Activate Job Scheduler in launch_fluent

src/ansys/fluent/core/launcher/fluent_launcher_options.json

@@ -23,10 +23,6 @@
         },
         "fluent_format": "{}"
     },
-    "processor_count": {
-        "type": "int",
-        "fluent_format": " -t{}"
-    },
     "journal_filename": {
         "type": "str",
         "fluent_format": " -i {}"

src/ansys/fluent/core/launcher/launcher.py

@@ -16,6 +16,7 @@
 
 from ansys.fluent.core.fluent_connection import _FluentConnection
 from ansys.fluent.core.launcher.fluent_container import start_fluent_container
+from ansys.fluent.core.scheduler import build_parallel_options, load_machines
 from ansys.fluent.core.session import Session, _BaseSession, parse_server_info_file
 from ansys.fluent.core.session_meshing import Meshing
 from ansys.fluent.core.session_pure_meshing import PureMeshing
@@ -194,6 +195,10 @@ def _build_fluent_launch_args_string(**kwargs) -> str:
                     json_key = json.dumps(argval)
                 argval = fluent_map[json_key]
             launch_args_string += v["fluent_format"].replace("{}", str(argval))
+    addArgs = kwargs["additional_arguments"]
+    if "-t" not in addArgs and "-cnf=" not in addArgs:
+        mlist = load_machines(ncores=kwargs["processor_count"])
+        launch_args_string += " " + build_parallel_options(mlist)
     return launch_args_string
 
 
@@ -301,7 +306,8 @@ def launch_fluent(
         is used. Options are ``"double"`` and ``"single"``.
     processor_count : int, optional
         Number of processors. The default is ``None``, in which case ``1``
-        is used.
+        processor is used.  In job scheduler environments the total number of
+        allocated cores is clamped to this value.
     journal_filename : str, optional
         Name of the journal file to read. The default is ``None``.
     start_timeout : int, optional
@@ -365,6 +371,12 @@ def launch_fluent(
     -------
     ansys.fluent.session.Session
         Fluent session.
+
+    Notes
+    -----
+    In job scheduler environments such as SLURM, LSF, PBS, etc... the allocated
+    machines and core counts are queried from the scheduler environment and
+    passed to Fluent.
     """
     argvals = locals()
 

src/ansys/fluent/core/scheduler/__init__.py

@@ -1,9 +1,12 @@
 """A package providing job scheduler support."""
 
+import socket
+
 from ansys.fluent.core.scheduler.load_machines import load_machines  # noqa: F401
 from ansys.fluent.core.scheduler.machine_list import MachineList
 
-_fluentOpt = "-t%n% -cnf=%machineList%"
+_ncoresOpt = "-t%n%"
+_machinesOpt = " -cnf=%machineList%"
 _procSep = ":"
 _machineSep = ","
 
@@ -15,17 +18,33 @@ def build_parallel_options(machine_list: MachineList) -> str:
     ----------
     machine_list : MachineList
         List of machines obtained by calling `load_machines`.
+
+    Notes
+    -----
+    When running serial no options are passed back to the caller as Fluent can
+    be started without additional arguments in that case.
+
+    If the parallel options are being built on the same machine as Fluent is run
+    on, and it's local parallel, then the -cnf argument is not constructed.
     """
-    parOpt = _fluentOpt.replace("%n%", str(machine_list.number_of_cores))
-    cnfList = (
-        machine_list[0].host_name + _procSep + str(machine_list[0].number_of_cores)
-    )
-    for m in range(1, len(machine_list)):
-        cnfList += (
-            _machineSep
-            + machine_list[m].host_name
-            + _procSep
-            + str(machine_list[m].number_of_cores)
+    parOpt = ""
+    if (
+        machine_list.num_machines == 1
+        and socket.gethostname() == machine_list[0].host_name
+    ):
+        if machine_list.number_of_cores > 1:
+            parOpt = _ncoresOpt.replace("%n%", str(machine_list.number_of_cores))
+    else:
+        parOpt = _ncoresOpt.replace("%n%", str(machine_list.number_of_cores))
+        cnfList = (
+            machine_list[0].host_name + _procSep + str(machine_list[0].number_of_cores)
         )
-    parOpt = parOpt.replace("%machineList%", cnfList)
+        for m in range(1, len(machine_list)):
+            cnfList += (
+                _machineSep
+                + machine_list[m].host_name
+                + _procSep
+                + str(machine_list[m].number_of_cores)
+            )
+        parOpt += _machinesOpt.replace("%machineList%", cnfList)
     return parOpt

src/ansys/fluent/core/scheduler/load_machines.py

@@ -48,12 +48,12 @@ def load_machines(
     list for LSF, PBS_NODEFILE for PBS and SLURM_JOB_NODELIST on SLURM.
     Unsupported job schedulers may provide alternative ways of providing a list
     of machines, in that case the list must be pre-parsed and provided via the
-    machineDict parameter.
+    `machine_info` or `host_info` parameters.
 
-    Depending on the SLURM environment, the hostnames contained within the
-    SLURM_JOB_NODELIST variable may not be valid to ssh to. In that case we
-    cannot pass these names to the solver. So, in the SLURM branch there is a
-    test to check if we can ssh to the first host, if not, get 'actual' machine
+    In some SLURM environments, the hostnames contained within the variable
+    SLURM_JOB_NODELIST may not be valid to ssh to. In that case those names
+    cannot be passed to the solver. So, in the SLURM branch there is a test to
+    check if ssh to the first host is working, and if not, get 'actual' machine
     names using scontrol.
     """
 
@@ -101,7 +101,7 @@ def load_machines(
     elif ncores is None:
         machine_list = _get_local_machine(1)
 
-    if ncores is not None and machine_list.number_of_cores != ncores:
+    if ncores is not None and ncores < machine_list.number_of_cores:
         # If both machine list and number of cores are provided, edit the
         # machine list to use exactly the number of cores indicated.
         machine_list = _restrict_machines_to_core_count(machine_list, ncores)