Added descriptive text to start of API examples

examples/antenna_like_GSSI_1500_fs.py

@@ -1,3 +1,14 @@
+"""An antenna model similar to a GSSI 1.5GHz antenna in free space
+
+This example model demonstrates how to use one of the built-in antenna models. 
+
+The geometry is 3D and the domain filled with freespace (the default). The 
+antenna model method is imported from its toolbox and the objects that build the
+antenna are iteratively added to the scene. The antenna can be rotated if
+desired, by rotating the objects that it is built from before they are added to
+the scene.
+"""
+
 from pathlib import Path
 
 import gprMax

examples/antenna_like_MALA_1200_fs.py

@@ -1,3 +1,12 @@
+"""An antenna model similar to a MALA 1.2GHz antenna in free space
+
+This example model demonstrates how to use one of the built-in antenna models. 
+
+The geometry is 3D and the domain filled with freespace (the default). The 
+antenna model method is imported from its toolbox and the objects that build the
+antenna are iteratively added to the scene.
+"""
+
 from pathlib import Path
 
 import gprMax

examples/antenna_wire_dipole_fs.py

@@ -1,3 +1,13 @@
+"""An half-wavelength wire dipole antenna in freespace
+
+This example model demonstrates how to a the transmission line source, which
+allows s-parameters and input impedances to be calculated after the simulation
+has run. 
+
+Both API and hash commands are given next to each other as a comparison of the
+two different methods that can be used to build a model.
+"""
+
 from pathlib import Path
 
 import gprMax

examples/cylinder_Bscan_GSSI_1500.py

@@ -1,3 +1,19 @@
+"""B-scan using a antenna model. 
+
+This example model demonstrates how to create a B-scan using an antenna model.
+
+The key part of this example is the concept of moving the antenna model in steps
+within the model domain to create multiple A-scans that build up the B-scan. 
+Each A-scan requires its own scene and a list of scenes it built up using a for
+loop. A different scene is required for each A-scan because the model geometry is
+changing, as the antenna geometry must be moved to a new position. This is in 
+contrast to simpler models that may use a Hertzian dipole source which has no
+associated 'geometry' and can be moved within a model without having to change
+the scene. When the all the scenes are created, the list of scenes is then passed
+to gprMax to run, noting the number of times 'n' gprMax is run corresponds to the 
+number of scenes, i.e. A-scans.
+"""
+
 from pathlib import Path
 
 import gprMax
@@ -51,4 +67,4 @@ for i in range(1, 55):
     scenes.append(scene)
 
 # Run model
-gprMax.run(scenes=scenes, n=54, geometry_only=False, outputfile=fn, gpu=None)
+gprMax.run(scenes=scenes, n=len(scenes), geometry_only=False, outputfile=fn, gpu=None)

examples/subgrids/cylinder_fs.py

@@ -1,6 +1,6 @@
 """Cylinder in freespace
 
-This example model is a basic demonstration of how to use subgrids. 
+This example model demonstrates how to use subgrids at a basic level.
 
 The geometry is 3D (required for any use of subgrids) and is of a water-filled 
 cylindrical object in freespace. The subgrid encloses the cylinderical object