writer = SummaryWriter("my_experiment")
         # folder location: my_experiment
     # create a summary writer with comment appended.
     writer = SummaryWriter(comment="LR_0.1_BATCH_16")
     # folder location: runs/May04_22-14-54_s-MacBook-Pro.localLR_0.1_BATCH_16/

add_scalar(tag, scalar_value, global_step=None, walltime=None, new_style=False, double_precision=False)
  Add scalar data to summary.

  Parameters:
     * **tag** (*str*) -- Data identifier

     * **scalar_value** (*float** or **string/blobname*) -- Value
       to save

     * **global_step** (*int*) -- Global step value to record

     * **walltime** (*float*) -- Optional override default
       walltime (time.time()) with seconds after epoch of event

     * **new_style** (*boolean*) -- Whether to use new style
       (tensor field) or old style (simple_value field). New style
       could lead to faster data loading.

  Examples:
