draft CUDA-callable version of Domain::unmap

src/KOKKOS/domain_kokkos.h

@@ -16,6 +16,7 @@
 
 #include "domain.h"
 #include "kokkos_type.h"
+#include "kokkos_few.h"
 
 namespace LAMMPS_NS {
 
@@ -54,6 +55,10 @@ class DomainKokkos : public Domain {
   KOKKOS_INLINE_FUNCTION
   void operator()(TagDomain_x2lamda, const int&) const;
 
+  static KOKKOS_INLINE_FUNCTION
+  Few<double,3> unmap(Few<double,3> prd, Few<double,6> h, int triclinic,
+      Few<double,3> x, imageint image);
+
  private:
   double lo[3],hi[3],period[3];
   int n_flip, m_flip, p_flip;
@@ -61,6 +66,26 @@ class DomainKokkos : public Domain {
   ArrayTypes<LMPDeviceType>::t_imageint_1d image;
 };
 
+KOKKOS_INLINE_FUNCTION
+Few<double,3> DomainKokkos::unmap(Few<double,3> prd, Few<double,6> h,
+    int triclinic, Few<double,3> x, imageint image)
+{
+  int xbox = (image & IMGMASK) - IMGMAX;
+  int ybox = (image >> IMGBITS & IMGMASK) - IMGMAX;
+  int zbox = (image >> IMG2BITS) - IMGMAX;
+  Few<double,3> y;
+  if (triclinic == 0) {
+    y[0] = x[0] + xbox*prd[0];
+    y[1] = x[1] + ybox*prd[1];
+    y[2] = x[2] + zbox*prd[2];
+  } else {
+    y[0] = x[0] + h[0]*xbox + h[5]*ybox + h[4]*zbox;
+    y[1] = x[1] + h[1]*ybox + h[3]*zbox;
+    y[2] = x[2] + h[2]*zbox;
+  }
+  return y;
+}
+
 }
 
 #endif