.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "galley_examples/MAF/plot_2D_0_Rb2O2p25SiO2.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_galley_examples_MAF_plot_2D_0_Rb2O2p25SiO2.py: 2D MAF data of Rb2O.2.25SiO2 glass ================================== .. GENERATED FROM PYTHON SOURCE LINES 7-16 The following example is an application of the statistical learning method in determining the distribution of the nuclear shielding tensor parameters from a 2D magic-angle flipping (MAF) spectrum. In this example, we use the 2D MAF spectrum [#f1]_ of :math:`\text{Rb}_2\text{O}\cdot2.25\text{SiO}_2` glass. Before getting started ---------------------- Import all relevant packages. .. GENERATED FROM PYTHON SOURCE LINES 16-28 .. code-block:: Python import csdmpy as cp import matplotlib.pyplot as plt import numpy as np from matplotlib import cm from csdmpy import statistics as stats from mrinversion.kernel.nmr import ShieldingPALineshape from mrinversion.kernel.utils import x_y_to_zeta_eta from mrinversion.linear_model import SmoothLassoCV, TSVDCompression from mrinversion.utils import plot_3d, to_Haeberlen_grid .. GENERATED FROM PYTHON SOURCE LINES 30-31 Setup for the matplotlib figures. .. GENERATED FROM PYTHON SOURCE LINES 31-44 .. code-block:: Python # function for plotting 2D dataset def plot2D(csdm_object, **kwargs): plt.figure(figsize=(4.5, 3.5)) ax = plt.subplot(projection="csdm") ax.imshow(csdm_object, cmap="gist_ncar_r", aspect="auto", **kwargs) ax.invert_xaxis() ax.invert_yaxis() plt.tight_layout() plt.show() .. GENERATED FROM PYTHON SOURCE LINES 45-53 Dataset setup ------------- Import the dataset '''''''''''''''''' Load the dataset. In this example, we import the dataset as the CSDM data-object. .. GENERATED FROM PYTHON SOURCE LINES 53-64 .. code-block:: Python # The 2D MAF dataset in csdm format filename = "https://zenodo.org/record/3964531/files/Rb2O-2_25SiO2-MAF.csdf" data_object = cp.load(filename) # For inversion, we only interest ourselves with the real part of the complex dataset. data_object = data_object.real # We will also convert the coordinates of both dimensions from Hz to ppm. _ = [item.to("ppm", "nmr_frequency_ratio") for item in data_object.dimensions] .. GENERATED FROM PYTHON SOURCE LINES 65-69 Here, the variable ``data_object`` is a `CSDM `_ object that holds the real part of the 2D MAF dataset. The plot of the 2D MAF dataset is .. GENERATED FROM PYTHON SOURCE LINES 69-71 .. code-block:: Python plot2D(data_object) .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_001.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_001.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 72-76 There are two dimensions in this dataset. The dimension at index 0, the horizontal dimension in the figure, is the pure anisotropic dimension, while the dimension at index 1, the vertical dimension, is the isotropic chemical shift dimension. The number of coordinates along the respective dimensions is .. GENERATED FROM PYTHON SOURCE LINES 76-78 .. code-block:: Python print(data_object.shape) .. rst-class:: sphx-glr-script-out .. code-block:: none (128, 512) .. GENERATED FROM PYTHON SOURCE LINES 79-81 with 128 points along the anisotropic dimension (index 0) and 512 points along the isotropic chemical shift dimension (index 1). .. GENERATED FROM PYTHON SOURCE LINES 83-99 Prepping the data for inversion ''''''''''''''''''''''''''''''' **Step-1: Data Alignment** When using the csdm objects with the ``mrinversion`` package, the dimension at index 0 must be the dimension undergoing the linear inversion. In this example, we plan to invert the pure anisotropic shielding line-shape. Since the anisotropic dimension in ``data_object`` is already at index 0, no further action is required. **Step-2: Optimization** Notice, the signal from the 2D MAF dataset occupies a small fraction of the two-dimensional frequency grid. Though you may choose to proceed with the inversion directly onto this dataset, it is not computationally optimum. For optimum performance, trim the dataset to the region of relevant signals. Use the appropriate array indexing/slicing to select the signal region. .. GENERATED FROM PYTHON SOURCE LINES 99-102 .. code-block:: Python data_object_truncated = data_object[:, 250:285] plot2D(data_object_truncated) .