From 8c9d038818d01c024ab5eb0a0f51e7df8bb67434 Mon Sep 17 00:00:00 2001
From: droodman <droodman@gmail.com>
Date: Tue, 2 Apr 2024 22:19:05 -0400
Subject: [PATCH 1/3] Add drop_singletons option to partial_out()

---
 .gitignore         | 4 ++++
 src/partial_out.jl | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index a2f5fc4..de0d8cf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,7 @@
 
 benchmark/.sublime2Terminal.jl
 .vscode/settings.json
+Manifest.toml
+debug/debug.jl
+debug/pseudoreg.csv
+debug/repl.do
diff --git a/src/partial_out.jl b/src/partial_out.jl
index 30f866c..c4b7202 100644
--- a/src/partial_out.jl
+++ b/src/partial_out.jl
@@ -10,6 +10,7 @@ Partial out variables in a Dataframe
 * `double_precision::Bool`: Should the demeaning operation use Float64 rather than Float32? Default to true.
 * `tol::Real`: Tolerance
 * `align::Bool`: Should the returned DataFrame align with the original DataFrame in case of missing values? Default to true.
+* `drop_singletons::Bool=false`: Should singletons be dropped?
 
 ### Returns
 * `::DataFrame`: a dataframe with as many columns as there are dependent variables and as many rows as the original dataframe.
@@ -40,7 +41,8 @@ function partial_out(
     @nospecialize(method::Symbol = :cpu),
     @nospecialize(double_precision::Bool = true),
     @nospecialize(tol::Real = double_precision ? 1e-8 : 1e-6),
-    @nospecialize(align = true))
+    @nospecialize(align = true),
+    @nospecialize(drop_singletons = false))
 
     if  (ConstantTerm(0) ∉ eachterm(f.rhs)) & (ConstantTerm(1) ∉ eachterm(f.rhs))
         f = FormulaTerm(f.lhs, tuple(ConstantTerm(1), eachterm(f.rhs)...))
@@ -67,6 +69,7 @@ function partial_out(
     fes, ids, ids_fes = parse_fixedeffect(df, formula_fes)
     has_fes = !isempty(fes)
 
+    drop_singletons && drop_singletons!(esample, fes, Threads.nthreads())
 
     nobs = sum(esample)
     (nobs > 0) || throw("sample is empty")

From 563c32d36dffb4038dd3bb7ed628938a0ed4905b Mon Sep 17 00:00:00 2001
From: droodman <droodman@gmail.com>
Date: Tue, 2 Apr 2024 22:20:21 -0400
Subject: [PATCH 2/3] Update .gitignore

---
 .gitignore | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/.gitignore b/.gitignore
index de0d8cf..a2f5fc4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,7 +1,3 @@
 
 benchmark/.sublime2Terminal.jl
 .vscode/settings.json
-Manifest.toml
-debug/debug.jl
-debug/pseudoreg.csv
-debug/repl.do

From 2f9dd38d446546ba368ade57a0e4afec36cf6e54 Mon Sep 17 00:00:00 2001
From: droodman <droodman@gmail.com>
Date: Wed, 3 Apr 2024 17:03:36 -0400
Subject: [PATCH 3/3] Add dof_fes return value to partial_out()

---
 src/partial_out.jl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/partial_out.jl b/src/partial_out.jl
index c4b7202..9e94bfc 100644
--- a/src/partial_out.jl
+++ b/src/partial_out.jl
@@ -138,6 +138,8 @@ function partial_out(
         residuals .= residuals .+ m
     end
 
+    dof_fes = mapreduce(nunique, +, fes, init=0)
+
     # Return a dataframe
     out = DataFrame()
     j = 0
@@ -151,5 +153,5 @@ function partial_out(
             out[!, Symbol(y)] = residuals[:, j]
         end
     end
-    return out, esample, iterations, convergeds
+    return out, esample, iterations, convergeds, dof_fes
 end