Revert "fix scalar flux time derviatve scaling"

yardasol · yardasol · commit 85e3d3a8bc37 · 2026-04-09T11:34:14.000-05:00
This reverts commit 774fb9b.
diff --git a/src/random_ray/flat_source_domain.cpp b/src/random_ray/flat_source_domain.cpp
@@ -2022,8 +2022,7 @@ void FlatSourceDomain::compute_single_phi_prime(SourceRegionHandle& srh)
 
     double scalar_flux_time_derivative =
       A0 * srh.scalar_flux_old(g) + srh.scalar_flux_rhs_bd(g);
-    srh.phi_prime(g) =
-      scalar_flux_time_derivative * inverse_vbar / (4 * PI * sigma_t);
+    srh.phi_prime(g) = scalar_flux_time_derivative * inverse_vbar / sigma_t;
   }
 }
 
@@ -2050,7 +2049,7 @@ void FlatSourceDomain::compute_single_T1(SourceRegionHandle& srh)
 
     double scalar_flux_time_derivative_2 =
       B0 * srh.scalar_flux_old(g) + srh.scalar_flux_rhs_bd_2(g);
-    scalar_flux_time_derivative_2 *= inverse_vbar / (4 * PI);
+    scalar_flux_time_derivative_2 *= inverse_vbar;
 
     // Divide by sigma_t to save time during transport
     srh.T1(g) =

Original file line number	Diff line number	Diff line change
`@@ -2022,8 +2022,7 @@ void FlatSourceDomain::compute_single_phi_prime(SourceRegionHandle& srh)`
`2022`	`2022`
`2023`	`2023`	`double scalar_flux_time_derivative =`
`2024`	`2024`	`A0 * srh.scalar_flux_old(g) + srh.scalar_flux_rhs_bd(g);`
`2025`		`- srh.phi_prime(g) =`
`2026`		`- scalar_flux_time_derivative * inverse_vbar / (4 * PI * sigma_t);`
	`2025`	`+ srh.phi_prime(g) = scalar_flux_time_derivative * inverse_vbar / sigma_t;`
`2027`	`2026`	`}`
`2028`	`2027`	`}`
`2029`	`2028`
`@@ -2050,7 +2049,7 @@ void FlatSourceDomain::compute_single_T1(SourceRegionHandle& srh)`
`2050`	`2049`
`2051`	`2050`	`double scalar_flux_time_derivative_2 =`
`2052`	`2051`	`B0 * srh.scalar_flux_old(g) + srh.scalar_flux_rhs_bd_2(g);`
`2053`		`- scalar_flux_time_derivative_2 = inverse_vbar / (4 PI);`
	`2052`	`+ scalar_flux_time_derivative_2 *= inverse_vbar;`
`2054`	`2053`
`2055`	`2054`	`// Divide by sigma_t to save time during transport`
`2056`	`2055`	`srh.T1(g) =`