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_002.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_002.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 103-106 In the above code, we truncate the isotropic chemical shifts, dimension at index 1, to coordinate between indexes 250 and 285. The isotropic shift coordinates from the truncated dataset are .. GENERATED FROM PYTHON SOURCE LINES 106-108 .. code-block:: Python print(data_object_truncated.dimensions[1].coordinates) .. rst-class:: sphx-glr-script-out .. code-block:: none [-127.28980343 -125.33932238 -123.38884134 -121.4383603 -119.48787926 -117.53739821 -115.58691717 -113.63643613 -111.68595509 -109.73547404 -107.784993 -105.83451196 -103.88403092 -101.93354987 -99.98306883 -98.03258779 -96.08210675 -94.1316257 -92.18114466 -90.23066362 -88.28018258 -86.32970153 -84.37922049 -82.42873945 -80.47825841 -78.52777736 -76.57729632 -74.62681528 -72.67633423 -70.72585319 -68.77537215 -66.82489111 -64.87441006 -62.92392902 -60.97344798] ppm .. GENERATED FROM PYTHON SOURCE LINES 109-125 Linear Inversion setup ---------------------- Dimension setup ''''''''''''''' In a generic linear-inverse problem, one needs to define two sets of dimensions---the dimensions undergoing a linear transformation, and the dimensions onto which the inversion method transforms the data. In the line-shape inversion, the two sets of dimensions are the anisotropic dimension and the `x`-`y` dimensions. **Anisotropic-dimension:** The dimension of the dataset that holds the pure anisotropic frequency contributions. In ``mrinversion``, this must always be the dimension at index 0 of the data object. .. GENERATED FROM PYTHON SOURCE LINES 125-127 .. code-block:: Python anisotropic_dimension = data_object_truncated.dimensions[0] .. GENERATED FROM PYTHON SOURCE LINES 128-130 **x-y dimensions:** The two inverse dimensions corresponding to the `x` and `y`-axis of the `x`-`y` grid. .. GENERATED FROM PYTHON SOURCE LINES 130-135 .. code-block:: Python inverse_dimensions = [ cp.LinearDimension(count=25, increment="400 Hz", label="x"), # the `x`-dimension. cp.LinearDimension(count=25, increment="400 Hz", label="y"), # the `y`-dimension. ] .. GENERATED FROM PYTHON SOURCE LINES 136-143 Generating the kernel ''''''''''''''''''''' For MAF datasets, the line-shape kernel corresponds to the pure nuclear shielding anisotropy line-shapes. Use the :class:`~mrinversion.kernel.nmr.ShieldingPALineshape` class to generate a shielding line-shape kernel. .. GENERATED FROM PYTHON SOURCE LINES 143-153 .. code-block:: Python lineshape = ShieldingPALineshape( anisotropic_dimension=anisotropic_dimension, inverse_dimension=inverse_dimensions, channel="29Si", magnetic_flux_density="9.4 T", rotor_angle="90°", rotor_frequency="13 kHz", number_of_sidebands=4, ) .. GENERATED FROM PYTHON SOURCE LINES 154-172 Here, ``lineshape`` is an instance of the :class:`~mrinversion.kernel.nmr.ShieldingPALineshape` class. The required arguments of this class are the `anisotropic_dimension`, `inverse_dimension`, and `channel`. We have already defined the first two arguments in the previous sub-section. The value of the `channel` argument is the nucleus observed in the MAF experiment. In this example, this value is '29Si'. The remaining arguments, such as the `magnetic_flux_density`, `rotor_angle`, and `rotor_frequency`, are set to match the conditions under which the 2D MAF spectrum was acquired. Note for the MAF measurements the rotor angle is usually :math:`90^\circ` for the anisotropic dimension. The value of the `number_of_sidebands` argument