🤔 A bunch of questionable changes

* Stick to 50 `electron_maxstep`
* Refuse to increase number of SCF step if slope good
* Switch to `local-TF` mixing if lowsym or lowdim
* Finally, reduce mixing beta and increase ndim

src/aiida_quantumespresso/workflows/protocols/pw/base.yaml

@@ -24,7 +24,7 @@ default_inputs:
                 nosym: False
                 occupations: smearing
                 smearing: cold
-                degauss: 0.01
+                degauss: 0.02
             ELECTRONS:
                 electron_maxstep: 50
                 mixing_beta: 0.4
@@ -43,6 +43,8 @@ protocols:
             parameters:
                 CONTROL:
                     forc_conv_thr: 0.5e-4
+                SYSTEM:
+                    degauss: 0.0125
     fast:
         description: 'Protocol to perform the computation at low precision at minimal computational cost for testing purposes.'
         kpoints_distance: 0.50
@@ -53,3 +55,5 @@ protocols:
             parameters:
                 CONTROL:
                     forc_conv_thr: 1.e-3
+                SYSTEM:
+                    degauss: 0.0275

src/aiida_quantumespresso/workflows/pw/base.py

@@ -30,10 +30,13 @@ class PwBaseWorkChain(ProtocolMixin, BaseRestartWorkChain):
         'delta_threshold_degauss': 30,
         'delta_factor_degauss': 0.1,
         'delta_factor_mixing_beta': 0.5,
+        'delta_addition_mixing_ndim': 4,
         'delta_factor_max_seconds': 0.95,
         'delta_factor_nbnd': 0.05,
         'delta_minimum_nbnd': 4,
         'conv_slope_threshold': -0.1,
+        'conv_slope_range': 30,
+        'low_symmetry_threshold': 6
     })
 
     @classmethod
@@ -571,31 +574,56 @@ def handle_electronic_convergence_not_reached(self, calculation):
         """
         import numpy
 
-        scf_accuracy = calculation.tools.get_scf_accuracy(0)
+        scf_accuracy = calculation.tools.get_scf_accuracy(-1)[-self.defaults.conv_slope_range:]
         scf_accuracy_slope = numpy.polyfit(numpy.arange(0, len(scf_accuracy)), numpy.log(scf_accuracy), 1)[0]
 
-        if scf_accuracy_slope < self.defaults.conv_slope_threshold:
+        mixing_beta = self.ctx.inputs.parameters['ELECTRONS'].get('mixing_beta', self.defaults.qe.mixing_beta)
+        mixing_ndim = self.ctx.inputs.parameters['ELECTRONS'].get('mixing_ndim', self.defaults.qe.mixing_ndim)
+        mixing_mode = self.ctx.inputs.parameters['ELECTRONS'].get('mixing_mode', self.defaults.qe.mixing_mode)
+        low_symmetry_structure = (
+            len(calculation.outputs.output_parameters.get_dict()['symmetries']) < self.defaults.low_symmetry_threshold
+        )
+        low_dim_structure = calculation.inputs.structure.pbc != (True, True, True)
+
+        self.report(f'scf accuracy slope: {scf_accuracy_slope:.2f}')
+        self.report(f'mixing beta: {mixing_beta:.2f}')
+        self.report(f'mixing ndim: {mixing_ndim}')
+        self.report(f'mixing mode: {mixing_mode}')
+        self.report(f"structure symmetries: {len(calculation.outputs.output_parameters.get_dict()['symmetries'])}")
+        self.report(f'low symmetry structure: {low_symmetry_structure}')
+        self.report(f'low dimension structure: {low_dim_structure}')
 
+        if scf_accuracy_slope < self.defaults.conv_slope_threshold:
             action = (
-                'electronic convergence not reached but the scf accuracy is decreasing: restart from the last '
-                'calculation.'
+                f'electronic convergence not reached but the scf accuracy slope ({scf_accuracy_slope:.2f}) is smaller '
+                f'than the threshold ({self.defaults.conv_slope_threshold:.2f}): restart from the last calculation.'
             )
             self.set_restart_type(RestartType.FULL, calculation.outputs.remote_folder)
             self.report_error_handled(calculation, action)
             return ProcessHandlerReport(True)
 
