PhononWorkChain: add max concurrent running pw workchains

Fixes #52

Add the `settings.max_concurrent_base_workchains` input to the `PhononWorkChain`
to run only up to a maximum number of PwBaseWorkChain at the same time. This is
particularly useful for low symmetry materials where many displacements are generated.
This avoids to overload both the AiiDA daemon and especially the HPC. Moreover, this
even allows for running on the local machine (where AiiDA is installed) this workflow.

src/aiida_vibroscopy/workflows/phonons/base.py

@@ -14,7 +14,7 @@
 from aiida import orm
 from aiida.common.extendeddicts import AttributeDict
 from aiida.common.lang import type_check
-from aiida.engine import WorkChain, calcfunction, if_
+from aiida.engine import WorkChain, calcfunction, if_, while_
 from aiida.plugins import CalculationFactory, DataFactory, WorkflowFactory
 from aiida_quantumespresso.calculations.functions.create_kpoints_from_distance import create_kpoints_from_distance
 from aiida_quantumespresso.workflows.protocols.utils import ProtocolMixin
@@ -133,6 +133,10 @@ def define(cls, spec):
             'settings.sleep_submission_time', valid_type=(int, float), non_db=True, default=3.0,
             help='Time in seconds to wait before submitting subsequent displaced structure scf calculations.',
         )
+        spec.input(
+            'settings.max_concurrent_base_workchains', valid_type=int, non_db=True,  default=20,
+            help='Maximum number of concurrent running `PwBaseWorkChain`.'
+        )
         spec.input(
             'clean_workdir', valid_type=orm.Bool, default=lambda: orm.Bool(False),
             help='If `True`, work directories of all called calculation will be cleaned at the end of execution.'
@@ -143,7 +147,10 @@ def define(cls, spec):
             cls.set_reference_kpoints,
             cls.run_base_supercell,
             cls.inspect_base_supercell,
-            cls.run_forces,
+            cls.run_supercells,
+            while_(cls.should_run_forces)(
+                cls.run_forces,
+            ),
             cls.inspect_all_runs,
             cls.set_phonopy_data,
             if_(cls.should_run_phonopy)(
@@ -379,8 +386,8 @@ def inspect_base_supercell(self):
             fermi_energy = parameters.fermi_energy
             self.ctx.is_insulator, _ = orm.find_bandgap(bands, fermi_energy=fermi_energy)
 
-    def run_forces(self):
-        """Run an scf for each supercell with displacements."""
+    def run_supercells(self):
+        """Run supercell with displacements."""
         if self.ctx.plus_hubbard or self.ctx.old_plus_hubbard:
             supercells = get_supercells_for_hubbard(
                 preprocess_data=self.ctx.preprocess_data,
@@ -389,12 +396,27 @@ def run_forces(self):
         else:
             supercells = self.ctx.preprocess_data.calcfunctions.get_supercells_with_displacements()
 
+        self.ctx.supercells = []
+        for key, value in supercells.items():
+            self.ctx.supercells.append((key, value))
+
         self.out('supercells', supercells)
 
+    def should_run_forces(self):
+        """Whether to run or not forces."""
+        return len(self.ctx.supercells) > 0
+
+    def run_forces(self):
+        """Run an scf for each supercell with displacements."""
         base_key = f'{self._RUN_PREFIX}_0'
         base_out = self.ctx[base_key].outputs
 
-        for key, supercell in supercells.items():
+        n_base_parallel = self.inputs.settings.max_concurrent_base_workchains
+        if self.inputs.settings.max_concurrent_base_workchains < 0:
+            n_base_parallel = len(self.ctx.supercells)
+
+        for _ in self.ctx.supercells[:n_base_parallel]:
+            key, supercell = self.ctx.supercells.pop(0)
             num = key.split('_')[-1]
             label = f'{self._RUN_PREFIX}_{num}'
 

tests/workflows/phonons/test_phonon.py

@@ -8,6 +8,7 @@
 #################################################################################
 """Tests for the :mod:`workflows.phonons.phonon` module."""
 from aiida import orm
+from aiida.common import AttributeDict
 from aiida_quantumespresso.data.hubbard_structure import HubbardStructureData
 import pytest
 
