bat · BJMCox · Sep 9, 2026 · Sep 9, 2026 · Sep 9, 2026 · Sep 9, 2026
diff --git a/Project.toml b/Project.toml
@@ -75,6 +75,7 @@ MGVI = "fdae7790-d271-4276-880d-f72bbddf129c"
 NestedSamplers = "41ceaf6f-1696-4a54-9b49-2e7a9ec3782e"
 Optim = "429524aa-4258-5aef-a3af-852621145aeb"
 OptimizationBase = "bca83a33-5cc9-4baa-983d-23429ab6bcbb"
+OptimizationLBFGSB = "22f7324a-a79d-40f2-bebe-3af60c77bd15"
 Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
 PropertyFunctions = "09e99361-2bb8-48a2-a80f-de58f0739eb4"
 PythonCall = "6099a3de-0909-46bc-b1f4-468b9a2dfc0d"
@@ -91,6 +92,7 @@ BATMGVIExt = "MGVI"
 BATNestedSamplersExt = "NestedSamplers"
 BATOptimExt = "Optim"
 BATOptimizationBaseExt = ["OptimizationBase"]
+BATOptimizationLBFGSBExt = "OptimizationLBFGSB"
 BATPlotsExt = "Plots"
 BATPropertyFunctionsExt = "PropertyFunctions"
 BATSliceSamplingExt = "SliceSampling"
@@ -147,6 +149,7 @@ NestedSamplers = "0.8, 0.9"
 OneTwoMany = "0.1.2"
 Optim = "1.12, 2"
 OptimizationBase = "3.3, 4, 5"
+OptimizationLBFGSB = "1.5"
 PDMats = "0.9, 0.10, 0.11"
 ParallelProcessingTools = "0.4"
 Parameters = "0.12, 0.13"

diff --git a/docs/make.jl b/docs/make.jl
@@ -42,6 +42,7 @@ makedocs(
         "Home" => "index.md",
         "Installation" => "installation.md",
         "List of algorithms" => "list_of_algorithms.md",
+        "Molewhacker importance sampling" => "molewhacker.md",
         "Tutorial" => "tutorial.md",
         "API Documentation" => "stable_api.md",
         "Plotting" => "plotting.md",

diff --git a/docs/src/experimental_api.md b/docs/src/experimental_api.md
@@ -37,6 +37,8 @@ EllipticalSliceMCMCSampling
 GridSampler
 HierarchicalDistribution
 PriorImportanceSampler
+MolewhackerRefit
+MolewhackerSampling
 ReactiveNestedSampling
 SliceMCMCSampling
 SobolSampler

diff --git a/docs/src/internal_api.md b/docs/src/internal_api.md
@@ -60,6 +60,7 @@ BAT.LogDVal
 BAT.MCMCSampleGenerator
 BAT.MCMCStepInfo
 BAT.MeasureLike
+BAT.MultiThreadedExec
 BAT.NoWhitening
 BAT.OnlineMvCov
 BAT.OnlineMvMean

diff --git a/docs/src/list_of_algorithms.md b/docs/src/list_of_algorithms.md
@@ -112,6 +112,22 @@ bat_sample(target, PriorImportanceSampler(nsamples=10^5))
 ```
 
 
+## Molewhacker importance sampler (experimental)
+
+BAT sampling algorithm type: [`MolewhackerSampling`](@ref)
+
+```julia
+import ForwardDiff, OptimizationLBFGSB
+context = BATContext(ad = ForwardDiff)
+bat_sample(target, MolewhackerSampling(nsamples = 10^4), context)
+```
+
+Fits a defensive Gaussian mixture with local Fisher geometry. Returns fresh
+importance samples from the fitted proposal. No MGVI dependency is required.
+See [Molewhacker importance sampling](molewhacker.md) for supported models,
+the sampling law, tuning, and diagnostics.
+
+
 ## Integration algorithms
 
 BAT function: [`bat_integrate`](@ref)

diff --git a/docs/src/molewhacker.md b/docs/src/molewhacker.md
diff --git a/ext/BATOptimizationLBFGSBExt.jl b/ext/BATOptimizationLBFGSBExt.jl
@@ -0,0 +1,18 @@
+# This file is a part of BAT.jl, licensed under the MIT License (MIT).
+
+module BATOptimizationLBFGSBExt
+
+using BAT
+import OptimizationLBFGSB
+
+BAT.pkgext(::Val{:OptimizationLBFGSB}) = BAT.PackageExtension{:OptimizationLBFGSB}()
+BAT.ext_default(::BAT.PackageExtension{:OptimizationLBFGSB}, ::Val{:LBFGSB_ALG}) = OptimizationLBFGSB.LBFGSB()
+
+# The Fortran backend requires Float64 input. The sampler converts fitted
+# centers back to the context precision before forming proposal geometry.
+function BAT._mw_mode(center::AbstractVector{Float32}, logtarget,
+    mode::BAT.OptimizationAlg{<:OptimizationLBFGSB.LBFGSB}, remaining, context)
+    return BAT._mw_mode(Float64.(center), logtarget, mode, remaining, context)
+end
+
+end