Fix getting into upper branch with negative a.

1 files changed, 1 insertions, 1 deletions

diff --git a/init.c b/init.c
index 6467988..c5c633c 100644
--- a/init.c
+++ b/init.c
@@ -332,7 +332,7 @@ int td_solve(TDContext *td, double *coeffs_init[3])
                 "second branch where mass increases with decreasing amplitude\n",
                 td->amplitude, ce->a_converge);
     }
-    a0 = ce->a_converge;
+    a0 = SGN(td->amplitude) * ce->a_converge;
     tdi_constraint_eval_free(&ce);
 
     if (coeffs_init) {