From 8b3c51f1eb585bcd175323f250190ed1fc7540f5 Mon Sep 17 00:00:00 2001
From: Tieqiong Zhang <tz2600@columbia.edu>
Date: Wed, 5 Feb 2025 16:50:33 -0500
Subject: [PATCH] fix: fix TypeError when using Nyquist interp

---
 news/interp_xtype.rst                   | 23 +++++++++++++++++++++++
 src/diffpy/pdfgui/control/fitdataset.py |  3 +++
 2 files changed, 26 insertions(+)
 create mode 100644 news/interp_xtype.rst

diff --git a/news/interp_xtype.rst b/news/interp_xtype.rst
new file mode 100644
index 00000000..094877bf
--- /dev/null
+++ b/news/interp_xtype.rst
@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Fixed TypeError when using Nyquist interp.
+
+**Security:**
+
+* <news item>
diff --git a/src/diffpy/pdfgui/control/fitdataset.py b/src/diffpy/pdfgui/control/fitdataset.py
index 559e9dbd..11c490d7 100644
--- a/src/diffpy/pdfgui/control/fitdataset.py
+++ b/src/diffpy/pdfgui/control/fitdataset.py
@@ -848,6 +848,9 @@ def grid_interpolation(x0, y0, x1, left=None, right=None, tp=None):
     Otherwise it uses the internal :func:`_linear_interpolation` routine.
     """
     if tp == "Nyquist":
+        x0 = numpy.asarray(x0)
+        x1 = numpy.asarray(x1)
+        y0 = numpy.asarray(y0)
         return wsinterp(x1, x0, y0, left, right)
     else:
         left = 0.0 if left is None else left