From 7fd4a22060c97ec4d1df80bc5d50a1fbc3024f53 Mon Sep 17 00:00:00 2001
From: rlar <rlar>
Date: Mon, 29 Jan 2018 17:53:07 +0100
Subject: [PATCH] ni/niiter.c, bug fix, CKTrhsOld is meant to return the
 solution

when solving
  circuitmatrix . x = rhs
in function NIiter()

The result es expected to be delivered in CKTrhsOld.
CKTrhs is meant to store leftover garbage when returning from NIiter()

this can be seen most notably in CKTdump(), and in other iters,
  for example NIacIter()

as a consequence the solution of the second to last iteration
  was used, instead of the very last iteration.
This can be quite inaccurate if the second to last iteration
  was marked CKTnoncon by somebody.
In my case this was the caused by the convlimit option in xpsice
  which intentionally uses incorrect values and correctly markes
  the results unusable with CKTnoncon.
---
 src/maths/ni/niiter.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/maths/ni/niiter.c b/src/maths/ni/niiter.c
index 7611bb4a3..a2bec8b07 100644
--- a/src/maths/ni/niiter.c
+++ b/src/maths/ni/niiter.c
@@ -237,6 +237,7 @@ NIiter(CKTcircuit *ckt, int maxIter)
             if (ckt->CKTnoncon == 0) {
                 ckt->CKTstat->STATnumIter += iterno;
                 FREE(OldCKTstate0);
+                SWAP(double *, ckt->CKTrhs, ckt->CKTrhsOld);
                 return(OK);
             }
         } else if (ckt->CKTmode & MODEINITJCT) {