math

+""" Mathematical formulae for different expressions"""
+
+import torch
+
+from .torch_utils import EPSILON
+
+
+def echo_mi(f, s):
+    N = s.shape[0]
+    s = s.view(N, -1)
+    return -torch.log(torch.abs(s) + EPSILON).sum(dim=1)
+
+
+def get_echo_clip_factor(num_samples):
+    max_fx = 1
+    d_max = num_samples
+
+    return (2 ** (-23) / max_fx) ** (1.0 / d_max)