I added a new class for incremental problems to problems.py.

pterasoftware/problems.py

@@ -3,6 +3,7 @@
 This module contains the following classes:
     SteadyProblem: This is a class for steady aerodynamics problems.
     UnsteadyProblem: This is a class for unsteady aerodynamics problems.
+    IncrementalUnsteadyProblem: This is a class for unsteady aerodynamics problems where the geometry is not precomputed for each time step.
 
 This module contains the following exceptions:
     None
@@ -141,3 +142,52 @@ def __init__(self, movement, only_final_results=False):
 
             # Append this steady problem to the list of steady problems.
             self.steady_problems.append(this_steady_problem)
+
+
+class IncrementalUnsteadyProblem:
+    """This is a class for unsteady aerodynamics problems where the geometry is not precomputed for each time step.
+
+    This class contains the following public methods:
+        None
+
+    This class contains the following class attributes:
+        None
+
+    Subclassing:
+        This class is not meant to be subclassed.
+    """
+
+    def __init__(self, incremental_movement):
+        """This is the initialization method.
+
+        :param incremental_movement: IncrementalMovement
+            This is the movement object that contains this problem's airplane and
+            operating point objects.
+        """
+        # Initialize the class attributes.
+        self.incremental_movement = incremental_movement
+        self.num_steps = self.incremental_movement.num_steps
+        self.delta_time = self.incremental_movement.delta_time
+
+        # Initialize empty lists that will hold the loads and load coefficients each
+        # airplane object experiences.
+        self.near_field_forces_wind_axes = []
+        self.near_field_force_coefficients_wind_axes = []
+        self.near_field_moments_wind_axes = []
+        self.near_field_moment_coefficients_wind_axes = []
+
+        # Get the airplane objects and the operating point object associated with
+        # the initial time step. This will be a list of the airplane snapshots associated
+        # with each base airplane.
+        these_airplanes = []
+        for this_base_airplane in incremental_movement.airplanes:
+            these_airplanes.append(this_base_airplane[0])
+
+        this_operating_point = incremental_movement.operating_points[0]
+
+        # Create a list to hold the steady problem's at each time step and add the first steady problem.
+        self.steady_problems = [
+            SteadyProblem(
+                airplanes=these_airplanes, operating_point=this_operating_point
+            )
+        ]