ref: use negative indexing for np array shape

qpretrieve/fourier/base.py

@@ -243,15 +243,15 @@ def filter(self, filter_name: str, filter_size: float,
                 # only take shape of a single fft
                 fft_shape=self.fft_origin.shape[-2:])
             fft_filtered = self.fft_origin * filt_array
-            px = int(freq_pos[0] * self.shape[0])
-            py = int(freq_pos[1] * self.shape[1])
+            px = int(freq_pos[0] * self.shape[-2])
+            py = int(freq_pos[1] * self.shape[-1])
             fft_used = np.roll(np.roll(fft_filtered, -px, axis=0), -py, axis=1)
             if scale_to_filter:
                 # Determine the size of the cropping region.
                 # We compute the "radius" of the region, so we can
                 # crop the data left and right from the center of the
                 # Fourier domain.
-                osize = fft_filtered.shape[0]  # square shaped
+                osize = fft_filtered.shape[-2]  # square shaped
                 crad = int(np.ceil(filter_size * osize * scale_to_filter))
                 ccent = osize // 2
                 cslice = slice(ccent - crad, ccent + crad)

qpretrieve/interfere/base.py

@@ -121,13 +121,13 @@ def compute_filter_size(self, filter_size, filter_size_interpretation,
             # filter size given in Fourier index (number of Fourier pixels)
             # The user probably does not know that we are padding in
             # Fourier space, so we use the unpadded size and translate it.
-            if filter_size <= 0 or filter_size >= self.fft.shape[0] / 2:
+            if filter_size <= 0 or filter_size >= self.fft.shape[-2] / 2:
                 raise ValueError("For frequency index interpretation, "
                                  + "`filter_size` must be between 0 and "
-                                 + f"{self.fft.shape[0] / 2}, got "
+                                 + f"{self.fft.shape[-2] / 2}, got "
                                  + f"'{filter_size}'!")
             # convert to frequencies (compatible with fx and fy)
-            fsize = filter_size / self.fft.shape[0]
+            fsize = filter_size / self.fft.shape[-2]
         else:
             raise ValueError("Invalid value for `filter_size_interpretation`: "
                              + f"'{filter_size_interpretation}'")