Merge pull request #417 from CPJKU/scipy_derivative_deprecation

Replaced deprecated scipy derivative

partitura/musicanalysis/performance_codec.py

@@ -14,9 +14,9 @@
 from partitura.performance import PerformedPart, PerformanceLike
 from partitura.musicanalysis import note_features
 from partitura.utils.misc import deprecated_alias
-from partitura.utils.generic import interp1d, monotonize_times
+from partitura.utils.generic import interp1d, monotonize_times, first_order_derivative
 from partitura.utils.music import ensure_notearray
-from scipy.misc import derivative
+
 
 __all__ = ["encode_performance", "decode_performance", "to_matched_score"]
 
@@ -595,7 +595,7 @@ def tempo_by_derivative(
     if input_onsets is None:
         input_onsets = unique_s_onsets[:-1]
 
-    tempo_curve = derivative(onset_fun, input_onsets, dx=0.5)
+    tempo_curve = first_order_derivative(onset_fun, input_onsets, dx=0.5)
 
     if return_onset_idxs:
         return tempo_curve, input_onsets, unique_onset_idxs

partitura/utils/generic.py

@@ -171,6 +171,38 @@ def iter_subclasses(cls, _seen=None):
                 yield sub
 
 
+def first_order_derivative(func, x0, dx=0.5):
+    """
+    Compute the first order derivative of a function at a point `x0` using
+    a central difference scheme. This function is an adaptation of the scipy _derivative
+    function, which is no longer available in the public API after version 1.15.
+    More information can be found at:
+    https://github.com/scipy/scipy/blob/v1.7.0/scipy/misc/common.py#L75-L145
+
+    Parameters
+    ----------
+    func: callable
+        Function to differentiate
+    x0: np.ndarray
+        Points at which to differentiate
+    dx: float
+        Step size
+
+    Returns
+    -------
+    np.ndarray
+        First order derivative of `func` at `x0`
+    """
+    # fixed number of points to use, must be odd.
+    num_points = 3
+    weights = np.array([-1, 0, 1]) / 2.0
+    val = 0.0
+    ho = num_points >> 1
+    for k in range(num_points):
+        val += weights[k] * func(x0 + (k - ho) * dx)
+    return val / dx
+
+
 class ReplaceRefMixin(object):
     """This class is a utility mixin class to replace references to
     objects with references to other objects. This is functionality is