute = precompute,
+    )
+end
+
 function induce(ac::Action, chom::CachedExtensionHomomorphism, g::GroupElement)
     return _induce(ac, chom, g)
 end
diff --git a/test/action_permutation.jl b/test/action_permutation.jl
index 51aeed6..f80dec5 100644
--- a/test/action_permutation.jl
+++ b/test/action_permutation.jl
@@ -52,12 +52,23 @@ end
     action = OnLetters()
     tbl = SymbolicWedderburn.CharacterTable(Rational{Int}, G)
     ehom = SymbolicWedderburn.CachedExtensionHomomorphism(
+        Int32,
         G,
         action,
         words;
         precompute = true,
     )
     @test all(g ∈ keys(ehom.cache) for g in G) # we actually cached
+    @test typeof(SymbolicWedderburn.induce(ehom, one(G))) == Perm{Int32}
+
+    ehom = SymbolicWedderburn.CachedExtensionHomomorphism(
+        G,
+        action,
+        words;
+        precompute = true,
+    )
+    @test all(g ∈ keys(ehom.cache) for g in G) # we actually cached
+    @test typeof(SymbolicWedderburn.induce(ehom, one(G))) == Perm{UInt16}
 
     ψ = SymbolicWedderburn.action_character(ehom, tbl)
     @test SymbolicWedderburn.constituents(ψ) == [40, 22, 18]