Use namedtuple to improve API while still maintaining backward compat…

…ibility (#380)

* Use namedtuple to improve API

* improve

examples/ase_interface.py

@@ -16,7 +16,6 @@
 
 ###############################################################################
 # To begin with, let's first import the modules we will use:
-from __future__ import print_function
 from ase.lattice.cubic import Diamond
 from ase.md.langevin import Langevin
 from ase.optimize import BFGS

examples/energy_force.py

@@ -9,7 +9,6 @@
 
 ###############################################################################
 # To begin with, let's first import the modules we will use:
-from __future__ import print_function
 import torch
 import torchani
 
@@ -43,7 +42,7 @@
 
 ###############################################################################
 # Now let's compute energy and force:
-_, energy = model((species, coordinates))
+energy = model((species, coordinates)).energies
 derivative = torch.autograd.grad(energy.sum(), coordinates)[0]
 force = -derivative
 

examples/jit.py

@@ -46,9 +46,9 @@
 
 ###############################################################################
 # And here is the result:
-_, energies_ensemble = model((species, coordinates))
-_, energies_single = model[0]((species, coordinates))
-_, energies_ensemble_jit = loaded_compiled_model((species, coordinates))
-_, energies_single_jit = loaded_compiled_model0((species, coordinates))
+energies_ensemble = model((species, coordinates)).energies
+energies_single = model[0]((species, coordinates)).energies
+energies_ensemble_jit = loaded_compiled_model((species, coordinates)).energies
+energies_single_jit = loaded_compiled_model0((species, coordinates)).energies
 print('Ensemble energy, eager mode vs loaded jit:', energies_ensemble.item(), energies_ensemble_jit.item())
 print('Single network energy, eager mode vs loaded jit:', energies_single.item(), energies_single_jit.item())

examples/load_from_neurochem.py

@@ -75,7 +75,7 @@
 
 ###############################################################################
 # Now let's compute energies using the ensemble directly:
-_, energy = nnp1((species, coordinates))
+energy = nnp1((species, coordinates)).energies
 derivative = torch.autograd.grad(energy.sum(), coordinates)[0]
 force = -derivative
 print('Energy:', energy.item())
@@ -89,7 +89,7 @@
 
 ###############################################################################
 # We can do the same thing with the single model:
-_, energy = nnp2((species, coordinates))
+energy = nnp2((species, coordinates)).energies
 derivative = torch.autograd.grad(energy.sum(), coordinates)[0]
 force = -derivative
 print('Energy:', energy.item())

examples/nnp_training.py

@@ -286,7 +286,7 @@ def validate():
         true_energies = batch_y['energies']
         predicted_energies = []
         for chunk_species, chunk_coordinates in batch_x:
-            _, chunk_energies = model((chunk_species, chunk_coordinates))
+            chunk_energies = model((chunk_species, chunk_coordinates)).energies
             predicted_energies.append(chunk_energies)
         predicted_energies = torch.cat(predicted_energies)
         total_mse += mse_sum(predicted_energies, true_energies).item()
@@ -343,7 +343,7 @@ def validate():
 
         for chunk_species, chunk_coordinates in batch_x:
             num_atoms.append((chunk_species >= 0).to(true_energies.dtype).sum(dim=1))
-            _, chunk_energies = model((chunk_species, chunk_coordinates))
+            chunk_energies = model((chunk_species, chunk_coordinates)).energies
             predicted_energies.append(chunk_energies)
 
         num_atoms = torch.cat(num_atoms)

examples/nnp_training_force.py

@@ -231,7 +231,7 @@ def validate():
         true_energies = batch_y['energies']
         predicted_energies = []
         for chunk_species, chunk_coordinates in batch_x:
-            _, chunk_energies = model((chunk_species, chunk_coordinates))
+            chunk_energies = model((chunk_species, chunk_coordinates)).energies
             predicted_energies.append(chunk_energies)
         predicted_energies = torch.cat(predicted_energies)
         total_mse += mse_sum(predicted_energies, true_energies).item()
@@ -299,7 +299,7 @@ def validate():
             # that we could compute force from it
             chunk_coordinates.requires_grad_(True)
 
