fix merge

Author: oscarddssmith

lib/OrdinaryDiffEqRosenbrock/src/rosenbrock_perform_step.jl

@@ -52,7 +52,7 @@ end
     linres = dolinsolve(integrator, cache.linsolve; A = repeat_step ? nothing : W, b = _vec(linsolve_tmp))
     veck₁ = _vec(k₁)
 
-    @.. veck₁ = vecu * neginvdtγ
+    @.. veck₁ = linres.u * neginvdtγ
     integrator.stats.nsolve += 1
 
     @.. u=uprev + dto2 * k₁
@@ -69,10 +69,9 @@ end
     @.. linsolve_tmp = f₁ - tmp
 
     linres = dolinsolve(integrator, linres.cache; b = _vec(linsolve_tmp))
-    vecu = _vec(linres.u)
     veck₂ = _vec(k₂)
 
-    @.. veck₂ = vecu * neginvdtγ + veck₁
+    @.. veck₂ = linres.u * neginvdtγ + veck₁
     integrator.stats.nsolve += 1
 
     @.. u = uprev + dt * k₂
@@ -95,7 +94,7 @@ end
 
         linres = dolinsolve(integrator, linres.cache; b = _vec(linsolve_tmp))
         veck3 = _vec(k₃)
-        @.. veck3 = vecu * neginvdtγ
+        @.. veck3 = linres.u * neginvdtγ
 
         integrator.stats.nsolve += 1
 
@@ -150,9 +149,8 @@ end
         integrator.opts.internalnorm, t)
 
     linres = dolinsolve(integrator, cache.linsolve; A = repeat_step ? nothing : W, b = _vec(linsolve_tmp))
-
     veck₁ = _vec(k₁)
-    @.. veck₁ = vecu * neginvdtγ
+    @.. veck₁ = linres.u * neginvdtγ
     integrator.stats.nsolve += 1
 
     @.. broadcast=false u=uprev + dto2 * k₁
@@ -169,9 +167,8 @@ end
     @.. broadcast=false linsolve_tmp=f₁ - tmp
 
     linres = dolinsolve(integrator, linres.cache; b = _vec(linsolve_tmp))
-    vecu = _vec(linres.u)
     veck₂ = _vec(k₂)
-    @.. veck₂ = vecu * neginvdtγ + veck₁
+    @.. veck₂ = linres.u * neginvdtγ + veck₁
     integrator.stats.nsolve += 1
 
     @.. tmp = uprev + dt * k₂
@@ -191,7 +188,7 @@ end
     linres = dolinsolve(integrator, linres.cache; b = _vec(linsolve_tmp))
     veck3 = _vec(k₃)
 
-    @.. veck3 = vecu * neginvdtγ
+    @.. veck3 = linres.u * neginvdtγ
     integrator.stats.nsolve += 1
 
     @.. broadcast=false u=uprev + dto6 * (k₁ + 4k₂ + k₃)