* Added function get_n_cyc_array to compute number of cycles series…

… from a loading series

HISTORY.rst

@@ -7,6 +7,7 @@ History
 
 * Fixed issue in `get_zero_crossings_array_indices` where it would fail if array did not contain any zeros.
 * Added calculation of equivalent number of cycles and equivalent uniform amplitude using power law relationship as intensity measures
+* Added function `get_n_cyc_array` to compute number of cycles series from a loading series
 
 
 1.1.0 (2019-10-08)

eqsig/functions.py

@@ -138,6 +138,38 @@ def get_peak_array_indices(values, ptype='all'):
     return peak_full_indices
 
 
+def get_n_cyc_array(values, opt='all', start='origin'):
+    """
+    Given an array, create an array of the same length that numbers the peaks
+    Parameters
+    ----------
+    values
+    opt
+
+    Returns
+    -------
+
+    """
+    if opt == 'all':
+        indys = get_peak_array_indices(values)
+    elif opt == 'switched':
+        indys = get_switched_peak_array_indices(values)
+    else:
+        raise ValueError('opt must be either "all" or "switched"')
+    # each indy corresponds to half a cycle
+    if start == 'origin':
+        svalue = -0.25
+    elif start == 'peak':
+        svalue = 0.0
+    else:
+        raise ValueError('start must be either "origin" or "peak"')
+    if indys[0] != 0:
+        indys = np.insert(indys, 0, 0)
+    n_cycs = 0.5 * np.arange(len(indys))
+    n_cycs[1:] += svalue
+    return np.interp(np.arange(len(values)), indys, n_cycs)
+
+
 def get_peak_indices(asig):
     return get_peak_array_indices(asig.values)
 

tests/test_functions.py

@@ -167,6 +167,17 @@ def test_get_peak_indices():
     expected = np.array([0, 1, 2, 3, 4, 5, 8, 10, 11])
     assert np.sum(abs(peak_indices - expected)) == 0
 
+    values = np.array([2, 1, -1, 1])
+    peak_indices = fns.get_peak_array_indices(values)
+    expected = np.array([0, 2, 3])
+    assert np.sum(abs(peak_indices - expected)) == 0
+
+    values = np.array([1, 2, -1, 1])
+    peak_indices = fns.get_peak_array_indices(values)
+    expected = np.array([0, 1, 2, 3])
+    assert np.sum(abs(peak_indices - expected)) == 0
+
+
 
 def test_get_zero_crossings_array_indices():
     vs = np.array([0, 2, 1, 2, -1, 1, 0, 0, 1, 0.3, 0, -1, 0.2, 1, 0.2])
@@ -272,7 +283,7 @@ def test_roll_av_vals():
 
 if __name__ == '__main__':
 
-    test_get_zero_crossings_array_indices2()
+    test_get_peak_indices()
     # test_put_array_in_2d_array()
     # test_fa_spectrum_conversion()
     # test_determine_peaks_only_series_with_sine_wave()