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Delete unused positional embedding functions
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Natyren authored Jul 18, 2023
1 parent 615a44f commit b0f8b21
Showing 1 changed file with 0 additions and 63 deletions.
63 changes: 0 additions & 63 deletions lightly/models/modules/ijepa.py
Original file line number Diff line number Diff line change
Expand Up @@ -431,66 +431,3 @@ def images_to_tokens(
if prepend_class_token:
tokens = utils.prepend_class_token(tokens, self.class_token)
return tokens


def _get_2d_sincos_pos_embed(embed_dim, grid_size, cls_token=False):
"""
grid_size: int of the grid height and width
return:
pos_embed: [grid_size*grid_size, embed_dim] or [1+grid_size*grid_size, embed_dim] (w/ or w/o cls_token)
"""
grid_h = np.arange(grid_size, dtype=float)
grid_w = np.arange(grid_size, dtype=float)
grid = np.meshgrid(grid_w, grid_h) # here w goes first
grid = np.stack(grid, axis=0)

grid = grid.reshape([2, 1, grid_size, grid_size])
pos_embed = _get_2d_sincos_pos_embed_from_grid(embed_dim, grid)
if cls_token:
pos_embed = np.concatenate([np.zeros([1, embed_dim]), pos_embed], axis=0)
return pos_embed


def _get_2d_sincos_pos_embed_from_grid(embed_dim, grid):
assert embed_dim % 2 == 0

# use half of dimensions to encode grid_h
emb_h = _get_1d_sincos_pos_embed_from_grid(embed_dim // 2, grid[0]) # (H*W, D/2)
emb_w = _get_1d_sincos_pos_embed_from_grid(embed_dim // 2, grid[1]) # (H*W, D/2)

emb = np.concatenate([emb_h, emb_w], axis=1) # (H*W, D)
return emb


def _get_1d_sincos_pos_embed(embed_dim, grid_size, cls_token=False):
"""
grid_size: int of the grid length
return:
pos_embed: [grid_size, embed_dim] or [1+grid_size, embed_dim] (w/ or w/o cls_token)
"""
grid = np.arange(grid_size, dtype=float)
pos_embed = _get_1d_sincos_pos_embed_from_grid(embed_dim, grid)
if cls_token:
pos_embed = np.concatenate([np.zeros([1, embed_dim]), pos_embed], axis=0)
return pos_embed


def _get_1d_sincos_pos_embed_from_grid(embed_dim, pos):
"""
embed_dim: output dimension for each position
pos: a list of positions to be encoded: size (M,)
out: (M, D)
"""
assert embed_dim % 2 == 0
omega = np.arange(embed_dim // 2, dtype=float)
omega /= embed_dim / 2.0
omega = 1.0 / 10000**omega # (D/2,)

pos = pos.reshape(-1) # (M,)
out = np.einsum("m,d->md", pos, omega) # (M, D/2), outer product

emb_sin = np.sin(out) # (M, D/2)
emb_cos = np.cos(out) # (M, D/2)

emb = np.concatenate([emb_sin, emb_cos], axis=1) # (M, D)
return emb

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