stop reading many frames to get times for shifted_correlation

src/mdevaluate/coordinates.py

@@ -413,7 +413,6 @@ def center_of_masses(
 ) -> NDArray:
     if atom_indices is None:
         atom_indices = list(range(len(frame)))
-    print(type(frame))
     res_ids = frame.residue_ids[atom_indices]
     masses = frame.masses[atom_indices]
     if shear:

src/mdevaluate/correlation.py

@@ -147,7 +147,8 @@ def shifted_correlation(
     num_frames = int(len(frames) * window)
     ls = np.logspace(0, np.log10(num_frames + 1), num=points)
     idx = np.unique(np.int_(ls) - 1)
-    t = np.array([frames[i].time for i in idx]) - frames[0].time
+    dt = round(frames[1].time - frames[0].time, 6) # round to avoid bad floats
+    t = idx * dt
 
     result = np.array(
         [