copied over missing cluster_update!() function

Author: Atomyka

lib/BloqadeQMC/src/updates/cluster.jl

@@ -235,7 +235,7 @@ trialstate_weight_change(qmc_state::BinaryThermalState, lsize::Int, Ns::Int, i::
 
 #############################################################################
 
-# changed the function name below from cluster_update!() to generic_cluster_update!()
+# changed the function name below from cluster_update!() to generic_cluster_update!() in order to distinguish it from the other cluster_update function defined at the very bottom
 
 function generic_cluster_update!(rng::AbstractRNG, update_kernel!::Function, acceptance::Function, lsize::Int, qmc_state::BinaryQMCState, H::AbstractIsing, d::Diagnostics)
     Ns = nspins(H)
@@ -331,3 +331,13 @@ function generic_cluster_update!(rng::AbstractRNG, update_kernel!::Function, acc
 
     return lsize
 end
+
+# might put this cluster_update function in a more visible position somewhere
+
+function cluster_update!(rng, qmc_state, H::Hamiltonian, d::Diagnostics; p::Float64=0.0, kw...)
+    if rand(rng) < p
+        multibranch_update!(rng, qmc_state, H, d)
+    else
+        line_update!(rng, qmc_state, H, d)
+    end
+end

lib/BloqadeQMC/src/updates/mc_step.jl

@@ -2,6 +2,16 @@
 
 # mc_step from groundstate.jl
 
+# I am keeping this function name cluster_update!() to keep it separate from the generic_cluster_update() function in cluster.jl. Previously, the two functions had the same name.
+
+function cluster_update!(rng, qmc_state, H::Hamiltonian, d::Diagnostics; p::Float64=0.0, kw...)
+    if rand(rng) < p
+        multibranch_update!(rng, qmc_state, H, d)
+    else
+        line_update!(rng, qmc_state, H, d)
+    end
+end
+
 function mc_step!(f::Function, rng::AbstractRNG, qmc_state::BinaryGroundState, H::Hamiltonian, d::Diagnostics; kw...)
     full_diagonal_update!(rng, qmc_state, H, d)
     lsize = cluster_update!(rng, qmc_state, H, d; kw...)