{
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   "source": [
    "<div class=\"contentcontainer med left\" style=\"margin-left: -50px;\">\n",
    "<dl class=\"dl-horizontal\">\n",
    "  <dt>Title</dt> <dd> ErrorBars Element</dd>\n",
    "  <dt>Dependencies</dt> <dd>Bokeh</dd>\n",
    "  <dt>Backends</dt>\n",
    "    <dd><a href='./ErrorBars.ipynb'>Bokeh</a></dd>\n",
    "    <dd><a href='../matplotlib/ErrorBars.ipynb'>Matplotlib</a></dd>\n",
    "    <dd><a href='../plotly/ErrorBars.ipynb'>Plotly</a></dd>\n",
    "</dl>\n",
    "</div>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import holoviews as hv\n",
    "hv.extension('bokeh')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "``ErrorBars`` provide a visual indicator for the variability of the plotted data on a graph. They are usually applied on top of other plots such as scatter, curve or bar plots to indicate the variability in each sample. \n",
    "\n",
    "``ErrorBars`` may be used to represent symmetric error or asymmetric error. An ``ErrorBars`` Element must have one key dimensions representing the samples along the x-axis and two or three value dimensions representing the value of the sample and positive and negative error values associated with that sample or x-axis. See the [Tabular Datasets](../../../user_guide/08-Tabular_Datasets.ipynb) user guide for supported data formats, which include arrays, pandas dataframes and dictionaries of arrays."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Symmetric error\n",
    "\n",
    "By default the ``ErrorBars`` Element accepts x- and y-coordinates along with a symmetric error value along y-axis:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "np.random.seed(7)\n",
    "errors = [(0.1*i, np.sin(0.1*i), np.random.rand()/2) for i in np.linspace(0, 100, 11)]\n",
    "hv.Curve(errors) * hv.ErrorBars(errors)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Asymmetric error"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "``ErrorBars`` is a set of x-/y-coordinates with associated error values along y-axis.  Error values may be either symmetric or asymmetric, and thus can be supplied as an Nx3 or Nx4 array (or any of the alternative constructors Chart Elements allow)."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "errors = [(0.1*i, np.sin(0.1*i), np.random.rand()/2, np.random.rand()/4) for i in np.linspace(0, 100, 11)]\n",
    "hv.Curve(errors) * hv.ErrorBars(errors, vdims=['y', 'yerrneg', 'yerrpos'])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Errors along x-axis"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "``ErrorBars`` can be a set of a set of x-/y-coordinates with associated error values along x-axis. The parameter `horizontal`, when set to `True`, will set supplied errors along x-axis instead of y-axis."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "errors = [(0.1*i, np.sin(0.1*i), np.random.rand()/2) for i in np.linspace(0, 100, 11)]\n",
    "hv.Curve(errors) * hv.ErrorBars(errors, horizontal=True)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "#### Errors along x and y axes"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Two `ErrorBars` with orthogonal errors can be composed together to give x and y errorbars"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "yerrors = [(0.1*i, np.sin(0.1*i), np.random.rand()/2, np.random.rand()/4) for i in np.linspace(0, 100, 11)]\n",
    "xerrors = [(0.1*i, np.sin(0.1*i), np.random.rand()/2, np.random.rand()/4) for i in np.linspace(0, 100, 11)]\n",
    "\n",
    "(hv.Curve(yerrors)\n",
    " * hv.ErrorBars(yerrors, vdims=['y', 'yerrneg', 'yerrpos'])\n",
    " * hv.ErrorBars(xerrors, vdims=['y', 'xerrneg', 'xerrpos'], horizontal=True)\n",
    ")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "For full documentation and the available style and plot options, use ``hv.help(hv.ErrorBars).``"
   ]
  }
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