is the number of sidebands calculated for each line-shape within the kernel. Unless, you have a lot of spinning sidebands in your MAF dataset, the value of this argument is generally low. Here, we calculate four spinning sidebands per line-shape within in the kernel. Once the ShieldingPALineshape instance is created, use the :meth:`~mrinversion.kernel.nmr.ShieldingPALineshape.kernel` method of the instance to generate the MAF line-shape kernel. .. GENERATED FROM PYTHON SOURCE LINES 172-175 .. code-block:: Python K = lineshape.kernel(supersampling=1) print(K.shape) .. rst-class:: sphx-glr-script-out .. code-block:: none (128, 625) .. GENERATED FROM PYTHON SOURCE LINES 176-179 The kernel ``K`` is a NumPy array of shape (128, 625), where the axes with 128 and 625 points are the anisotropic dimension and the features (x-y coordinates) corresponding to the :math:`25\times 25` `x`-`y` grid, respectively. .. GENERATED FROM PYTHON SOURCE LINES 181-186 Data Compression '''''''''''''''' Data compression is optional but recommended. It may reduce the size of the inverse problem and, thus, further computation time. .. GENERATED FROM PYTHON SOURCE LINES 186-192 .. code-block:: Python new_system = TSVDCompression(K, data_object_truncated) compressed_K = new_system.compressed_K compressed_s = new_system.compressed_s print(f"truncation_index = {new_system.truncation_index}") .. rst-class:: sphx-glr-script-out .. code-block:: none compression factor = 1.471264367816092 truncation_index = 87 .. GENERATED FROM PYTHON SOURCE LINES 193-205 Solving the inverse problem --------------------------- Smooth LASSO cross-validation ''''''''''''''''''''''''''''' Solve the smooth-lasso problem. Use the statistical learning ``SmoothLassoCV`` method to solve the inverse problem over a range of α and λ values and determine the best nuclear shielding tensor parameter distribution for the given 2D MAF dataset. Considering the limited build time for the documentation, we'll perform the cross-validation over a smaller :math:`5 \times 5` `x`-`y` grid. You may increase the grid resolution for your problem if desired. .. GENERATED FROM PYTHON SOURCE LINES 205-222 .. code-block:: Python # setup the pre-defined range of alpha and lambda values lambdas = 10 ** (-4.1 - 1.25 * (np.arange(5) / 4)) alphas = 10 ** (-5.5 - 1.25 * (np.arange(5) / 4)) # setup the smooth lasso cross-validation class s_lasso = SmoothLassoCV( alphas=alphas, # A numpy array of alpha values. lambdas=lambdas, # A numpy array of lambda values. sigma=0.0045, # The standard deviation of noise from the 2D MAF data. folds=10, # The number of folds in n-folds cross-validation. inverse_dimension=inverse_dimensions, # previously defined inverse dimensions. ) # run the fit method on the compressed kernel and compressed data. s_lasso.fit(K=compressed_K, s=compressed_s) .. GENERATED FROM PYTHON SOURCE LINES 223-229 The optimum hyper-parameters '''''''''''''''''''''''''''' Use the :attr:`~mrinversion.linear_model.SmoothLassoCV.hyperparameters` attribute of the instance for the optimum hyper-parameters, :math:`\alpha` and :math:`\lambda`, determined from the cross-validation. .. GENERATED FROM PYTHON SOURCE LINES 229-231 .. code-block:: Python print(s_lasso.hyperparameters) .. rst-class:: sphx-glr-script-out .. code-block:: none {'alpha': np.float64(7.498942093324558e-07), 'lambda': np.float64(3.868120546330525e-05)} .. GENERATED FROM PYTHON SOURCE LINES 232-239 The cross-validation surface '''''''''''''''''''''''''''' Optionally, you may want to visualize the cross-validation error curve/surface. The :attr:`~mrinversion.linear_model.SmoothLassoCV.cross_validation_curve` attribute of the instance holds a CSDM object of the CV surface. For convenience, we provide a ``cv_plot`` function. .. GENERATED FROM PYTHON SOURCE LINES 239-241 .. code-block:: Python s_lasso.cv_plot() .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_003.