fix(Gridder): consistent use of Gridder.SetResolution

CHANGES.txt

@@ -1,3 +1,5 @@
+* add Gridder1D.SetResolution and use it more consistently in all Gridder
+
 v1.8.0, 2026-07-21
 
 * replace deprecated scipy.odr usage with direct odrpack calls

lib/xrayutilities/gridder.py

@@ -131,6 +131,15 @@ def __call__(self):
         override
         """
 
+    def SetResolution(self, *resolution):
+        """
+        Reset the grid resolution and discard currently gridded data.
+
+        The number of resolution arguments depends on the dimensionality of the
+        concrete gridder.
+        """
+        raise NotImplementedError
+
     def Normalize(self, bool):
         """
         set or unset the normalization flag.  Normalization needs to be done to
@@ -187,14 +196,16 @@ def Clear(self):
 class Gridder1D(Gridder):
     def __init__(self, nx):
         Gridder.__init__(self)
-        if nx <= 0:
-            raise InputError("nx must be a positiv integer!")
-
-        self.nx = nx
         self.xmin = 0
         self.xmax = 0
-        self._gdata = numpy.zeros(nx, dtype=numpy.double)
-        self._gnorm = numpy.zeros(nx, dtype=numpy.double)
+        self.SetResolution(nx)
+
+    def _allocate_memory(self):
+        """
+        Allocate data and normalization arrays for the current resolution.
+        """
+        self._gdata = numpy.zeros(self.nx, dtype=numpy.double)
+        self._gnorm = numpy.zeros(self.nx, dtype=numpy.double)
 
     def savetxt(self, filename, header=""):
         """
@@ -215,6 +226,22 @@ def savetxt(self, filename, header=""):
             fmt="%.6g %.4g",
         )
 
+    def SetResolution(self, nx):
+        """
+        Reset the 1D grid resolution and discard currently gridded data.
+
+        Parameters
+        ----------
+        nx :    int
+            Number of points in x-direction.
+        """
+        if nx <= 0:
+            raise InputError("nx must be a positive integer!")
+
+        self.nx = nx
+
+        self._allocate_memory()
+
     def __get_xaxis(self):
         """
         Returns the xaxis of the gridder

lib/xrayutilities/gridder2d.py

@@ -28,26 +28,16 @@ class Gridder2D(Gridder):
     def __init__(self, nx, ny):
         Gridder.__init__(self)
 
-        # check input
-        if nx <= 0 or ny <= 0:
-            raise exception.InputError(
-                "Neither nx nor ny can be smallerthan 1!"
-            )
-
         self.xmin = None
         self.ymin = None
         self.xmax = None
         self.ymax = None
 
-        self.nx = nx
-        self.ny = ny
-
-        self._allocate_memory()
+        self.SetResolution(nx, ny)
 
     def _allocate_memory(self):
         """
-        Class method to allocate memory for the gridder based on the nx, ny
-        class attributes.
+        Allocate data and normalization arrays for the current resolution.
         """
 
         self._gdata = numpy.zeros((self.nx, self.ny), dtype=numpy.double)
@@ -77,16 +67,20 @@ def savetxt(self, filename, header=""):
 
     def SetResolution(self, nx, ny):
         """
-        Reset the resolution of the gridder. In this case the original data
-        stored in the object will be deleted.
+        Reset the 2D grid resolution and discard currently gridded data.
 
         Parameters
         ----------
-        nx :	 int
-            number of points in x-direction
-        ny :	 int
-            number of points in y-direction
+        nx :    int
+            Number of points in x-direction.
+        ny :    int
+            Number of points in y-direction.
         """
+        if nx <= 0 or ny <= 0:
+            raise exception.InputError(
+                "Neither nx nor ny can be smaller than 1!"
+            )
+
         self.nx = nx
         self.ny = ny
 

lib/xrayutilities/gridder3d.py

@@ -28,29 +28,18 @@ class Gridder3D(Gridder):
     def __init__(self, nx, ny, nz):
         Gridder.__init__(self)
 
-        # check input
-        if nx <= 0 or ny <= 0 or nz <= 0:
-            raise exception.InputError(
-                "None of nx, ny and nz can be smaller than 1!"
-            )
-
         self.xmin = 0
         self.xmax = 0
         self.ymin = 0
         self.ymax = 0
         self.zmin = 0
         self.zmax = 0
 
-        self.nx = nx
-        self.nz = nz
-        self.ny = ny
-
-        self._allocate_memory()
+        self.SetResolution(nx, ny, nz)
 
     def _allocate_memory(self):
         """
-        Class method to allocate memory for the gridder based on the nx, ny
-        class attributes.
+        Allocate data and normalization arrays for the current resolution.
         """
         self._gdata = numpy.zeros(
             (self.nx, self.ny, self.nz), dtype=numpy.double
@@ -60,6 +49,23 @@ class attributes.
         )
 
     def SetResolution(self, nx, ny, nz):
+        """
+        Reset the 3D grid resolution and discard currently gridded data.
+
+        Parameters
+        ----------
+        nx :    int
+            Number of points in x-direction.
+        ny :    int
+            Number of points in y-direction.
+        nz :    int
+            Number of points in z-direction.
+        """
+        if nx <= 0 or ny <= 0 or nz <= 0:
+            raise exception.InputError(
+                "None of nx, ny and nz can be smaller than 1!"
+            )
+
         self.nx = nx
         self.ny = ny
         self.nz = nz

tests/test_gridder1d.py

@@ -19,6 +19,7 @@
 
 import numpy
 import xrayutilities as xu
+from xrayutilities.exception import InputError
 
 
 class TestGridder1D(unittest.TestCase):
@@ -48,6 +49,21 @@ def test_gridder1d_data(self):
                 self.gridder.data[i], self.data[i], places=12
             )
 
+    def test_gridder1d_set_resolution(self):
+        gridder = xu.Gridder1D(self.num)
+        gridder(self.x, self.data)
+
+        new_num = self.num + 7
+        gridder.SetResolution(new_num)
+
+        self.assertEqual(gridder.nx, new_num)
+        self.assertEqual(gridder.data.shape, (new_num,))
+        self.assertTrue(numpy.all(gridder.data == 0))
+
+    def test_gridder1d_set_resolution_invalid(self):
+        with self.assertRaises(InputError):
+            xu.Gridder1D(self.num).SetResolution(0)
+
 
 if __name__ == "__main__":
     unittest.main()