-            _, chunk_energies = model((chunk_species, chunk_coordinates))
+            chunk_energies = model((chunk_species, chunk_coordinates)).energies
 
             # We can use torch.autograd.grad to compute force. Remember to
             # create graph so that the loss of the force can contribute to

examples/vibration_analysis.py

@@ -54,7 +54,7 @@
 # To do vibration analysis, we first need to generate a graph that computes
 # energies from species and coordinates. The code to generate a graph of energy
 # is the same as the code to compute energy:
-_, energies = model((species, coordinates))
+energies = model((species, coordinates)).energies
 
 ###############################################################################
 # We can now use the energy graph to compute analytical Hessian matrix:

torchani/aev.py

@@ -1,10 +1,15 @@
 import torch
 from torch import Tensor
 import math
-from typing import Tuple, Optional
+from typing import Tuple, Optional, NamedTuple
 from torch.jit import Final
 
 
+class SpeciesAEV(NamedTuple):
+    species: Tensor
+    aevs: Tensor
+
+
 def cutoff_cosine(distances: Tensor, cutoff: float) -> Tensor:
     # assuming all elements in distances are smaller than cutoff
     return 0.5 * torch.cos(distances * (math.pi / cutoff)) + 0.5
@@ -356,7 +361,7 @@ def constants(self):
         return self.Rcr, self.EtaR, self.ShfR, self.Rca, self.ShfZ, self.EtaA, self.Zeta, self.ShfA
 
     def forward(self, input_: Tuple[Tensor, Tensor], cell: Optional[Tensor] = None,
-                pbc: Optional[Tensor] = None) -> Tuple[Tensor, Tensor]:
+                pbc: Optional[Tensor] = None) -> SpeciesAEV:
         """Compute AEVs
 
         Arguments:
@@ -384,7 +389,7 @@ def forward(self, input_: Tuple[Tensor, Tensor], cell: Optional[Tensor] = None,
                 for that direction.
 
         Returns:
-            tuple: Species and AEVs. species are the species from the input
+            NamedTuple: Species and AEVs. species are the species from the input
             unchanged, and AEVs is a tensor of shape
             ``(C, A, self.aev_length())``
         """
@@ -398,4 +403,5 @@ def forward(self, input_: Tuple[Tensor, Tensor], cell: Optional[Tensor] = None,
             cutoff = max(self.Rcr, self.Rca)
             shifts = compute_shifts(cell, pbc, cutoff)
 
-        return species, compute_aev(species, coordinates, cell, shifts, self.triu_index, self.constants(), self.sizes)
+        aev = compute_aev(species, coordinates, cell, shifts, self.triu_index, self.constants(), self.sizes)
+        return SpeciesAEV(species, aev)

torchani/ase.py

@@ -93,11 +93,11 @@ def calculate(self, atoms=None, properties=['energy'],
                 strain_y = self.strain(cell, displacement_y, 1)
                 strain_z = self.strain(cell, displacement_z, 2)
                 cell = cell + strain_x + strain_y + strain_z
-            _, aev = self.aev_computer((species, coordinates), cell=cell, pbc=pbc)
+            aev = self.aev_computer((species, coordinates), cell=cell, pbc=pbc).aevs
         else:
-            _, aev = self.aev_computer((species, coordinates))
+            aev = self.aev_computer((species, coordinates)).aevs
 
-        _, energy = self.nn((species, aev))
+        energy = self.nn((species, aev)).energies
         energy *= ase.units.Hartree
         self.results['energy'] = energy.item()
         self.results['free_energy'] = energy.item()

torchani/nn.py

@@ -1,6 +1,11 @@
 import torch
 from torch import Tensor
-from typing import Tuple
+from typing import Tuple, NamedTuple
+
+
+class SpeciesEnergies(NamedTuple):
+    species: Tensor
+    energies: Tensor
 
 
 class ANIModel(torch.nn.Module):
@@ -26,7 +31,7 @@ def __init__(self, modules):
     def __getitem__(self, i):
         return self.module_list[i]
 