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_003.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 242-247 The optimum solution '''''''''''''''''''' The :attr:`~mrinversion.linear_model.SmoothLassoCV.f` attribute of the instance holds the solution corresponding to the optimum hyper-parameters, .. GENERATED FROM PYTHON SOURCE LINES 247-249 .. code-block:: Python f_sol = s_lasso.f # f_sol is a CSDM object. .. GENERATED FROM PYTHON SOURCE LINES 250-257 where ``f_sol`` is the optimum solution. The fit residuals ''''''''''''''''' To calculate the residuals between the data and predicted data(fit), use the :meth:`~mrinversion.linear_model.SmoothLassoCV.residuals` method, as follows, .. GENERATED FROM PYTHON SOURCE LINES 257-263 .. code-block:: Python residuals = s_lasso.residuals(K=K, s=data_object_truncated) # residuals is a CSDM object. # The plot of the residuals. plot2D(residuals, vmax=data_object_truncated.max(), vmin=data_object_truncated.min()) .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_004.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_004.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 264-266 The standard deviation of the residuals is close to the standard deviation of the noise, :math:`\sigma = 0.0043`. .. GENERATED FROM PYTHON SOURCE LINES 266-268 .. code-block:: Python residuals.std() .. rst-class:: sphx-glr-script-out .. code-block:: none .. GENERATED FROM PYTHON SOURCE LINES 269-274 Saving the solution ''''''''''''''''''' To serialize the solution (nuclear shielding tensor parameter distribution) to a file, use the `save()` method of the CSDM object, for example, .. GENERATED FROM PYTHON SOURCE LINES 274-277 .. code-block:: Python f_sol.save("Rb2O.2.25SiO2_inverse.csdf") # save the solution residuals.save("Rb2O.2.25SiO2_residue.csdf") # save the residuals .. GENERATED FROM PYTHON SOURCE LINES 278-289 Data Visualization ------------------ At this point, we have solved the inverse problem and obtained an optimum distribution of the nuclear shielding tensor parameters from the 2D MAF dataset. You may use any data visualization and interpretation tool of choice for further analysis. In the following sections, we provide minimal visualization and analysis to complete the case study. Visualizing the 3D solution ''''''''''''''''''''''''''' .. GENERATED FROM PYTHON SOURCE LINES 289-303 .. code-block:: Python # Normalize the solution f_sol /= f_sol.max() # Convert the coordinates of the solution, `f_sol`, from Hz to ppm. [item.to("ppm", "nmr_frequency_ratio") for item in f_sol.dimensions] # The 3D plot of the solution plt.figure(figsize=(5, 4.4)) ax = plt.subplot(projection="3d") plot_3d(ax, f_sol, x_lim=[0, 150], y_lim=[0, 150], z_lim=[-50, -150]) plt.tight_layout() plt.show() .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_005.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_005.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 304-307 From the 3D plot, we observe two distinct regions: one for the :math:`\text{Q}^4` sites and another for the :math:`\text{Q}^3` sites. Select the respective regions by using the appropriate array indexing, .. GENERATED FROM PYTHON SOURCE LINES 307-313 .. code-block:: Python Q4_region = f_sol[0:7, 0:7, 4:25] Q4_region.description = "Q4 region" Q3_region = f_sol[0:8, 10:24, 11:30] Q3_region.description = "Q3 region" .. GENERATED FROM PYTHON SOURCE LINES 314-315 The plot of the respective regions is shown below. .. GENERATED FROM PYTHON SOURCE LINES 315-331 .. code-block:: Python plt.figure(figsize=(5, 4.4)) ax = plt.subplot(projection="3d") plot_3d( ax, [Q4_region, Q3_region], x_lim=[0, 150], # the x-limit y_lim=[0, 150], # the y-limit z_lim=[-50, -150], # the z-limit cmap=[cm.Reds_r, cm.Blues_r], # colormaps for each volume box=True, # draw a box around the region ) ax.legend() plt.tight_layout() plt.show() .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_006.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_006.