Added func to estimate fractal building memory

gprMax/grid.py

@@ -177,7 +177,7 @@ class FDTDGrid:
             pml.initialise_field_arrays()
 
     def mem_est_basic(self):
-        """Estimate the amount of memory (RAM) required for grid arrays.
+        """Estimates the amount of memory (RAM) required for grid arrays.
 
         Returns:
             mem_use: int of memory (bytes).
@@ -217,7 +217,7 @@ class FDTDGrid:
         return mem_use
 
     def mem_est_dispersive(self):
-        """Estimate the amount of memory (RAM) required for dispersive grid arrays.
+        """Estimates the amount of memory (RAM) required for dispersive grid arrays.
 
         Returns:
             mem_use: int of memory (bytes).
@@ -228,6 +228,26 @@ class FDTDGrid:
                        np.dtype(config.get_model_config().materials['dispersivedtype']).itemsize)
         return mem_use
 
+    def mem_est_fractals(self):
+        """Estimates the amount of memory (RAM) required to build any objects
+            which use the FractalVolume/FractalSurface classes.
+
+        Returns:
+            mem_use: int of memory (bytes).
+        """
+        
+        mem_use = 0
+
+        for vol in self.fractalvolumes:
+            mem_use += (vol.nx * vol.ny * vol.nz * vol.dtype.itemsize)
+            for surface in vol.fractalsurfaces:
+                surfacedims = surface.get_surface_dims()
+                mem_use += (surfacedims[0] * 
+                            surfacedims[1] * 
+                            surface.dtype.itemsize)
+
+        return mem_use
+
     def tmx(self):
         """Add PEC boundaries to invariant direction in 2D TMx mode.
             N.B. 2D modes are a single cell slice of 3D grid.