rtx-cfd legacy GPU tests: the Jacobi Poisson test stops at 1e-4 (the accuracy check is the pin); rustfmt

crates/specialized/rtx-cfd/src/solvers/lbm/d3q19_gpu.rs

@@ -671,7 +671,8 @@ __global__ void d3q19_bounce_back_boundaries(
     }
 
     /// Get macroscopic variables at a specific point (copy from GPU)
-    pub fn gpu_macroscopic_variables_at(&mut self,
+    pub fn gpu_macroscopic_variables_at(
+        &mut self,
         x: usize,
         y: usize,
         z: usize,

crates/specialized/rtx-cfd/tests/kernels_tests.rs

@@ -48,7 +48,13 @@ mod cuda_tests {
         // Run advection kernel
         // CFL = v dt / dx ≈ 0.1: march 50 steps so the pulse moves several cells.
         for _ in 0..50 {
-            advection_kernel.apply(&d_phi, &mut d_phi_new, velocity as f32, dt as f32, dx as f32)?;
+            advection_kernel.apply(
+                &d_phi,
+                &mut d_phi_new,
+                velocity as f32,
+                dt as f32,
+                dx as f32,
+            )?;
             std::mem::swap(&mut d_phi, &mut d_phi_new);
         }
 
@@ -204,8 +210,10 @@ mod cuda_tests {
         d_source = kernel_manager.copy_to_device(&source)?;
 
         // Solve Poisson equation
-        let max_iterations = 20_000; // Jacobi needs O(n²) sweeps on this grid
+        // Jacobi needs O(n²) sweeps on this grid and its residual floor in f32 sits
-        let tolerance = 1e-6;
+        // above 1e-6; the accuracy check below is the pin, the stop is loose.
+        let max_iterations = 20_000;
+        let tolerance = 1e-4;
         let iterations = poisson_kernel.solve_2d(
             &mut d_phi,
             &d_source,