From fbdcfb2f7255e0813fe373bf0f9455441f9395e5 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Mon, 10 May 2021 09:16:51 -0400
Subject: [PATCH] preliminary interface to detect whether a viable GPU is
 present

---
 lib/gpu/lal_device.cpp |  9 +++++++++
 src/info.cpp           | 12 ++++++++++++
 src/info.h             |  1 +
 3 files changed, 22 insertions(+)

diff --git a/lib/gpu/lal_device.cpp b/lib/gpu/lal_device.cpp
index 1c19cf9186..cd38e9d959 100644
--- a/lib/gpu/lal_device.cpp
+++ b/lib/gpu/lal_device.cpp
@@ -1026,6 +1026,15 @@ Device<PRECISION,ACC_PRECISION> global_device;
 }
 
 using namespace LAMMPS_AL;
+
+bool lmp_has_device()
+{
+  auto tmpgpu = new UCL_Device();
+  int num = tmpgpu->num_platforms();
+  delete tmpgpu;
+  return num > 0;
+}
+
 int lmp_init_device(MPI_Comm world, MPI_Comm replica, const int ngpu,
                     const int first_gpu_id, const int gpu_mode,
                     const double particle_split, const int t_per_atom,
diff --git a/src/info.cpp b/src/info.cpp
index 512858b9f2..a033d6608f 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -320,6 +320,7 @@ void Info::command(int narg, char **arg)
   if (flags & ACCELERATOR) {
     fmt::print(out,"\nAccelerator configuration:\n\n{}",
                get_accelerator_info());
+    fmt::print(out,"\nGPU present: {}\n",has_gpu_device() ? "yes" : "no");
   }
 
   if (flags & MEMORY) {
@@ -1139,6 +1140,17 @@ bool Info::has_package(const std::string &package_name) {
 
 #if defined(LMP_GPU)
 extern bool lmp_gpu_config(const std::string &, const std::string &);
+extern bool lmp_has_device();
+
+bool Info::has_gpu_device()
+{
+  return lmp_has_device();
+}
+#else
+bool Info::has_gpu_device()
+{
+  return false;
+}
 #endif
 
 #if defined(LMP_KOKKOS)
diff --git a/src/info.h b/src/info.h
index 9eb84d9312..ff649cc2bb 100644
--- a/src/info.h
+++ b/src/info.h
@@ -47,6 +47,7 @@ class Info : public Command {
   static bool has_accelerator_feature(const std::string &,
                                       const std::string &,
                                       const std::string &);
+  static bool has_gpu_device();
 
   static std::string get_os_info();
   static std::string get_compiler_info();