enhance/add histogram sample

visualdl/server/lib.py

@@ -133,7 +133,7 @@ def get_invididual_image(storage, mode, tag, step_index, max_size=80):
  shape = record.shape()
 
  if shape[2] == 1:
- shape = [shape[0], shape[1]]
+  shape = [shape[0], shape[1]]
  data = np.array(record.data(), dtype='uint8').reshape(shape)
  tempfile = NamedTemporaryFile(mode='w+b', suffix='.png')
  with Image.fromarray(data) as im:
@@ -146,7 +146,7 @@ def get_histogram_tags(storage):
  return get_tags(storage, 'histogram')
 
 
-def get_histogram(storage, mode, tag):
+def get_histogram(storage, mode, tag, num_samples=200):
  with storage.mode(mode) as reader:
  histogram = reader.histogram(tag)
  res = []
@@ -171,7 +171,21 @@ def get_histogram(storage, mode, tag):
  [instance.left(),
  instance.right(),
  instance.frequency()])
- return res
+ if len(res) < num_samples:
+ return res
+
+ # sample some steps
+ span = float(len(res)) / (num_samples - 1)
+ span_offset = 0
+ data_idx = 0
+
+ sampled_data = []
+ while data_idx < num_samples:
+ sampled_data.append(res[len(res) - data_idx - 1])
+ span_offset += 1
+ data_idx = int(span_offset * span)
+ sampled_data.append(res[0])
+ return sampled_data[::-1]
 
 
 if __name__ == '__main__':