Merge pull request #2 from myokit/imin-imax

Added imin and imax methods.

datkit/__init__.py

@@ -49,6 +49,8 @@
 
 from ._points import (  # noqa
     abs_max_on,
+    imax_on,
+    imin_on,
     index,
     index_near,
     index_on,

datkit/_points.py

@@ -13,7 +13,7 @@ def abs_max_on(times, values, t0=None, t1=None, include_left=True,
                include_right=False):
     """
     Returns a tuple ``(t_max, v_max)`` corresponding to the maximum value in
-    ``values`` on the interval from ``t0`` to ``t1``.
+    ``abs(values)`` on the interval from ``t0`` to ``t1``.
 
     See also :meth:`index_on`.
     """
@@ -22,6 +22,30 @@ def abs_max_on(times, values, t0=None, t1=None, include_left=True,
     return times[i], values[i]
 
 
+def imax_on(times, values, t0=None, t1=None, include_left=True,
+            include_right=False):
+    """
+    Returns the index ``i`` corresponding to the maximum value on the interval
+    from ``t0`` to ``t1``.
+
+    See also :meth:`index_on`.
+    """
+    i, j = index_on(times, t0, t1, include_left, include_right)
+    return i + np.argmax(values[i:j])
+
+
+def imin_on(times, values, t0=None, t1=None, include_left=True,
+            include_right=False):
+    """
+    Returns the index ``i`` corresponding to the maximum value on the interval
+    from ``t0`` to ``t1``.
+
+    See also :meth:`index_on`.
+    """
+    i, j = index_on(times, t0, t1, include_left, include_right)
+    return i + np.argmin(values[i:j])
+
+
 def index(times, t, ttol=1e-9):
     """
     Returns the index of time ``t`` in ``times``.

datkit/_smoothing.py

@@ -44,7 +44,8 @@ def haar_downsample(times, values, repeats=1):
     - If the signal length is odd, the final sample is omitted
     - The first two samples are averaged, then the next two, etc.
 
-    Returns a new and downsampled time series ``(times_2, values_2)``.
+    Returns a new and downsampled time series ``(times_2, values_2)`` of length
+    ``len(times) // 2**repeats``.
     """
     times, values = np.asarray(times), np.asarray(values)
     if len(times) != len(values):
@@ -98,7 +99,7 @@ def window_size(times, w=None, t=None):
         dt = d.sampling_interval(times)
         if t / dt < 2.9:
             raise ValueError(
-                'Invalid window size: must be at least 3 times the samplig'
+                'Invalid window size: must be at least 3 times the sampling'
                 f' interval {dt}.')
 
         w = int(1 + 2 * ((t / dt) // 2))

datkit/tests/test_points.py

@@ -25,6 +25,24 @@ def test_abs_max_on(self):
         self.assertEqual(d.abs_max_on(t, v, 1.5, 2), (t[99], v[99]))
         self.assertEqual(d.abs_max_on(t, v, 1.5, 2, False, True), (2, 1))
 
+    def test_imax_on(self):
+        t = np.linspace(0, 2, 101)
+        v = np.cos(t * np.pi)
+        self.assertEqual(d.imax_on(t, v, 0, 1), 0)
+        self.assertEqual(d.imax_on(t, v, 0.5, 1), 25)
+        self.assertEqual(d.imax_on(t, v, 0.6, 1.5), 74)
+        self.assertEqual(d.imax_on(t, v, 1.5, 2), 99)
+        self.assertEqual(d.imax_on(t, v, 1.5, 2, False, True), 100)
+
+    def test_imin_on(self):
+        t = np.linspace(0, 2, 101)
+        v = np.cos(t * np.pi)
+        self.assertEqual(d.imin_on(t, v, 0, 1), 49)
+        self.assertEqual(d.imin_on(t, v, 0.5, 2), 50)
+        self.assertEqual(d.imin_on(t, v, 0.5, 1.5), 50)
+        self.assertEqual(d.imin_on(t, v, 1.5, 2), 75)
+        self.assertEqual(d.imin_on(t, v, 1.5, 2, False), 76)
+
     def test_index(self):
 
         # Simple tests
@@ -164,7 +182,6 @@ def test_index_on(self):
 
         # Values not specified
         t = np.arange(0, 20, 2)
-        print(t)
         self.assertEqual(d.index_on(t), (0, 10))
         self.assertEqual(d.index_on(t, include_left=False), (0, 10))
         self.assertEqual(d.index_on(t, include_right=True), (0, 10))

docs/source/finding_points.rst

@@ -22,3 +22,7 @@ Finding points
 
 .. autofunction:: abs_max_on
 
+.. autofunction:: imax_on
+
+.. autofunction:: imin_on
+

docs/source/index.rst

@@ -1,10 +1,11 @@
-************
-Introduction
-************
+*****************
+Table of contents
+*****************
 
 .. module:: datkit
 
-Some silly scripts to do stuff I do all the time.
+This module contains some simple methods that are useful when analysing time
+series data.
 
 ..  toctree::