def mmd_loss_laplacian()

in agents/bc_mmd.py [0:0]

• 9 lines of code
• 4 McCabe index (conditional complexity)

    def mmd_loss_laplacian(self, samples1, samples2, sigma=0.2):
        """MMD constraint with Laplacian kernel for support matching"""
        # sigma is set to 10.0 for hopper, cheetah and 20 for walker/ant
        diff_x_x = samples1.unsqueeze(2) - samples1.unsqueeze(1)  # B x N x N x d
        diff_x_x = torch.mean((-(diff_x_x.abs()).sum(-1) / (2.0 * sigma)).exp(), dim=(1, 2))

        diff_x_y = samples1.unsqueeze(2) - samples2.unsqueeze(1)
        diff_x_y = torch.mean((-(diff_x_y.abs()).sum(-1) / (2.0 * sigma)).exp(), dim=(1, 2))

        diff_y_y = samples2.unsqueeze(2) - samples2.unsqueeze(1)  # B x N x N x d
        diff_y_y = torch.mean((-(diff_y_y.abs()).sum(-1) / (2.0 * sigma)).exp(), dim=(1, 2))

        overall_loss = (diff_x_x + diff_y_y - 2.0 * diff_x_y + 1e-6).sqrt()
        return overall_loss