LAMMPS uses Int32, so need BLAS LP64 compatibility. Default to OpenBL…

…AS32_jll if LP64 library not available

Project.toml

@@ -7,12 +7,14 @@ version = "0.7.2"
 CEnum = "fa961155-64e5-5f13-b03f-caf6b980ea82"
 LAMMPS_jll = "5b3ab26d-9607-527c-88ea-8fe5ba57cafe"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
-Preferences = "21216c6a-2e73-6563-6e65-726566657250"
+LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 MPI = "da04e1cc-30fd-572f-bb4f-1f8673147195"
+OpenBLAS32_jll = "656ef2d0-ae68-5445-9ca0-591084a874a2"
+Preferences = "21216c6a-2e73-6563-6e65-726566657250"
 
 [compat]
 CEnum = "0.4, 0.5"
 LAMMPS_jll = "2.6.0"
-Preferences = "1"
 MPI = "0.20"
+Preferences = "1"
 julia = "1.10"

src/LAMMPS.jl

@@ -1,5 +1,8 @@
 module LAMMPS
 import MPI
+import LinearAlgebra
+import OpenBLAS32_jll
+
 include("api.jl")
 
 export LMP, command, create_atoms, get_natoms, extract_atom, extract_compute, extract_global,
@@ -84,6 +87,12 @@ const TAGINT = API.lammps_extract_setting(C_NULL, "tagint") == 4 ? Int32 : Int64
 const IMAGEINT = API.lammps_extract_setting(C_NULL, "imageint") == 4 ? Int32 : Int64
 
 function __init__()
+    # LAMMPS requires using LP64, default to OpenBLAS32 if not already available
+    config = LinearAlgebra.BLAS.lbt_get_config()
+    if !any(lib -> lib.interface == :lp64, config.loaded_libs)
+        LinearAlgebra.BLAS.lbt_forward(OpenBLAS32_jll.libopenblas_path)
+    end
+
     BIGINT != (API.lammps_extract_setting(C_NULL, "bigint") == 4 ? Int32 : Int64) &&
         error("The size of the LAMMPS integer type BIGINT has changed! To fix this, you need to manually invalidate the LAMMPS.jl cache.")
     TAGINT != (API.lammps_extract_setting(C_NULL, "tagint") == 4 ? Int32 : Int64) &&