-    def forward(self, species_aev: Tuple[Tensor, Tensor]) -> Tuple[Tensor, Tensor]:
+    def forward(self, species_aev: Tuple[Tensor, Tensor]) -> SpeciesEnergies:
         species, aev = species_aev
         species_ = species.flatten()
         aev = aev.flatten(0, 1)
@@ -40,7 +45,7 @@ def forward(self, species_aev: Tuple[Tensor, Tensor]) -> Tuple[Tensor, Tensor]:
                 input_ = aev.index_select(0, midx)
                 output.masked_scatter_(mask, m(input_).flatten())
         output = output.view_as(species)
-        return species, torch.sum(output, dim=1)
+        return SpeciesEnergies(species, torch.sum(output, dim=1))
 
 
 class Ensemble(torch.nn.Module):
@@ -51,12 +56,12 @@ def __init__(self, modules):
         self.modules_list = torch.nn.ModuleList(modules)
         self.size = len(self.modules_list)
 
-    def forward(self, species_input: Tuple[Tensor, Tensor]) -> Tuple[Tensor, Tensor]:
+    def forward(self, species_input: Tuple[Tensor, Tensor]) -> SpeciesEnergies:
         sum_ = 0
         for x in self.modules_list:
             sum_ += x(species_input)[1]
         species, _ = species_input
-        return species, sum_ / self.size
+        return SpeciesEnergies(species, sum_ / self.size)
 
     def __getitem__(self, i):
         return self.modules_list[i]
@@ -69,7 +74,7 @@ def __init__(self, *modules):
         super(Sequential, self).__init__()
         self.modules_list = torch.nn.ModuleList(modules)
 
-    def forward(self, input_: Tuple[Tensor, Tensor]) -> Tuple[Tensor, Tensor]:
+    def forward(self, input_: Tuple[Tensor, Tensor]):
         for module in self.modules_list:
             input_ = module(input_)
         return input_

torchani/utils.py

@@ -4,7 +4,8 @@
 import math
 import numpy as np
 from collections import defaultdict
-from typing import Tuple
+from typing import Tuple, NamedTuple
+from .nn import SpeciesEnergies
 
 
 def pad(species):
@@ -211,12 +212,12 @@ def subtract_from_dataset(self, atomic_properties, properties):
         properties['energies'] = energies
         return atomic_properties, properties
 
-    def forward(self, species_energies: Tuple[Tensor, Tensor]) -> Tuple[Tensor, Tensor]:
+    def forward(self, species_energies: Tuple[Tensor, Tensor]) -> SpeciesEnergies:
         """(species, molecular energies)->(species, molecular energies + sae)
         """
         species, energies = species_energies
         sae = self.sae(species).to(energies.device)
-        return species, energies.to(sae.dtype) + sae
+        return SpeciesEnergies(species, energies.to(sae.dtype) + sae)
 
 
 class ChemicalSymbolsToInts:
@@ -269,6 +270,11 @@ def hessian(coordinates, energies=None, forces=None):
     ], dim=1)
 
 
+class FreqsModes(NamedTuple):
+    freqs: Tensor
+    modes: Tensor
+
+
 def vibrational_analysis(masses, hessian, unit='cm^-1'):
     """Computing the vibrational wavenumbers from hessian."""
     if unit != 'cm^-1':
@@ -292,7 +298,7 @@ def vibrational_analysis(masses, hessian, unit='cm^-1'):
     # converting from sqrt(hartree / (amu * angstrom^2)) to cm^-1
     wavenumbers = frequencies * 17092
     modes = (eigenvectors.t() * inv_sqrt_mass).reshape(frequencies.numel(), -1, 3)
-    return wavenumbers, modes
+    return FreqsModes(wavenumbers, modes)
 
 
 __all__ = ['pad', 'pad_atomic_properties', 'present_species', 'hessian',