Add data_and_model_to_datagroup method

docs/docs/tutorials/tutorial0_basics.ipynb

@@ -20,6 +20,7 @@
    "source": [
     "# Imports\n",
     "import pooch\n",
+    "import scipp as sc\n",
     "\n",
     "import easydynamics as edyn\n",
     "import easydynamics.sample_model as sm\n",
@@ -322,7 +323,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "print(f'The reduced chi-squared value for Q_index=5 is: {fit_result_all_Q[5].reduced_chi}')\n",
+    "print(f'The reduced chi-squared value for Q_index=5 is: {fit_result_all_Q[5].reduced_chi2}')\n",
     "\n",
     "print(f'The minimizer engine is: {fit_result_all_Q[5].minimizer_engine}')"
    ]
@@ -363,6 +364,25 @@
     "analysis.plot_parameters(names=['Gaussian area'])"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "d6e8ece6",
+   "metadata": {},
+   "source": [
+    "If you wish to customise the plot beyond what is immediately possible with EasyDynamics, you can get the data and model as a scipp datagroup. You may evaluate the model at different energies than the data like this."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3af8c1f1",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "energy = sc.linspace('energy', -3.5, 3.5, num=1001, unit='meV')\n",
+    "data_and_model = analysis.data_and_model_to_datagroup(energy=energy)"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "842c1f01",

docs/docs/tutorials/tutorial2_nanoparticles.ipynb

@@ -34,7 +34,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": null,
    "id": "bca91d3c",
    "metadata": {},
    "outputs": [],
@@ -70,7 +70,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": null,
    "id": "4fbb90da",
    "metadata": {},
    "outputs": [],
@@ -306,7 +306,7 @@
    "outputs": [],
    "source": [
     "analysis.fit()\n",
-    "analysis.plot_data_and_model(logy=True)"
+    "analysis.plot_data_and_model(logy=True, autoscale=False)"
    ]
   },
   {

src/easydynamics/analysis/analysis.py

@@ -285,25 +285,35 @@ def plot_data_and_model(
 
         import plopp as pp
 
+        data_and_model = self.data_and_model_to_datagroup(
+            energy=energy,
+            add_background=add_background,
+            include_components=plot_components,
+        )
+
         plot_kwargs_defaults = {
             'title': self.display_name,
-            'linestyle': {'Data': 'none', 'Model': '-'},
-            'marker': {'Data': 'o', 'Model': None},
-            'color': {'Data': 'black', 'Model': 'red'},
-            'markerfacecolor': {'Data': 'none', 'Model': 'none'},
+            'linestyle': {},
+            'marker': {},
+            'color': {},
+            'markerfacecolor': {},
             'keep': 'energy',
         }
-        data_and_model = {
-            'Data': self.experiment.binned_data,
-            'Model': self._create_model_array(energy=energy),
-        }
 
-        if plot_components:
-            components = self._create_components_dataset(
-                add_background=add_background, energy=energy
-            )
-            for key in components:
-                data_and_model[key] = components[key]
+        for key in data_and_model:
+            if key == 'Data':
+                plot_kwargs_defaults['linestyle'][key] = 'none'
+                plot_kwargs_defaults['marker'][key] = 'o'
+                plot_kwargs_defaults['color'][key] = 'black'
+                plot_kwargs_defaults['markerfacecolor'][key] = 'none'
+
+            elif key == 'Model':
+                plot_kwargs_defaults['linestyle'][key] = '-'
+                plot_kwargs_defaults['marker'][key] = None
+                plot_kwargs_defaults['color'][key] = 'red'
+                plot_kwargs_defaults['markerfacecolor'][key] = 'none'
+
+            else:
                 plot_kwargs_defaults['linestyle'][key] = '--'
                 plot_kwargs_defaults['marker'][key] = None
 
@@ -316,9 +326,79 @@ def plot_data_and_model(
         )
         for widget in fig.bottom_bar[0].controls.values():
             widget.slider_toggler.value = '-o-'
-
+        fig.autoscale()
         return fig
 
