add function without ode and give GSParams into function

src/solver.jl

@@ -92,9 +92,9 @@ function grayscott!(du, u, p::GSParams, t=0)
 end
 
 # Run simulation
-function run_simulationG(tspan::Tuple{Float64,Float64}, N::Int)
+function run_simulationG(tspan::Tuple{Float64,Float64}, N::Int, GSP::GSParams)
     # Replace this in run_simulation
-    p = GSParams(N, 1.0, 0.16, 0.08, 0.060, 0.062)
+    p = GSP
 
     # Initial conditions: U = 1, V = 0 everywhere
     U = ones(N, N)
@@ -109,7 +109,45 @@ function run_simulationG(tspan::Tuple{Float64,Float64}, N::Int)
     y0 = vcat(vec(U), vec(V))
 
     prob = ODEProblem(grayscott!, y0, tspan, p)
-    sol = solve(prob, BS3(), saveat=100.0)  # or Rosenbrock23()
+    sol = solve(prob, BS3(), saveat=10.0)  # or Rosenbrock23()
 
     return sol
 end
+
+function run_simulationG_no_ode(tspan::Tuple{Float64,Float64}, N::Int, GSP::GSParams)
+    p = GSP
+    dx2 = p.dx^2
+    dt = 1.0  # fixed timestep
+
+    # Initialize U and V
+    U = ones(N, N)
+    V = zeros(N, N)
+
+    # Seed pattern in the center
+    center = N ÷ 2
+    radius = 10
+    U[center-radius:center+radius, center-radius:center+radius] .= 0.50
+    V[center-radius:center+radius, center-radius:center+radius] .= 0.25
+
+    # Store history for visualization (optional)
+    snapshots = []
+
+    for i in 1:tspan[2]
+        print("Running $i/$(tspan[2])\r")
+
+        lap_U = laplacianA(U, N, p.dx)
+        lap_V = laplacianA(V, N, p.dx)
+
+        UVV = U .* V .* V
+        dU = p.Du * lap_U .- UVV .+ p.F * (1 .- U)
+        dV = p.Dv * lap_V .+ UVV .- (p.F + p.k) .* V
+
+        U .+= dU * dt
+        V .+= dV * dt
+
+        if i % 100 == 0  # save every 100 steps
+            push!(snapshots, (copy(U), copy(V)))
+        end
+    end
+    return snapshots
+end