Option to terminate solve by tolerance

src/solve.jl

@@ -1,17 +1,18 @@
-function solve(shot::Shot, its::Integer;
+function solve(shot::Shot, its::Integer; tol::Real=0.0, debug::Bool=false,
                P=nothing, dP_dψ=nothing, F_dF_dψ=nothing, Jt_R=nothing, Jt=nothing,
-               Pbnd=shot.Pbnd, Fbnd=shot.Fbnd, debug=false)
+               Pbnd=shot.Pbnd, Fbnd=shot.Fbnd)
     refill = Shot(shot; P, dP_dψ, F_dF_dψ, Jt_R, Jt, Pbnd, Fbnd)
-    return solve!(refill, its; debug)
+    return solve!(refill, its; tol, debug)
 end
 
-function solve!(refill::Shot, its::Integer; debug=false)
+function solve!(refill::Shot, its::Integer; tol::Real=0.0, debug::Bool=false)
     Fis, dFis, Fos, Ps = fft_prealloc_threaded(refill.M)
     A = preallocate_Astar(refill)
     L = 2 * refill.N * (2 * refill.M + 1)
     B = zeros(L)
     C = zeros(L)
     Ψold = 0.0
+    warn_concentric = false
     if debug
         _, _, Ψold = find_axis(refill)
     end
@@ -35,18 +36,32 @@ function solve!(refill::Shot, its::Integer; debug=false)
             (debug && i == 1) && println("    Trying full refit for first iteration")
             try
                 refill = refit(refill, Ψaxis, Raxis, Zaxis)
+                warn_concentric = false
             catch err
                 isa(err, InterruptException) && rethrow(err)
-                println("    Warning: Fell back to concentric surfaces due to ", typeof(err))
+                warn_concentric = true
+                if debug
+                    println("    Warning: Fit for iteration $i fell back to concentric surfaces due to ", typeof(err))
+                end
                 refill = refit_concentric(refill, Raxis, Zaxis)
             end
         end
 
+        error = abs((Ψaxis-Ψold)/Ψaxis)
         if debug
-            println("    Status: Ψaxis = $Ψaxis, Error: ", abs((Ψaxis-Ψold)/Ψaxis))
+            println("    Status: Ψaxis = $Ψaxis, Error: $error")
             Ψold = Ψaxis
         end
+        if error <= tol && i > 1
+            debug && println("DONE: Successful convergence")
+            break
+        end
+
+        if i == its && debug
+            println("DONE: maximum iterations")
+        end
     end
+    warn_concentric && println("WARNING: Final iteration used concentric surfaces and is likely inaccurate")
     return refill
 end