From 769c62dfa5dc1c7d09cbb836f2f6842d57effcc6 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Fri, 10 Oct 2025 20:20:21 +0100
Subject: [PATCH 1/4] Update jacobi.jl

---
 src/classical/jacobi.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/classical/jacobi.jl b/src/classical/jacobi.jl
index 022e3a2..bb26390 100644
--- a/src/classical/jacobi.jl
+++ b/src/classical/jacobi.jl
@@ -635,6 +635,6 @@ end
 # sum
 ###
 
-_sum(P::AbstractJacobi{T}, dims) where T = 2 * (Legendre{T}() \ P)[1:1,:]
+_sum(P::AbstractJacobi{T}, dims::Int) where T = 2 * (Legendre{T}() \ P)[1:1,:]
 
 

From cdc923b43881ab102321db6c4d828cb60494b63c Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Fri, 10 Oct 2025 22:26:22 +0100
Subject: [PATCH 2/4] more overloads

---
 src/classical/chebyshev.jl | 8 ++++----
 src/classical/legendre.jl  | 2 +-
 src/interlace.jl           | 2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/classical/chebyshev.jl b/src/classical/chebyshev.jl
index 90a82d3..68806b2 100644
--- a/src/classical/chebyshev.jl
+++ b/src/classical/chebyshev.jl
@@ -296,24 +296,24 @@ end
 # sum
 ####
 
-function _sum(::Weighted{T,<:ChebyshevU}, dims) where T
+function _sum(::Weighted{T,<:ChebyshevU}, dims::Int) where T
     @assert dims == 1
     Hcat(convert(T, π)/2, Zeros{T}(1,∞))
 end
 
 # Same normalization for T,V,W
-function _sum(::Weighted{T,<:Chebyshev}, dims) where T
+function _sum(::Weighted{T,<:Chebyshev}, dims::Int) where T
     @assert dims == 1
     Hcat(convert(T, π), Zeros{T}(1,∞))
 end
 
-function _cumsum(T::ChebyshevT{V}, dims) where V
+function _cumsum(T::ChebyshevT{V}, dims::Int) where V
     @assert dims == 1
     Σ = _BandedMatrix(Vcat(-one(V) ./ (-2:2:∞)', Zeros{V}(1,∞), Hcat(one(V), one(V) ./ (4:2:∞)')), ℵ₀, 0, 2)
     ApplyQuasiArray(*, T, Vcat((-1).^(0:∞)'* Σ, Σ))
 end
 
-function _cumsum(W::Weighted{V, ChebyshevT{V}}, dims) where V
+function _cumsum(W::Weighted{V, ChebyshevT{V}}, dims::Int) where V
     @assert dims == 1
     [cumsum(ChebyshevTWeight{V}()) Weighted(ChebyshevU{V}())] * Diagonal(Vcat(one(V), -inv.(one(V):∞)))
 end
diff --git a/src/classical/legendre.jl b/src/classical/legendre.jl
index ec4154f..2d56d30 100644
--- a/src/classical/legendre.jl
+++ b/src/classical/legendre.jl
@@ -254,7 +254,7 @@ end
 # sum
 ###
 
-function _sum(P::Legendre{T}, dims) where T
+function _sum(P::Legendre{T}, dims::Int) where T
     @assert dims == 1
     Hcat(convert(T, 2), Zeros{T}(1,∞))
 end
diff --git a/src/interlace.jl b/src/interlace.jl
index e72d254..b85f7b6 100644
--- a/src/interlace.jl
+++ b/src/interlace.jl
@@ -272,7 +272,7 @@ end
 # sum
 ###
 
-_sum(P::PiecewiseInterlace, dims) = BlockBroadcastArray(hcat, unitblocks.(_sum.(P.args, dims))...)
+_sum(P::PiecewiseInterlace, dims::Int) = BlockBroadcastArray(hcat, unitblocks.(_sum.(P.args, dims))...)
 
 # blockvector2vectortuple
 

From 8246067c7321a73d56a2f125ddd7c7a64af470f6 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Sun, 12 Oct 2025 20:42:02 +0100
Subject: [PATCH 3/4] _sum for ChebyshevT

---
 src/classical/chebyshev.jl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/classical/chebyshev.jl b/src/classical/chebyshev.jl
index 68806b2..5d4b479 100644
--- a/src/classical/chebyshev.jl
+++ b/src/classical/chebyshev.jl
@@ -302,7 +302,7 @@ function _sum(::Weighted{T,<:ChebyshevU}, dims::Int) where T
 end
 
 # Same normalization for T,V,W
-function _sum(::Weighted{T,<:Chebyshev}, dims::Int) where T
+function _sum(::Weighted{T,<:ChebyshevT}, dims::Int) where T
     @assert dims == 1
     Hcat(convert(T, π), Zeros{T}(1,∞))
 end
@@ -318,6 +318,11 @@ function _cumsum(W::Weighted{V, ChebyshevT{V}}, dims::Int) where V
     [cumsum(ChebyshevTWeight{V}()) Weighted(ChebyshevU{V}())] * Diagonal(Vcat(one(V), -inv.(one(V):∞)))
 end
 
+function _sum(::ChebyshevT{T}, dims::Int) where T
+    @assert dims == 1
+    permutedims(vec(Hcat(Vcat(2one(T), -(2one(T)) ./ ((3:2:∞) .* (1:2:∞))), Zeros{T}(∞))'))
+end 
+
 ####
 # algebra
 ####

From 5bbcb240a7dddd70b40426f840aed65fc2a7bf06 Mon Sep 17 00:00:00 2001
From: Sheehan Olver <solver@mac.com>
Date: Mon, 13 Oct 2025 11:26:37 +0100
Subject: [PATCH 4/4] add test

---
 Project.toml           | 2 +-
 test/test_interlace.jl | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index faafbac..7468c32 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "ClassicalOrthogonalPolynomials"
 uuid = "b30e2e7b-c4ee-47da-9d5f-2c5c27239acd"
 authors = ["Sheehan Olver <solver@mac.com>"]
-version = "0.15.6"
+version = "0.15.7"
 
 
 [deps]
diff --git a/test/test_interlace.jl b/test/test_interlace.jl
index 0658721..99c3966 100644
--- a/test/test_interlace.jl
+++ b/test/test_interlace.jl
@@ -16,6 +16,7 @@ import ClassicalOrthogonalPolynomials: PiecewiseInterlace, SetindexInterlace, pl
             @test u[-0.1] ≈ exp(-0.1)
             @test u[0.1] ≈ exp(0.1)
             @test u[0.] ≈ 2
+            @test sum(u) ≈ ℯ - ℯ^(-1)
         end
 
         @testset "two-interval ODE" begin