Allow set_onsite_coupling! with zero

SunnySuite · Jul 30, 2023 · bd8ae6e · bd8ae6e
1 parent 1888468
commit bd8ae6e
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Showing 2 changed files with 13 additions and 9 deletions.
diff --git a/src/System/OnsiteCoupling.jl b/src/System/OnsiteCoupling.jl
@@ -130,6 +130,7 @@ See also [`spin_operators`](@ref).
 """
 function set_onsite_coupling!(sys::System{N}, op::Matrix{ComplexF64}, i::Int) where N
     is_homogeneous(sys) || error("Use `set_onsite_coupling_at!` for an inhomogeneous system.")
+    ints = interactions_homog(sys)
 
     # If `sys` has been reshaped, then operate first on `sys.origin`, which
     # contains full symmetry information.
@@ -139,18 +140,14 @@ function set_onsite_coupling!(sys::System{N}, op::Matrix{ComplexF64}, i::Int) wh
         return
     end
 
-    ints = interactions_homog(sys)
-
-    iszero(op) && return 
+    (1 <= i <= natoms(sys.crystal)) || error("Atom index $i is out of range.")
 
     if !is_anisotropy_valid(sys.crystal, i, op)
         @error """Symmetry-violating anisotropy: $op.
                   Use `print_site(crystal, $i)` for more information."""
         error("Invalid anisotropy.")
     end
 
-    (1 <= i <= natoms(sys.crystal)) || error("Atom index $i is out of range.")
-
     if !iszero(ints[i].onsite)
         warn_coupling_override("Overriding anisotropy for atom $i.")
     end

diff --git a/src/System/PairExchange.jl b/src/System/PairExchange.jl
@@ -31,10 +31,17 @@ end
 
 # Internal function only
 function push_coupling!(couplings, bond, bilin, biquad)
-    isculled = bond_parity(bond)
+    # Remove previous coupling on this bond
     filter!(c -> c.bond != bond, couplings)
+
+    # If the new coupling is exactly zero, return early
+    iszero(bilin) && iszero(biquad) && return
+
+    # Otherwise, add the new coupling to the list
+    isculled = bond_parity(bond)
     push!(couplings, PairCoupling(isculled, bond, bilin, biquad))
     sort!(couplings, by=c->c.isculled)
+
     return
 end
 
@@ -75,6 +82,9 @@ set_exchange!(sys, J2, bond)
 ```
 """
 function set_exchange!(sys::System{N}, J, bond::Bond; biquad=0.) where N
+    is_homogeneous(sys) || error("Use `set_exchange_at!` for an inhomogeneous system.")
+    ints = interactions_homog(sys)
+
     # If `sys` has been reshaped, then operate first on `sys.origin`, which
     # contains full symmetry information.
     if !isnothing(sys.origin)
@@ -85,9 +95,6 @@ function set_exchange!(sys::System{N}, J, bond::Bond; biquad=0.) where N
 
     validate_bond(sys.crystal, bond)
 
-    is_homogeneous(sys) || error("Use `set_exchange_at!` for an inhomogeneous system.")
-    ints = interactions_homog(sys)
-
     J = to_float_or_mat3(J)
 
     # Verify that exchange is symmetry-consistent