class_docstr: Bounding box anchor generator for Single-shot Object Detection, corresponding to anchors
  structure used in ssd_mobilenet_v1_coco from TF Object Detection API
  This class inherits SSDAnchorGenerator and uses the same input parameters.
  Main differences:
    - First branch is not added with another anchor with size extracted from
      the geomtric mean of current and next branch sizes.
    - First anchor in the first branch has half the size of the rest of the anchors.
    - Geometric sum anchors are added to all other branches as the last anchor.
class_docstr_tok: ["Bounding","box","anchor","generator","for","Single-shot","Object","Detection",",","corresponding","to","anchors","structure","used","in","ssd_mobilenet_v1_coco","from","TF","Object","Detection","API","This","class","inherits","SSDAnchorGenerator","and","uses","the","same","input","parameters",".","Main","differences",":","-","First","branch","is","not","added","with","another","anchor","with","size","extracted","from","the","geomtric","mean","of","current","and","next","branch","sizes",".","-","First","anchor","in","the","first","branch","has","half","the","size","of","the","rest","of","the","anchors",".","-","Geometric","sum","anchors","are","added","to","all","other","branches","as","the","last","anchor","."]
docstr: Number of anchors at each pixel.
docstr_tok: ["Number","of","anchors","at","each","pixel","."]
code: def num_depth(self):
      """Number of anchors at each pixel."""
      if self._index == 0:
          return len(self._ratios)
      else:
          return len(self._sizes) + len(self._ratios) - 1
  
file_path: gluon-cv/gluoncv/model_zoo/ssd/anchor.py
imports: from __future__ import absolute_import
  import numpy
  from mxnet import gluon
label_desc: Use image node_id 2 for calling the LiteAnchorGenerator obj's underlying member method code with example usage: obj.num_depth() and returns: len, unknown