From ffe920117cdbd70d78bb70d8227914a89135c3c3 Mon Sep 17 00:00:00 2001
From: Pascal Kuthe <pascal.kuthe@semimod.de>
Date: Sun, 13 Nov 2022 16:16:38 +0100
Subject: [PATCH] calculate log frequency sweep such that start frequency and
 stop frequency are always exactly included

---
 src/spicelib/analysis/acan.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/spicelib/analysis/acan.c b/src/spicelib/analysis/acan.c
index da8d5bd39..1c45856c9 100644
--- a/src/spicelib/analysis/acan.c
+++ b/src/spicelib/analysis/acan.c
@@ -86,8 +86,9 @@ ACan(CKTcircuit *ckt, int restart)
                 fprintf(stderr, "ERROR: AC startfreq <= 0\n");
                 return E_PARMVAL;
             }
-            job->ACfreqDelta =
-                exp(log(10.0)/job->ACnumberSteps);
+            double num_steps = floor(fabs(log10(job->ACstopFreq/job->ACstartFreq))*job->ACnumberSteps);
+            job->ACfreqDelta = exp((log(job->ACstopFreq/job->ACstartFreq))/ num_steps);
+
             break;
         case OCTAVE:
             if (job->ACstartFreq <= 0) {