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   "source": [
    "# Tutorial 08: Defining micromagnetic system\n",
    "\n",
    "> Interactive online tutorial:\n",
    "> [![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/ubermag/micromagneticmodel/master?filepath=docs%2Fipynb%2Findex.ipynb)\n",
    "\n",
    "A micromagnetic system is the main entity of the micromagnetic model. It consists of three main components:\n",
    "- Hamiltonian\n",
    "- Dynamics equation\n",
    "- Magnetisation configuration\n",
    "\n",
    "In this tutorial, we will assemble a micromagnetic system, which can then be \"driven\" using different drivers."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import micromagneticmodel as mm"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Firstly, we create a Hamiltonian:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [],
   "source": [
    "hamiltonian = mm.Exchange(A=1e-11) + mm.Zeeman(H=(1e6, 0, 0))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Next, we define the dynamics equation."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "dynamics = mm.Precession(gamma=mm.consts.gamma0) + mm.Damping(alpha=0.1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Finally, magnetisation configuration must be defined as `discretisationfield.Field`."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "import discretisedfield as df\n",
    "\n",
    "p1 = (0, 0, 0)\n",
    "p2 = (10e-9, 10e-9, 10e-9)\n",
    "n = (5, 5, 5)\n",
    "Ms = 1e6\n",
    "mesh = df.Mesh(p1=p1, p2=p2, n=n)\n",
    "m = df.Field(mesh, dim=3, value=(0, 0, 1), norm=Ms)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Using these three parameters we can assemble the system object."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "system = mm.System(hamiltonian=hamiltonian, dynamics=dynamics, m=m, name='mysystem')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We can now check some basics properties of the assembled system."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "System(name='mysystem')"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "system"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/latex": [
       "$w=A (\\nabla \\mathbf{m})^{2}-\\mu_{0}M_\\text{s} \\mathbf{m} \\cdot \\mathbf{H}$"
      ],
      "text/plain": [
       "Exchange(A=1e-11, name='exchange') + Zeeman(H=(1000000.0, 0, 0), name='zeeman')"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "system.hamiltonian"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/latex": [
       "$\\frac{\\partial \\mathbf{m}}{\\partial t}=-\\gamma_{0}^{*} \\mathbf{m} \\times \\mathbf{H}_\\text{eff}+\\alpha \\mathbf{m} \\times\\frac{\\partial \\mathbf{m}}{\\partial t}$"
      ],
      "text/plain": [
       "Precession(gamma=221276.14872118403, name='precession') + Damping(alpha=0.1, name='damping')"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "system.dynamics"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "application/vnd.jupyter.widget-view+json": {
       "model_id": "c97ecd38f6644bd19db56735776df466",
       "version_major": 2,
       "version_minor": 0
      },
      "text/plain": [
       "Output()"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "# NBVAL_IGNORE_OUTPUT\n",
    "system.m.k3d_vectors()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Other\n",
    "\n",
    "Full description of all existing descriptors can be found in the [API Reference](https://micromagneticmodel.readthedocs.io/en/latest/?badge=latest)."
   ]
  }
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