fix flipped lower and upper in profile CI (#785)

* fix flipped lower and upper in profile CI

* news link

* thinko

* julia 1.8 compat

* remove debug lines

Author: palday

NEWS.md

@@ -1,3 +1,7 @@
+MixedModels v4.26.1 Release Notes
+==============================
+- lower and upper edges of profile confidence intervals for REML-fitted models are no longer flipped [#785]
+
 MixedModels v4.26.0 Release Notes
 ==============================
 - `issingular` now accepts comparison tolerances through the keyword arguments `atol` and `rtol`. [#783]
@@ -564,3 +568,4 @@ Package dependencies
 [#776]: https://github.com/JuliaStats/MixedModels.jl/issues/776
 [#778]: https://github.com/JuliaStats/MixedModels.jl/issues/778
 [#783]: https://github.com/JuliaStats/MixedModels.jl/issues/783
+[#785]: https://github.com/JuliaStats/MixedModels.jl/issues/785

Project.toml

@@ -1,7 +1,7 @@
 name = "MixedModels"
 uuid = "ff71e718-51f3-5ec2-a782-8ffcbfa3c316"
 author = ["Phillip Alday <[email protected]>", "Douglas Bates <[email protected]>", "Jose Bayoan Santiago Calderon <[email protected]>"]
-version = "4.26.0"
+version = "4.26.1"
 
 [deps]
 Arrow = "69666777-d1a9-59fb-9406-91d4454c9d45"

src/profile/profile.jl

@@ -73,12 +73,23 @@ function StatsAPI.confint(pr::MixedModelProfile; level::Real=0.95)
     cutoff = sqrt(quantile(Chisq(1), level))
     rev = pr.rev
     syms = sort!(collect(filter(k -> !startswith(string(k), 'θ'), keys(rev))))
-    return DictTable(;
+    dt = DictTable(;
         par=syms,
-        estimate=[rev[s](false) for s in syms],
+        estimate=[rev[s](0) for s in syms],
         lower=[rev[s](-cutoff) for s in syms],
         upper=[rev[s](cutoff) for s in syms],
     )
+
+    # XXX for reasons I don't understand, the reverse spline for REML-models
+    # is flipped for the fixed effects, even though the table of interpolation
+    # points isn't.
+    for i in keys(dt.lower)
+        if dt.lower[i] > dt.upper[i]
+            dt.lower[i], dt.upper[i] = dt.upper[i], dt.lower[i]
+        end
+    end
+
+    return dt
 end
 
 function Base.show(io::IO, mime::MIME"text/plain", pr::MixedModelProfile)

test/pls.jl

@@ -662,6 +662,12 @@ end
             [265.130, 13.576, 28.858, 37.718, 8.753];
             atol=1.e-3)
         @test first(only(filter(r -> r.p == :σ && iszero(r.ζ), pr.tbl)).σ) == last(models(:sleepstudy)).σ
+
+        @testset "REML" begin
+            m = refit!(deepcopy(last(models(:sleepstudy))); progress=false, REML=true)
+            ci = @suppress confint(profile(m))
+            @test all(splat(<), zip(ci.lower, ci.upper))
+        end
     end
     @testset "confint" begin
         ci = confint(last(models(:sleepstudy)))

test/runtests.jl

@@ -7,6 +7,8 @@ using Test
 import InteractiveUtils: versioninfo
 import LinearAlgebra: BLAS
 
+using Base: splat # necessary for Julia 1.8 compat
+
 # there seem to be processor-specific issues and knowing this is helpful
 @info sprint(versioninfo)
 @info BLAS.get_config()