From 4ec94c97879aafef15f7663135745e4ba61e62cf Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Mon, 17 May 2021 00:15:33 +0200
Subject: Extract first public LiterateLB version

---
 tangle/LLBM/sdf_boundary.h | 114 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 tangle/LLBM/sdf_boundary.h

(limited to 'tangle/LLBM/sdf_boundary.h')

diff --git a/tangle/LLBM/sdf_boundary.h b/tangle/LLBM/sdf_boundary.h
new file mode 100644
index 0000000..f91480e
--- /dev/null
+++ b/tangle/LLBM/sdf_boundary.h
@@ -0,0 +1,114 @@
+#pragma once
+#include <LLBM/memory.h>
+#include <LLBM/materials.h>
+#include <LLBM/kernel/bouzidi.h>
+#include <iostream>
+
+template <typename DESCRIPTOR, typename T, typename S, typename SDF>
+class SignedDistanceBoundary {
+private:
+const descriptor::Cuboid<DESCRIPTOR> _cuboid;
+const std::size_t _count;
+
+SharedVector<std::size_t> _boundary;
+SharedVector<std::size_t> _fluid;
+SharedVector<std::size_t> _solid;
+SharedVector<S> _distance;
+SharedVector<S> _correction;
+SharedVector<S> _factor;
+SharedVector<pop_index_t> _missing;
+
+void set(std::size_t index, std::size_t iCell, pop_index_t iPop, S dist) {
+  pop_index_t jPop = descriptor::opposite<DESCRIPTOR>(iPop);
+  const std::size_t jPopCell = descriptor::neighbor<DESCRIPTOR>(_cuboid, iCell, jPop);
+  const std::size_t iPopCell = descriptor::neighbor<DESCRIPTOR>(_cuboid, iCell, iPop);
+
+  _boundary[index] = iCell;
+  _solid[index] = jPopCell;
+  _distance[index] = dist;
+  _correction[index] = 0;
+  _missing[index] = iPop;
+
+  T q = dist / descriptor::velocity_length<DESCRIPTOR>(iPop);
+  if (q > 0.5) {
+    _fluid[index] = iCell;
+    _factor[index] = 1 / (2*q);
+  } else {
+    _fluid[index] = iPopCell;
+    _factor[index] = 2*q;
+  }
+}
+
+void syncDeviceFromHost() {
+  _boundary.syncDeviceFromHost();
+  _fluid.syncDeviceFromHost();
+  _solid.syncDeviceFromHost();
+  _distance.syncDeviceFromHost();
+  _correction.syncDeviceFromHost();
+  _factor.syncDeviceFromHost();
+  _missing.syncDeviceFromHost();
+}
+
+public:
+SignedDistanceBoundary(Lattice<DESCRIPTOR,T,S>&, CellMaterials<DESCRIPTOR>& materials, SDF geometry, int bulk, int solid):
+  _cuboid(materials.cuboid()),
+  _count(materials.get_link_count(bulk, solid)),
+  _boundary(_count),
+  _fluid(_count),
+  _solid(_count),
+  _distance(_count),
+  _correction(_count),
+  _factor(_count),
+  _missing(_count)
+{
+  std::size_t index = 0;
+  materials.for_links(bulk, solid, [&](std::size_t iCell, pop_index_t iPop) {
+    auto p         = gidInverseSmooth(_cuboid, iCell);
+    auto direction = normalize(descriptor::velocity<DESCRIPTOR>(iPop));
+    float length   = descriptor::velocity_length<DESCRIPTOR>(iPop);
+    float distance = approximateDistance(geometry, p, direction, 0, length);
+    if (distance == 0.f || distance > length) {
+      std::cout << "Bogus distance d=" << distance << " at cell " << iCell
+                << " in direction " << std::to_string(iPop) << std::endl;
+    }
+    set(index++, iCell, descriptor::opposite<DESCRIPTOR>(iPop), distance);
+  });
+  syncDeviceFromHost();
+}
+
+template <typename VELOCITY>
+void setVelocity(VELOCITY field) {
+  for (std::size_t index=0; index < _count; ++index) {
+    pop_index_t jPop = descriptor::opposite<DESCRIPTOR>(_missing[index]);
+    auto direction = normalize(descriptor::velocity<DESCRIPTOR>(jPop));
+    float length = descriptor::velocity_length<DESCRIPTOR>(jPop);
+    auto p = descriptor::gidInverseSmooth(_cuboid, _boundary[index]);
+    auto u_w = field(p + _distance[index] * direction);
+    _correction[index] = 2*3*descriptor::weight<DESCRIPTOR>(jPop)
+                       * dot(u_w, descriptor::velocity<DESCRIPTOR>(jPop));
+    if (_distance[index] / length > 0.5) {
+      _correction[index] *= _factor[index];
+    }
+  }
+  _correction.syncDeviceFromHost();
+}
+
+std::size_t getCount() const {
+  return _count;
+}
+
+BouzidiConfig<S> getConfig() {
+  return BouzidiConfig<S>{
+    _boundary.device(),
+    _solid.device(),
+    _fluid.device(),
+    _factor.device(),
+    _correction.device(),
+    _missing.device()
+  };
+}
+
+};
+
+template <typename DESCRIPTOR, typename T, typename S, typename SDF>
+SignedDistanceBoundary(Lattice<DESCRIPTOR,T,S>&, CellMaterials<DESCRIPTOR>&, SDF, int, int) -> SignedDistanceBoundary<DESCRIPTOR,T,S,SDF>;
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