From d2b1ecbb23f6d2f6148ad585992d989c36c7c8e1 Mon Sep 17 00:00:00 2001
From: dwarning <dietmar.warning@gmail.com>
Date: Sun, 1 Mar 2026 16:18:24 +0100
Subject: [PATCH] correct fft scaling at Nyquist freq. in fft cmd and vector
 operation

---
 src/frontend/com_fft.c    | 4 +++-
 src/maths/cmaths/cmath4.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/frontend/com_fft.c b/src/frontend/com_fft.c
index baefb2c51..b06d1e37d 100644
--- a/src/frontend/com_fft.c
+++ b/src/frontend/com_fft.c
@@ -181,10 +181,12 @@ com_fft(wordlist *wl)
         scale = (double) fpts - 1.0;
         fdvec[i][0].cx_real = out[0][0]/scale/2.0;
         fdvec[i][0].cx_imag = 0.0;
-        for (j = 1; j < fpts; j++) {
+        for (j = 1; j < fpts-1; j++) {
             fdvec[i][j].cx_real = out[j][0]/scale;
             fdvec[i][j].cx_imag = out[j][1]/scale;
         }
+        fdvec[i][fpts-1].cx_real = out[fpts-1][0]/scale/2.0;
+        fdvec[i][fpts-1].cx_imag = 0.0;
 
     }
 
diff --git a/src/maths/cmaths/cmath4.c b/src/maths/cmaths/cmath4.c
index c29e53634..92cfe458a 100644
--- a/src/maths/cmaths/cmath4.c
+++ b/src/maths/cmaths/cmath4.c
@@ -777,10 +777,12 @@ cx_fft(void *data, short int type, int length, int *newlength, short int *newtyp
         scale = (double) fpts - 1.0;
         outdata[0].cx_real = out[0][0]/scale/2.0;
         outdata[0].cx_imag = 0.0;
-        for (i = 1; i < fpts; i++) {
+        for (i = 1; i < fpts-1; i++) {
             outdata[i].cx_real = out[i][0]/scale;
             outdata[i].cx_imag = out[i][1]/scale;
         }
+        outdata[fpts-1].cx_real = out[fpts-1][0]/scale/2.0;
+        outdata[fpts-1].cx_imag = 0.0;
 
         fftw_free(ind);