Move fluence calcs to physics from landscape. Update LandScapeBuilder to accommodate config and segments

src/pg_rad/physics/fluence.py

@@ -1,7 +1,12 @@
+from typing import TYPE_CHECKING
+
 import numpy as np
 
+if TYPE_CHECKING:
+    from pg_rad.landscape.landscape import Landscape
 
-def phi_single_source(
+
+def phi(
         r: float,
         activity: float | int,
         branching_ratio: float,
@@ -27,11 +32,51 @@ def phi_single_source(
     mu_mass_air *= 0.1
     mu_air = mu_mass_air * air_density
 
-    phi = (
+    phi_r = (
         activity
         * branching_ratio
         * np.exp(-mu_air * r)
         / (4 * np.pi * r**2)
     )
 
-    return phi
+    return phi_r
+
+
+def calculate_fluence_at(landscape: "Landscape", pos: tuple):
+    total_phi = 0.
+    for source in landscape.point_sources:
+        r = source.distance_to(pos)
+        phi_source = phi(
+            r=r,
+            activity=source.activity,
+            branching_ratio=source.isotope.b,
+            mu_mass_air=source.isotope.mu_mass_air,
+            air_density=landscape.air_density
+        )
+        total_phi += phi_source
+    return total_phi
+
+
+def calculate_fluence_along_path(
+    landscape: "Landscape",
+    points_per_segment: int = 10
+):
+    
+    phi_result = []
+ 
+    path = landscape.path
+    waypoints = list(zip(path.x_list, path.y_list))
+
+    for w, wp1 in zip(waypoints, waypoints[1:]):
+        x_ref, y_ref = zip(w, wp1)
+ 
+        x = np.linspace(x_ref[0], x_ref[1], points_per_segment)
+        y = np.interp(x, x_ref, y_ref)
+        z = np.full(x.shape, fill_value=path.z)
+        
+        for pos in zip(x, y, z):
+            phi_segment = calculate_fluence_at(landscape, pos)
+            phi_result.append(phi_segment)
+    
+    return phi_result
+