Fixup some branch checks

usadelndsoc/solver.py

@@ -322,19 +322,26 @@ class Solver:
 
             do_restart = False
 
+            if not check_step(Phi, dx):
+                if frozen_M and not update_skipped:
+                    _log_solve.info("Bad step: force Jacobian update")
+                    update_skipped = True
+                    continue
+                elif restart == 0:
+                    do_restart = True
+                else:
+                    for k in range(1, 5):
+                        if check_step(Phi, dx / 5**k):
+                            dx /= 5**k
+                            s /= 5**k
+                            _log_solve.debug(f"    bad step, reduced by {5**k}")
+                            break
+                    else:
+                        _log_solve.debug(f"    bad step, nothing helped")
+
             if s >= 0.75:
                 M = None
                 dx *= 0.75 / s
-
-                if not check_step(Phi, dx):
-                    _log_solve.debug("    bad step")
-                    if frozen_M and not update_skipped:
-                        _log_solve.info("Bad step: force Jacobian update")
-                        update_skipped = True
-                        continue
-                    elif restart == 0:
-                        do_restart = True
-
                 tiny_count = 0
             elif s == 0:
                 if restart == 0:
@@ -375,6 +382,9 @@ class Solver:
             _log_solve.error("Failed to solve (maxiter)")
             Phi[...] = np.nan
             M = None
+            import pdb
+
+            pdb.set_trace()
 
         self._M = M