mirror of
https://gitlab.kitware.com/vtk/vtk-m
synced 2024-09-08 13:23:51 +00:00
26ea2ab420
The circular dependency came from UnknownArrayHandle.h needing VTKmDefaultTypes.h, which needed all the cell set types. Some of those cell sets used ArrayCopy in templated functions. Changed those functions to directly deep copy the ArrayHandle.
124 lines
4.2 KiB
C++
124 lines
4.2 KiB
C++
//
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// Created by ollie on 7/8/20.
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//
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//============================================================================
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// Copyright (c) Kitware, Inc.
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// All rights reserved.
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// See LICENSE.txt for details.
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//
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// This software is distributed WITHOUT ANY WARRANTY; without even
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// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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// PURPOSE. See the above copyright notice for more information.
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//============================================================================
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/// Simulation of ferromagnetism using the Ising Model
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/// Reference: Computational Physics 2nd Edition, Nicholas Giordano & Hisao Nakanishi
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#include <iomanip>
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#include <vtkm/cont/ArrayCopy.h>
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#include <vtkm/cont/ArrayHandleRandomUniformReal.h>
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#include <vtkm/cont/DataSet.h>
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#include <vtkm/cont/DataSetBuilderUniform.h>
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#include <vtkm/cont/Initialize.h>
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#include <vtkm/rendering/CanvasRayTracer.h>
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#include <vtkm/rendering/MapperRayTracer.h>
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#include <vtkm/rendering/Scene.h>
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#include <vtkm/rendering/View2D.h>
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#include <vtkm/worklet/WorkletCellNeighborhood.h>
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struct UpDown
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{
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VTKM_EXEC_CONT vtkm::Float32 operator()(vtkm::Float32 p) const { return p > 0.5 ? 1.0f : -1.0f; }
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};
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vtkm::cont::DataSet SpinField(vtkm::Id2 dims)
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{
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auto result =
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vtkm::cont::DataSetBuilderUniform::Create(dims, vtkm::Vec2f{ 0, 0 }, vtkm::Vec2f{ 1, 1 });
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vtkm::cont::ArrayHandle<vtkm::Float32> spins;
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vtkm::cont::ArrayCopy(
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vtkm::cont::make_ArrayHandleTransform(
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vtkm::cont::ArrayHandleRandomUniformReal<vtkm::Float32>(result.GetNumberOfCells()), UpDown{}),
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spins);
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result.AddCellField("spins", spins);
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return result;
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}
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struct UpdateSpins : public vtkm::worklet::WorkletCellNeighborhood
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{
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using ControlSignature = void(CellSetIn,
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FieldInNeighborhood prevspin,
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FieldIn prob,
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FieldOut spin);
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using ExecutionSignature = void(_2, _3, _4);
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template <typename NeighIn>
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VTKM_EXEC_CONT void operator()(const NeighIn& prevspin,
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vtkm::Float32 p,
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vtkm::Float32& spin) const
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{
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// TODO: what is the real value and unit of the change constant J and Boltzmann constant kB?
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const vtkm::Float32 J = 1.f;
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const vtkm::Float32 kB = 1.f;
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// TODO: temperature in Kelvin
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const vtkm::Float32 T = 5.f;
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const auto mySpin = prevspin.Get(0, 0, 0);
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// 1. Calculate the energy of flipping, E_flip
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vtkm::Float32 E_flip = J * mySpin *
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(prevspin.Get(-1, -1, 0) + prevspin.Get(-1, 0, 0) + prevspin.Get(-1, 1, 0) +
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prevspin.Get(0, -1, 0) + prevspin.Get(0, 1, 0) + prevspin.Get(1, -1, 0) +
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prevspin.Get(1, 0, 0) + prevspin.Get(1, 1, 0));
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if (E_flip <= 0)
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{
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// 2. If E_flip <= 0, just flip the spin
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spin = -1.f * mySpin;
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}
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else
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{
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// 3. otherwise, flip the spin if the Boltzmann factor exp(-E_flip/kB*T) is larger than the
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// uniform real random number p.
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if (p <= vtkm::Exp(-E_flip / (kB * T)))
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spin = -1.f * mySpin;
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else
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spin = mySpin;
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}
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}
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};
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int main(int argc, char** argv)
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{
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auto opts =
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vtkm::cont::InitializeOptions::DefaultAnyDevice | vtkm::cont::InitializeOptions::Strict;
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vtkm::cont::Initialize(argc, argv, opts);
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auto dataSet = SpinField({ 5, 5 });
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vtkm::cont::ArrayHandle<vtkm::Float32> spins;
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dataSet.GetCellField("spins").GetData().AsArrayHandle(spins);
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vtkm::rendering::Scene scene;
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vtkm::rendering::Actor actor(dataSet.GetCellSet(),
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dataSet.GetCoordinateSystem(),
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dataSet.GetCellField("spins"),
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vtkm::cont::ColorTable("Cool To Warm"));
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scene.AddActor(actor);
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vtkm::rendering::CanvasRayTracer canvas(1024, 1024);
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vtkm::rendering::MapperRayTracer mapper;
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mapper.SetShadingOn(false);
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vtkm::rendering::View2D view(scene, mapper, canvas);
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view.Paint();
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view.SaveAs("spin0.png");
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vtkm::cont::Invoker invoker;
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for (vtkm::UInt32 i = 1; i < 10; ++i)
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{
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vtkm::cont::ArrayHandleRandomUniformReal<vtkm::Float32> prob(dataSet.GetNumberOfCells(), { i });
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invoker(UpdateSpins{}, dataSet.GetCellSet(), spins, prob, spins);
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view.Paint();
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view.SaveAs("spin" + std::to_string(i) + ".png");
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}
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}
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