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-script-out .. code-block:: none /home/docs/checkouts/readthedocs.org/user_builds/mrinversion/checkouts/stable/examples/MAF/plot_2D_0_Rb2O2p25SiO2.py:327: UserWarning: No artists with labels found to put in legend. Note that artists whose label start with an underscore are ignored when legend() is called with no argument. ax.legend() .. GENERATED FROM PYTHON SOURCE LINES 332-338 Visualizing the isotropic projections. '''''''''''''''''''''''''''''''''''''' Because the :math:`\text{Q}^4` and :math:`\text{Q}^3` regions are fully resolved after the inversion, evaluating the contributions from these regions is trivial. For examples, the distribution of the isotropic chemical shifts for these regions are .. GENERATED FROM PYTHON SOURCE LINES 338-372 .. code-block:: Python # Isotropic chemical shift projection of the 2D MAF dataset. data_iso = data_object_truncated.sum(axis=0) data_iso /= data_iso.max() # normalize the projection # Isotropic chemical shift projection of the tensor distribution dataset. f_sol_iso = f_sol.sum(axis=(0, 1)) # Isotropic chemical shift projection of the tensor distribution for the Q4 region. Q4_region_iso = Q4_region.sum(axis=(0, 1)) # Isotropic chemical shift projection of the tensor distribution for the Q3 region. Q3_region_iso = Q3_region.sum(axis=(0, 1)) # Normalize the three projections. f_sol_iso_max = f_sol_iso.max() f_sol_iso /= f_sol_iso_max Q4_region_iso /= f_sol_iso_max Q3_region_iso /= f_sol_iso_max # The plot of the different projections. plt.figure(figsize=(5.5, 3.5)) ax = plt.subplot(projection="csdm") ax.plot(f_sol_iso, "--k", label="tensor") ax.plot(Q4_region_iso, "r", label="Q4") ax.plot(Q3_region_iso, "b", label="Q3") ax.plot(data_iso, "-k", label="MAF") ax.plot(data_iso - f_sol_iso - 0.1, "gray", label="residuals") ax.set_title("Isotropic projection") ax.invert_xaxis() plt.legend() plt.tight_layout() plt.show() .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_007.png :alt: Isotropic projection :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_007.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 373-380 Analysis -------- For the analysis, we use the `statistics `_ module of the csdmpy package. Following is the moment analysis of the 3D volumes for both the :math:`\text{Q}^4` and :math:`\text{Q}^3` regions up to the second moment. .. GENERATED FROM PYTHON SOURCE LINES 380-399 .. code-block:: Python int_Q4 = stats.integral(Q4_region) # volume of the Q4 distribution mean_Q4 = stats.mean(Q4_region) # mean of the Q4 distribution std_Q4 = stats.std(Q4_region) # standard deviation of the Q4 distribution int_Q3 = stats.integral(Q3_region) # volume of the Q3 distribution mean_Q3 = stats.mean(Q3_region) # mean of the Q3 distribution std_Q3 = stats.std(Q3_region) # standard deviation of the Q3 distribution print("Q4 statistics") print(f"\tpopulation = {100 * int_Q4 / (int_Q4 + int_Q3)}%") print("\tmean\n\t\tx:\t{}\n\t\ty:\t{}\n\t\tiso:\t{}".format(*mean_Q4)) print("\tstandard deviation\n\t\tx:\t{}\n\t\ty:\t{}\n\t\tiso:\t{}".format(*std_Q4)) print("Q3 statistics") print(f"\tpopulation = {100 * int_Q3 / (int_Q4 + int_Q3)}%") print("\tmean\n\t\tx:\t{}\n\t\ty:\t{}\n\t\tiso:\t{}".format(*mean_Q3)) print("\tstandard deviation\n\t\tx:\t{}\n\t\ty:\t{}\n\t\tiso:\t{}".format(*std_Q3)) .. rst-class:: sphx-glr-script-out .. code-block:: none Q4 statistics population = 11.860363291161903% mean x: 8.331081020291267 ppm y: 8.731483455379806 ppm iso: -98.03432766930999 ppm standard deviation x: 4.1774701204199784 ppm y: 4.517399560552298 ppm iso: 5.3562950171049835 ppm Q3 statistics population = 88.1396367088381% mean x: 10.340979298538242 ppm y: 79.85428069523789 ppm iso: -88.9229571919152 ppm standard deviation x: 6.370406645506944 ppm y: 8.003938353049707 ppm iso: 4.37385683706002 ppm .. GENERATED FROM PYTHON SOURCE LINES 400-404 The statistics shown above are according to the