Handle non-diagonal noise in out of place SRA

Fixes #578. All of the other convergence tests were in place but the non-diagonal case was just missing a few little bits.

Supersedes #587

Author: ChrisRackauckas

src/perform_step/sra.jl

@@ -178,20 +178,34 @@ end
   g1 = integrator.g(uprev,p,t+c11*dt)
   k1 = integrator.f(uprev,p,t)
 
-  H01 = uprev + dt*a21*k1 + b21*chi2.*g1
+  if is_diagonal_noise(integrator.sol.prob)
+    H01 = uprev + dt*a21*k1 + b21*chi2.*g1
+  else
+    H01 = uprev + dt*a21*k1 + b21*g1*chi2
+  end
 
   g2 = integrator.g(H01,p,t+c12*dt)
   k2 = integrator.f(H01,p,t+c02*dt)
 
-  H02 = uprev + dt*(a31*k1 + a32*k2) + chi2.*(b31*g1 + b32*g2)
+  if is_diagonal_noise(integrator.sol.prob)
+    H02 = uprev + dt*(a31*k1 + a32*k2) + chi2.*(b31*g1 + b32*g2)
+  else
+    H02 = uprev + dt*(a31*k1 + a32*k2) + (b31*g1 + b32*g2)*chi2
+  end
+
 
   g3 = integrator.g(H02,p,t+c13*dt)
   k3 = integrator.f(H02,p,t+c03*dt)
 
   E₁ = dt*(α1*k1 + α2*k2 + α3*k3)
-  E₂ = chi2.*(beta21*g1 + beta22*g2 + beta23*g3)
 
-  u = uprev + E₁ + E₂ + W.dW.*(beta11*g1 + beta12*g2 + beta13*g3)
+  if is_diagonal_noise(integrator.sol.prob)
+    E₂ = chi2.*(beta21*g1 + beta22*g2 + beta23*g3)
+    u = uprev + E₁ + E₂ + W.dW.*(beta11*g1 + beta12*g2 + beta13*g3)
+  else
+    E₂ = (beta21*g1 + beta22*g2 + beta23*g3)*chi2
+    u = uprev + E₁ + E₂ + (beta11*g1 + beta12*g2 + beta13*g3)*W.dW
+  end
 
   if integrator.alg isa StochasticCompositeAlgorithm && integrator.alg.algs[1] isa SOSRA2
     ϱu = integrator.opts.internalnorm(k3 - k2, t)
@@ -255,7 +269,7 @@ end
     mul!(E₂,gtmp,chi2)
     @.. gtmp = beta11*g1 + beta12*g2 + beta13*g3
     mul!(E₁,gtmp,W.dW)
-    u = uprev + dt*(α1*k1 + α2*k2 + α3*k3) + E₂ + E₁
+    @.. u = uprev + dt*(α1*k1 + α2*k2 + α3*k3) + E₂ + E₁
   end
 
   if integrator.alg isa StochasticCompositeAlgorithm && integrator.alg.algs[1] isa SOSRA2

test/nondiagonal_tests.jl

@@ -108,8 +108,48 @@ prob = SDEProblem(f_morenoise,g_morenoise,ones(2),(0.0,1.0),
                   noise_rate_prototype=zeros(2,4))
 
 sol =solve(prob,dt=1/2^(3),EM())
+sol =solve(prob,dt=1/2^(3),SRA())
 sol =solve(prob,dt=1/2^(3),ISSEM())
 sol =solve(prob,dt=1/2^(3),ImplicitEM())
 sol =solve(prob,dt=1/2^(3),EulerHeun())
 sol =solve(prob,dt=1/2^(3),ImplicitEulerHeun())
 sol =solve(prob,dt=1/2^(3),ISSEulerHeun())
+
+
+f(du, u, p, t) = du .= u
+function g(du, u, p, t)
+    du .= [-0.80 -0.3; -0.8 0.3]
+end
+
+u0 = ones(2)
+dt = 1//2^(4)
+tspan = (0., 1.)
+
+prototype = zeros(2,2)
+
+iip_prob = SDEProblem{true}(f, g, u0, tspan, noise_rate_prototype = prototype)
+@test !(solve(iip_prob, EM(), dt = 0.1)[end] ≈ ones(2))
+@test !(solve(iip_prob, SOSRA())[end] ≈ ones(2))
+
+# Out of place regression tests
+
+f(u, p, t) = u
+function g(u, p, t)
+    return [-0.80 -0.3; -0.8 0.3]
+end
+
+u0 = ones(2)
+dt = 1//2^(4)
+tspan = (0., 1.)
+
+prototype = zeros(2,2)
+
+oop_prob = SDEProblem{false}(f, g, u0, tspan, noise_rate_prototype = prototype)
+oop_sol = solve(oop_prob, EM(), dt = dt)
+oop_sol = solve(oop_prob, SOSRA())
+sol =solve(oop_prob,dt=1/2^(3),EM())
+sol =solve(oop_prob,dt=1/2^(3),ISSEM())
+@test_broken sol =solve(oop_prob,dt=1/2^(3),ImplicitEM())
+sol =solve(oop_prob,dt=1/2^(3),EulerHeun())
+@test_broken sol =solve(oop_prob,dt=1/2^(3),ImplicitEulerHeun())
+sol =solve(oop_prob,dt=1/2^(3),ISSEulerHeun())