@@ -29,13 +30,13 @@ def _generate_workchain_phonon(structure=None, append_inputs=None, return_inputs
         inputs = {
             'scf': scf_inputs,
             'settings': {
-                'sleep_submission_time': 0.
+                'sleep_submission_time': 0.,
             },
             'symmetry': {},
         }
 
         if return_inputs:
-            return inputs
+            return AttributeDict(inputs)
 
         if append_inputs is not None:
             inputs.update(append_inputs)
@@ -223,23 +224,53 @@ def test_inspect_base_supercell(
     assert process.ctx.is_insulator
 
 
+@pytest.mark.usefixtures('aiida_profile')
+def test_run_supercells(generate_workchain_phonon):
+    """Test `PhononWorkChain.run_supercells` method."""
+    process = generate_workchain_phonon()
+    process.setup()
+    process.run_supercells()
+
+    assert 'supercells' in process.outputs
+    assert 'supercells' in process.ctx
+    assert 'supercell_1' in process.outputs['supercells']
+
+
+@pytest.mark.usefixtures('aiida_profile')
+def test_should_run_forces(generate_workchain_phonon):
+    """Test `PhononWorkChain.should_run_forces` method."""
+    process = generate_workchain_phonon()
+    process.setup()
+    process.run_supercells()
+    assert process.should_run_forces()
+
+
 @pytest.mark.usefixtures('aiida_profile')
 def test_run_forces(generate_workchain_phonon, generate_base_scf_workchain_node):
     """Test `PhononWorkChain.run_forces` method."""
-    process = generate_workchain_phonon()
+    append_inputs = {
+        'settings': {
+            'sleep_submission_time': 0.,
+            'max_concurrent_base_workchains': 1,
+        }
+    }
+    process = generate_workchain_phonon(append_inputs=append_inputs)
 
     process.setup()
     process.set_reference_kpoints()
     process.run_base_supercell()
+    process.run_supercells()
 
     assert 'scf_supercell_0'
 
+    num_supercells = len(process.ctx.supercells)
     process.ctx.scf_supercell_0 = generate_base_scf_workchain_node()
     process.run_forces()
 
     assert 'supercells' in process.outputs
     assert 'supercell_1' in process.outputs['supercells']
     assert 'scf_supercell_1' in process.ctx
+    assert num_supercells == len(process.ctx.supercells) + 1
 
 
 @pytest.mark.usefixtures('aiida_profile')
@@ -251,6 +282,7 @@ def test_run_forces_with_hubbard(generate_workchain_phonon, generate_base_scf_wo
     process.setup()
     process.set_reference_kpoints()
     process.run_base_supercell()
+    process.run_supercells()
 
     assert 'scf_supercell_0'
 
@@ -261,6 +293,7 @@ def test_run_forces_with_hubbard(generate_workchain_phonon, generate_base_scf_wo
     assert 'supercell_1' in process.outputs['supercells']
     assert isinstance(process.outputs['supercells']['supercell_1'], HubbardStructureData)
     assert 'scf_supercell_1' in process.ctx
+    assert len(process.ctx.supercells) == 0
 
 
 @pytest.mark.parametrize(('expected_result', 'exit_status'),

tests/workflows/protocols/test_phonon.py

@@ -82,11 +82,15 @@ def test_overrides(fixture_code, generate_structure):
         'displacement_generator': {
             'distance': 0.005
         },
+        'settings': {
+            'max_concurrent_base_workchains': 1,
+        }
     }
     builder = PhononWorkChain.get_builder_from_protocol(code, structure, overrides=overrides)
 
     assert builder.primitive_matrix.get_list() == [[1, 0, 0], [0, 1, 0], [0, 0, 1]]
     assert builder.displacement_generator.get_dict() == {'distance': 0.005}
+    assert builder.settings.max_concurrent_base_workchains == 1
 
 
 def test_phonon_properties(fixture_code, generate_structure):