title: find_peaks does not identify a peak at the start of the array
body: <p>I am trying to find a vectorized approach of finding the first position in an array where the values did not get higher than the maximum of n previous numbers. I thought about using the find_peaks method of scipy.signal to find a local maximum. I think it does exactly that if you define the distance to let's say 10 n is 10. But unfortunately, the condition for the distance has to be fulfilled in both directions - previous and upcoming numbers. Is there any other method or approach to finding such a thing?</p>
  
  <p><strong>Example:</strong></p>
  
  <pre><code>arr1 = np.array([1.        , 0.73381293, 0.75649351, 0.77693474, 0.77884614,
         0.81055903, 0.81402439, 0.78798586, 0.78839588, 0.82967961,
         0.8448    , 0.83276451, 0.82539684, 0.81762916, 0.82722515,
         0.82101804, 0.82871127, 0.82825041, 0.82086957, 0.8347826 ,
         0.82666665, 0.82352942, 0.81270903, 0.81191224, 0.83180428,
         0.84975767, 0.84044236, 0.85057473, 0.8394649 , 0.80000001,
         0.83870965, 0.83962262, 0.85039371, 0.83359748, 0.84019768,
         0.83281732, 0.83660132])
  
  from scipy.signal import find_peaks
  peaks, _ = find_peaks(arr1, distance=10)
  </code></pre>
  
  <p>In this case, it finds positions 10 and 27. But also position 0 has 10 following elements which are not higher. How can I find those?</p>