Update reconstruction tutorial with simpler API (#330)

Author: eigenvivek

diffdrr/drr.py

@@ -160,10 +160,10 @@ def forward(
 @patch
 def render(
     self: DRR,
-    density: torch.tensor,
-    source: torch.tensor,
-    target: torch.tensor,
-    mask_to_channels: bool,
+    density: torch.tensor,  # Volume from which to render DRRs
+    source: torch.tensor,  # World coordinates of X-ray source
+    target: torch.tensor,  # World coordinates of X-ray target
+    mask_to_channels: bool = False,  # If True, structures from the CT mask are rendered in separate channels
     **kwargs,
 ):
     # Initialize the image with the length of each cast ray

notebooks/api/00_drr.ipynb

@@ -279,10 +279,10 @@
     "@patch\n",
     "def render(\n",
     "    self: DRR,\n",
-    "    density: torch.tensor,\n",
-    "    source: torch.tensor,\n",
-    "    target: torch.tensor,\n",
-    "    mask_to_channels: bool,\n",
+    "    density: torch.tensor,  # Volume from which to render DRRs\n",
+    "    source: torch.tensor,  # World coordinates of X-ray source\n",
+    "    target: torch.tensor,  # World coordinates of X-ray target\n",
+    "    mask_to_channels: bool = False,  # If True, structures from the CT mask are rendered in separate channels\n",
     "    **kwargs,\n",
     "):\n",
     "    # Initialize the image with the length of each cast ray\n",