class_docstr: modified from https://github.com/jorge-pessoa/pytorch-msssim
class_docstr_tok: ["modified","from","https",":","\/\/github.com\/jorge-pessoa\/pytorch-msssim"]
code: def gaussian(self, w_size, sigma):
      gauss = torch.Tensor(
          [
              math.exp(
                  -((x - w_size // 2) ** 2) / float(2 * sigma**2)
              )
              for x in range(w_size)
          ]
      )
      return gauss / gauss.sum()
  
imports: import math
  import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 3 for calling the SSIM obj's underlying member method code with example usage: obj.gaussian(w_size, sigma) and returns: unknown