+    def data_and_model_to_datagroup(
+        self,
+        energy: sc.Variable | None = None,
+        add_background: bool = True,
+        include_components: bool = True,
+    ) -> sc.DataGroup:
+        """
+        Create a scipp DataGroup containing the experimental data, model calculation and optionally
+        the individual components of the model.
+
+        Parameters
+        ----------
+        energy : sc.Variable | None, default=None
+            The energy values to use for calculating the model. If None, uses the energy from the
+            experiment.
+        add_background : bool, default=True
+            Whether to add background components to the sample model components when creating the
+            DataGroup.
+        include_components : bool, default=True
+            Whether to include the individual components of the model in the DataGroup. If False,
+            only the total model will be included.
+
+        Raises
+        ------
+        ValueError
+            If there is no data to include in the DataGroup, or if there are no Q values available
+            for creating the DataGroup.
+
+        TypeError
+            If add_background is not True or False. If include_components is not True or False.
+
+        Returns
+        -------
+        sc.DataGroup
+            A DataGroup containing the experimental data, model calculation, and optionally the
+            individual components of the model.
+        """
+        if self.experiment.binned_data is None:
+            raise ValueError('No data to include in DataGroup. Please load data first.')
+
+        if self.Q is None:
+            raise ValueError(
+                'No Q values available for creating DataGroup. Please check the experiment data.'
+            )
+
+        if not isinstance(add_background, bool):
+            raise TypeError('add_background must be True or False.')
+
+        if not isinstance(include_components, bool):
+            raise TypeError('include_components must be True or False.')
+
+        energy = self._verify_energy(energy)
+
+        if energy is None:
+            energy = self.energy
+
+        data_and_model = {
+            'Data': self.experiment.binned_data,
+            'Model': self._create_model_array(energy=energy),
+        }
+
+        if include_components:
+            components = self._create_components_dataset(
+                add_background=add_background, energy=energy
+            )
+            for key in components:
+                data_and_model[key] = components[key]
+
+        return sc.DataGroup(data_and_model)
+
     def parameters_to_dataset(self) -> sc.Dataset:
         """
         Creates a scipp dataset with copies of the Parameters in the model.

src/easydynamics/analysis/analysis1d.py

@@ -291,56 +291,128 @@ def plot_data_and_model(
         **kwargs : dict[str, Any]
             Keyword arguments to pass to the plotting function.
 
-        Raises
-        ------
-        ValueError
-            If no data is available to plot.
-
         Returns
         -------
         InteractiveFigure
             A plot of the data and model.
         """
         import plopp as pp
 
+        data_and_model = self.data_and_model_to_datagroup(
+            energy=energy,
+            add_background=add_background,
+            include_components=plot_components,
+        )
+
         plot_kwargs_defaults = {
             'title': self.display_name,
-            'linestyle': {'Data': 'none', 'Model': '-'},
-            'marker': {'Data': 'o', 'Model': 'none'},
-            'color': {'Data': 'black', 'Model': 'red'},
-            'markerfacecolor': {'Data': 'none', 'Model': 'none'},
+            'linestyle': {},
+            'marker': {},
+            'color': {},
+            'markerfacecolor': {},
         }
 
