fix bug where output concatenation in batch_apply fails with states w…

…ith different numbers of atoms

psiflow/data/dataset.py

@@ -415,14 +415,33 @@ def _concatenate_multiple(*args: list[np.ndarray]) -> list[np.ndarray]:
     Note:
         This function is wrapped as a Parsl app and executed using the default_threads executor.
     """
+    def pad_arrays(
+        arrays: list[np.ndarray],
+        pad_dimension: int = 1,
+    ) -> list[np.ndarray]:
+        ndims = np.array([len(a.shape) for a in arrays])
+        assert np.all(ndims == ndims[0])
+        assert np.all(pad_dimension < ndims)
+
+        pad_size = max([a.shape[pad_dimension] for a in arrays])
+        for i in range(len(arrays)):
+            shape = list(arrays[i].shape)
+            shape[pad_dimension] = pad_size - shape[pad_dimension]
+            padding = np.zeros(tuple(shape)) + np.nan
+            arrays[i] = np.concatenate((arrays[i], padding), axis=pad_dimension)
+        return arrays
+
     narrays = len(args[0])
     for arg in args:
         assert isinstance(arg, list)
     assert all([len(a) == narrays for a in args])
 
     concatenated = []
     for i in range(narrays):
-        concatenated.append(np.concatenate([arg[i] for arg in args]))
+        arrays = [arg[i] for arg in args]
+        if len(arrays[0].shape) > 1:
+            pad_arrays(arrays)
+        concatenated.append(np.concatenate(tuple(arrays)))
     return concatenated
 
 

tests/test_function.py

@@ -5,6 +5,7 @@
 from parsl.data_provider.files import File # type: ignore
 
 import psiflow
+from psiflow.data import Dataset
 from psiflow.functions import (
     EinsteinCrystalFunction,
     HarmonicFunction,
@@ -254,6 +255,12 @@ def test_hamiltonian_arithmetic(dataset):
     assert hamiltonian == hamiltonian + zero
     assert 2 * hamiltonian + zero == 2 * hamiltonian
 
+    geometries = [dataset[i].result() for i in [0, -1]]
+    natoms = [len(geometry) for geometry in geometries]
+    forces = zero.compute(geometries, 'forces', batch_size=1).result()
+    assert np.all(forces[0, :natoms[0]] == 0.0)
+    assert np.all(forces[-1, :natoms[1]] == 0.0)
+
 
 def test_subtract(dataset):
     einstein = EinsteinCrystal(dataset[0], force_constant=1.0)