diff --git a/wafo/misc.py b/wafo/misc.py
index cce43d8..484de8a 100644
--- a/wafo/misc.py
+++ b/wafo/misc.py
@@ -2916,7 +2916,7 @@ def _histogram(data, bins=None, range=None, normed=False, weights=None,
     """
     x = np.atleast_1d(data)
     if bins is None:
-        bins = np.ceil(4 * np.sqrt(np.sqrt(len(x))))
+        bins = int(np.ceil(4 * np.sqrt(np.sqrt(len(x)))))
     bin_, limits = np.histogram(data, bins=bins, range=range, normed=normed,
                                 weights=weights, density=density)
     xx, yy = _make_bars(limits, bin_)
diff --git a/wafo/spectrum/core.py b/wafo/spectrum/core.py
index 16e111b..b51d1ff 100644
--- a/wafo/spectrum/core.py
+++ b/wafo/spectrum/core.py
@@ -578,7 +578,7 @@ class SpecData1D(PlotData):
         if dt is None:
             return dt_old, 1
         rate = max(round(dt_old * 1. / dt), 1.)
-        return dt, rate
+        return dt, int(rate)
 
     def _check_dt(self, dt):
         freq = self.args
@@ -659,9 +659,9 @@ class SpecData1D(PlotData):
         n_f = len(freq)
         if nt is None:
             nt = rate * (n_f - 1)
-        else:  # %check if Nt is ok
+        else:  # check if Nt is ok
             nt = minimum(nt, rate * (n_f - 1))
-
+        # nr, nt = int(nr), int(nt)
         spec = self.copy()
         spec.resample(dt)