+        for key in data_and_model:
+            if key == 'Data':
+                plot_kwargs_defaults['linestyle'][key] = 'none'
+                plot_kwargs_defaults['marker'][key] = 'o'
+                plot_kwargs_defaults['color'][key] = 'black'
+                plot_kwargs_defaults['markerfacecolor'][key] = 'none'
+
+            elif key == 'Model':
+                plot_kwargs_defaults['linestyle'][key] = '-'
+                plot_kwargs_defaults['marker'][key] = None
+                plot_kwargs_defaults['color'][key] = 'red'
+                plot_kwargs_defaults['markerfacecolor'][key] = 'none'
+
+            else:
+                plot_kwargs_defaults['linestyle'][key] = '--'
+                plot_kwargs_defaults['marker'][key] = None
+
+        # Overwrite defaults with any user-provided kwargs
+        plot_kwargs_defaults.update(kwargs)
+
+        return pp.plot(
+            data_and_model,
+            **plot_kwargs_defaults,
+        )
+
+    def data_and_model_to_datagroup(
+        self,
+        energy: sc.Variable | None = None,
+        add_background: bool = True,
+        include_components: bool = True,
+    ) -> sc.DataGroup:
+        """
+        Create a scipp DataGroup containing the experimental data, model calculation, and
+        optionally the individual components.
+
+        Parameters
+        ----------
+        energy : sc.Variable | None, default=None
+            Optional energy grid to use for the model calculation. If None, the energy grid from
+            the experiment is used.
+        add_background : bool, default=True
+            Whether to add the background to the model prediction when plotting individual
+            components.
+        include_components : bool, default=True
+            Whether to include the individual components of the model in the DataGroup. If True,
+            the DataGroup will include a DataArray for each component with the component's display
+            name as the key
+
+        Raises
+        ------
+        ValueError
+            If no data is available in the experiment to include in the DataGroup. If no Q values
+            are available in the experiment to create the DataGroup. If Q_index is not set to
+            create the DataGroup.
+        TypeError
+            If add_background is not a boolean. If include_components is not a boolean.
+
+        Returns
+        -------
+        sc.DataGroup
+            A DataGroup containing the experimental data, model calculation, and optionally the
+            individual components.
+        """
+
         if self.experiment.binned_data is None:
-            raise ValueError('No data to plot. Please load data first.')
+            raise ValueError('No data to include in DataGroup. Please load data first.')
+
+        if self.Q is None:
+            raise ValueError(
+                'No Q values available for creating DataGroup. Please check the experiment data.'
+            )
+
+        if not isinstance(add_background, bool):
+            raise TypeError('add_background must be True or False.')
+
+        if not isinstance(include_components, bool):
+            raise TypeError('include_components must be True or False.')
+
+        if self.Q_index is None:
+            raise ValueError('Q_index must be set to create DataGroup.')
 
         energy = self._verify_energy(energy)
+
         if energy is None:
             energy = self._masked_energy
 
-        # Create a dataset containing the data, model, and individual
-        # components for plotting.
         data_and_model = {
             'Data': self.experiment.binned_data['Q', self.Q_index],
             'Model': self._create_model_array(energy=energy),
         }
 
-        if plot_components:
+        if include_components:
             components = self._create_components_dataset_single_Q(
-                add_background=add_background, energy=energy
+                add_background=add_background,
+                energy=energy,
             )
-            for comp_name in components:
-                data_and_model[comp_name] = components[comp_name]
-                plot_kwargs_defaults['linestyle'][comp_name] = '--'
-                plot_kwargs_defaults['marker'][comp_name] = None
 
-        # Overwrite defaults with any user-provided kwargs
-        plot_kwargs_defaults.update(kwargs)
+            for key in components:
+                data_and_model[key] = components[key]
 
-        return pp.plot(
-            data_and_model,
-            **plot_kwargs_defaults,
-        )
+        return sc.DataGroup(data_and_model)
 
     def fix_energy_offset(self) -> None:
         """Fix the energy offset parameter for the current Q index."""
@@ -385,30 +457,6 @@ def _on_Q_index_changed(self) -> None:
         self._masked_energy = masked_energy
         self._convolver = self._create_convolver()
 
-    def _verify_energy(self, energy: sc.Variable | None) -> sc.Variable | None:
-        """
-        Verify that the provided energy is the correct type.
-
-        Parameters
-        ----------
-        energy : sc.Variable | None
-            The energy to verify.
-
-        Raises
-        ------
-        TypeError
-            If energy is not a sc.Variable or None.
-
-        Returns
-        -------
-        sc.Variable | None
-            The verified energy, or None if no energy is provided.
-        """
-
-        if energy is not None and not isinstance(energy, sc.Variable):
-            raise TypeError(f'Energy must be a sc.Variable or None. Got {type(energy)}.')
-        return energy
-
     def _calculate_energy_with_offset(
         self,
         energy: sc.Variable,