-        mixing_beta = self.ctx.inputs.parameters.get('ELECTRONS', {}).get('mixing_beta', self.defaults.qe.mixing_beta)
+        if mixing_mode == 'plain' and (low_symmetry_structure or low_dim_structure):
+
+            self.ctx.inputs.parameters['ELECTRONS'].setdefault('mixing_mode', 'local-TF')
+            action = (
+                'electronic convergence not reached and structure is inhomogeneous: switch to local-TF mixing and '
+                'restart from the last calculation.'
+            )
+            self.set_restart_type(RestartType.FULL, calculation.outputs.remote_folder)
+            self.report_error_handled(calculation, action)
+            return ProcessHandlerReport(True)
 
         if mixing_beta > 0.1:
 
             mixing_beta_new = mixing_beta * self.defaults.delta_factor_mixing_beta
+            mixing_ndim_new = mixing_ndim + self.defaults.delta_addition_mixing_ndim
 
             self.ctx.inputs.parameters['ELECTRONS']['mixing_beta'] = mixing_beta_new
+            self.ctx.inputs.parameters['ELECTRONS']['mixing_ndim'] = mixing_ndim_new
             action = (
-                f'reduced beta mixing from {mixing_beta} to {mixing_beta_new} and restarting from the last '
-                'calculation'
+                f'reduced beta mixing from {mixing_beta} to {mixing_beta_new}, increased `mixing_ndim` from '
+                f'{mixing_ndim} to {mixing_ndim_new} and restarting from the last calculation.'
             )
-
             self.set_restart_type(RestartType.FULL, calculation.outputs.remote_folder)
             self.report_error_handled(calculation, action)
             return ProcessHandlerReport(True)

tests/workflows/protocols/pw/test_bands/test_default.yml

@@ -25,7 +25,7 @@ bands:
         mixing_beta: 0.4
         startingpot: file
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false
@@ -65,7 +65,7 @@ relax:
           electron_maxstep: 50
           mixing_beta: 0.4
         SYSTEM:
-          degauss: 0.01
+          degauss: 0.02
           ecutrho: 240.0
           ecutwfc: 30.0
           nosym: false
@@ -101,7 +101,7 @@ scf:
         electron_maxstep: 50
         mixing_beta: 0.4
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false

tests/workflows/protocols/pw/test_base/test_default.yml

@@ -22,7 +22,7 @@ pw:
       electron_maxstep: 50
       mixing_beta: 0.4
     SYSTEM:
-      degauss: 0.01
+      degauss: 0.02
       ecutrho: 240.0
       ecutwfc: 30.0
       nosym: false

tests/workflows/protocols/pw/test_relax/test_default.yml

@@ -26,7 +26,7 @@ base:
         electron_maxstep: 50
         mixing_beta: 0.4
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false
@@ -59,7 +59,7 @@ base_final_scf:
         electron_maxstep: 50
         mixing_beta: 0.4
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false

tests/workflows/protocols/test_pdos/test_default.yml

@@ -79,7 +79,7 @@ scf:
         electron_maxstep: 50
         mixing_beta: 0.4
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false

tests/workflows/protocols/xspectra/test_core/test_default.yml

@@ -41,7 +41,7 @@ scf:
         electron_maxstep: 50
         mixing_beta: 0.4
       SYSTEM:
-        degauss: 0.01
+        degauss: 0.02
         ecutrho: 240.0
         ecutwfc: 30.0
         nosym: false

tests/workflows/protocols/xspectra/test_crystal/test_default.yml

@@ -29,7 +29,7 @@ core:
           electron_maxstep: 50
           mixing_beta: 0.4
         SYSTEM:
-          degauss: 0.01
+          degauss: 0.02
           ecutrho: 240.0
           ecutwfc: 30.0
           nosym: false
@@ -105,7 +105,7 @@ relax:
           electron_maxstep: 50
           mixing_beta: 0.4
         SYSTEM:
-          degauss: 0.01
+          degauss: 0.02
           ecutrho: 240.0
           ecutwfc: 30.0
           nosym: false