respective dimensions, that is, the `x`, `y`, and the isotropic chemical shifts. To convert the `x` and `y` statistics to commonly used :math:`\zeta_\sigma` and :math:`\eta_\sigma` statistics, use the :func:`~mrinversion.kernel.utils.x_y_to_zeta_eta` function. .. GENERATED FROM PYTHON SOURCE LINES 404-424 .. code-block:: Python mean_ζη_Q3 = x_y_to_zeta_eta(*mean_Q3[0:2]) # error propagation for calculating the standard deviation std_ζ = (std_Q3[0] * mean_Q3[0]) ** 2 + (std_Q3[1] * mean_Q3[1]) ** 2 std_ζ /= mean_Q3[0] ** 2 + mean_Q3[1] ** 2 std_ζ = np.sqrt(std_ζ) std_η = (std_Q3[1] * mean_Q3[0]) ** 2 + (std_Q3[0] * mean_Q3[1]) ** 2 std_η /= (mean_Q3[0] ** 2 + mean_Q3[1] ** 2) ** 2 std_η = (4 / np.pi) * np.sqrt(std_η) print("Q3 statistics") print(f"\tpopulation = {100 * int_Q3 / (int_Q4 + int_Q3)}%") print("\tmean\n\t\tζ:\t{}\n\t\tη:\t{}\n\t\tiso:\t{}".format(*mean_ζη_Q3, mean_Q3[2])) print( "\tstandard deviation\n\t\tζ:\t{}\n\t\tη:\t{}\n\t\tiso:\t{}".format( std_ζ, std_η, std_Q3[2] ) ) .. rst-class:: sphx-glr-script-out .. code-block:: none Q3 statistics population = 88.1396367088381% mean ζ: 80.52106555558389 ppm η: 0.16396961458895587 iso: -88.9229571919152 ppm standard deviation ζ: 7.979708875049911 ppm η: 0.10121157315944869 iso: 4.37385683706002 ppm .. GENERATED FROM PYTHON SOURCE LINES 425-453 Result cross-verification ------------------------- The reported value for the Qn-species distribution from Baltisberger `et. al.` [#f1]_ is listed below and is consistent with the above result. .. list-table:: :widths: 7 15 28 25 25 :header-rows: 1 * - Species - Yield - Isotropic chemical shift, :math:`\delta_\text{iso}` - Shielding anisotropy, :math:`\zeta_\sigma`: - Shielding asymmetry, :math:`\eta_\sigma`: * - Q4 - :math:`11.0 \pm 0.3` % - :math:`-98.0 \pm 5.64` ppm - 0 ppm (fixed) - 0 (fixed) * - Q3 - :math:`89 \pm 0.1` % - :math:`-89.5 \pm 4.65` ppm - 80.7 ppm with a 6.7 ppm Gaussian broadening - 0 (fixed) .. GENERATED FROM PYTHON SOURCE LINES 455-460 Convert the 3D tensor distribution in Haeberlen parameters ---------------------------------------------------------- You may re-bin the 3D tensor parameter distribution from a :math:`\rho(\delta_\text{iso}, x, y)` distribution to :math:`\rho(\delta_\text{iso}, \zeta_\sigma, \eta_\sigma)` distribution as follows. .. GENERATED FROM PYTHON SOURCE LINES 460-468 .. code-block:: Python # Create the zeta and eta dimensions,, as shown below. zeta = cp.as_dimension(np.arange(40) * 4 - 40, unit="ppm", label="zeta") eta = cp.as_dimension(np.arange(16) / 15, label="eta") # Use the `to_Haeberlen_grid` function to convert the tensor parameter distribution. fsol_Hae = to_Haeberlen_grid(f_sol, zeta, eta) .. GENERATED FROM PYTHON SOURCE LINES 469-471 The 3D plot ''''''''''' .. GENERATED FROM PYTHON SOURCE LINES 471-477 .. code-block:: Python plt.figure(figsize=(5, 4.4)) ax = plt.subplot(projection="3d") plot_3d(ax, fsol_Hae, x_lim=[0, 1], y_lim=[-40, 120], z_lim=[-50, -150], alpha=0.4) plt.tight_layout() plt.show() .. image-sg:: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_008.png :alt: plot 2D 0 Rb2O2p25SiO2 :srcset: /galley_examples/MAF/images/sphx_glr_plot_2D_0_Rb2O2p25SiO2_008.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 478-485 References ---------- .. [#f1] Baltisberger, J. H., Florian, P., Keeler, E. G., Phyo, P. A., Sanders, K. J., Grandinetti, P. J.. Modifier cation effects on 29Si nuclear shielding anisotropies in silicate glasses, J. Magn. Reson. 268 (2016) 95 – 106. `doi:10.1016/j.jmr.2016.05.003 `_. .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 17.542 seconds) .. _sphx_glr_download_galley_examples_MAF_plot_2D_0_Rb2O2p25SiO2.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: plot_2D_0_Rb2O2p25SiO2.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: plot_2D_0_Rb2O2p25SiO2.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: plot_2D_0_Rb2O2p25SiO2.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_