Added multimer changes for loss functions

openfold/config.py

@@ -648,6 +648,7 @@ config = mlc.ConfigDict(
             "violation": {
                 "violation_tolerance_factor": 12.0,
                 "clash_overlap_tolerance": 1.5,
+                "average_clashes": False,
                 "eps": eps,  # 1e-6,
                 "weight": 0.0,
             },
@@ -660,6 +661,12 @@ config = mlc.ConfigDict(
                 "weight": 0.,
                 "enabled": tm_enabled,
             },
+            "chain_center_of_mass": {
+                "clamp_distance": -4.0,
+                "weight": 0.,
+                "eps": eps,
+                "enabled": False,
+            },
             "eps": eps,
         },
         "ema": {"decay": 0.999},
@@ -802,7 +809,9 @@ multimer_model_config_update = {
         "tm": {
             "c_z": c_z,
             "no_bins": aux_distogram_bins,
-            "enabled": tm_enabled,
+            "ptm_weight": 0.2,
+            "iptm_weight": 0.8,
+            "enabled": True,
         },
         "masked_msa": {
             "c_m": c_m,
@@ -813,5 +822,81 @@ multimer_model_config_update = {
             "c_out": 37,
         },
     },
+    "loss": {
+        "distogram": {
+            "min_bin": 2.3125,
+            "max_bin": 21.6875,
+            "no_bins": 64,
+            "eps": eps,  # 1e-6,
+            "weight": 0.3,
+        },
+        "experimentally_resolved": {
+            "eps": eps,  # 1e-8,
+            "min_resolution": 0.1,
+            "max_resolution": 3.0,
+            "weight": 0.0,
+        },
+        "fape": {
+            "intra_chain_backbone": {
+                "clamp_distance": 10.0,
+                "loss_unit_distance": 10.0,
+                "weight": 0.5,
+            },
+            "interface": {
+                "clamp_distance": 30.0,
+                "loss_unit_distance": 20.0,
+                "weight": 0.5,
+            },
+            "sidechain": {
+                "clamp_distance": 10.0,
+                "length_scale": 10.0,
+                "weight": 0.5,
+            },
+            "eps": 1e-4,
+            "weight": 1.0,
+        },
+        "plddt_loss": {
+            "min_resolution": 0.1,
+            "max_resolution": 3.0,
+            "cutoff": 15.0,
+            "no_bins": 50,
+            "eps": eps,  # 1e-10,
+            "weight": 0.01,
+        },
+        "masked_msa": {
+            "num_classes": 23,
+            "eps": eps,  # 1e-8,
+            "weight": 2.0,
+        },
+        "supervised_chi": {
+            "chi_weight": 0.5,
+            "angle_norm_weight": 0.01,
+            "eps": eps,  # 1e-6,
+            "weight": 1.0,
+        },
+        "violation": {
+            "violation_tolerance_factor": 12.0,
+            "clash_overlap_tolerance": 1.5,
+            "average_clashes": True,
+            "eps": eps,  # 1e-6,
+            "weight": 0.03, # Not finetuning
+        },
+        "tm": {
+            "max_bin": 31,
+            "no_bins": 64,
+            "min_resolution": 0.1,
+            "max_resolution": 3.0,
+            "eps": eps,  # 1e-8,
+            "weight": 0.1,
+            "enabled": True,
+        },
+        "chain_center_of_mass": {
+            "clamp_distance": -4.0,
+            "weight": 0.05,
+            "eps": eps,
+            "enabled": True,
+        },
+        "eps": eps,
+    },
     "recycle_early_stop_tolerance": 0.5
 }

openfold/model/heads.py

@@ -76,9 +76,17 @@ class AuxiliaryHeads(nn.Module):
         if self.config.tm.enabled:
             tm_logits = self.tm(outputs["pair"])
             aux_out["tm_logits"] = tm_logits
-            aux_out["predicted_tm_score"] = compute_tm(
+            aux_out["ptm_score"] = compute_tm(
                 tm_logits, **self.config.tm
             )
+            asym_id = outputs.get("asym_id")
+            if asym_id is not None:
+                aux_out["iptm_score"] = compute_tm(
+                    tm_logits, asym_id=asym_id, interface=True, **self.config.tm
+                )
+                aux_out["weighted_ptm_score"] = (self.config.tm["iptm_weight"] * aux_out["iptm_score"]
+                                                 + self.config.tm["ptm_weight"] * aux_out["ptm_score"])
+
             aux_out.update(
                 compute_predicted_aligned_error(
                     tm_logits,

openfold/model/model.py

@@ -555,6 +555,9 @@ class AlphaFold(nn.Module):
                 else:
                     break
 
+        if "asym_id" in batch:
+            outputs["asym_id"] = feats["asym_id"]
+
         # Run auxiliary heads
         outputs.update(self.aux_heads(outputs))
 

openfold/model/triangular_multiplicative_update.py

@@ -435,7 +435,7 @@ class TriangleMultiplicativeUpdate(BaseTriangleMultiplicativeUpdate):
         # reduced-precision modes
         a_std = a.std()
         b_std = b.std()
-        if(a_std != 0. and b_std != 0.):
+        if(is_fp16_enabled() and a_std != 0. and b_std != 0.):
             a = a / a.std()
             b = b / b.std()
 
@@ -589,6 +589,9 @@ class FusedTriangleMultiplicativeUpdate(BaseTriangleMultiplicativeUpdate):
 
         # Prevents overflow of torch.matmul in combine projections in
         # reduced-precision modes
+        a_std = a.std()
+        b_std = b.std()
+        if (is_fp16_enabled() and a_std != 0. and b_std != 0.):
             a = a / a.std()
             b = b / b.std()
 

openfold/utils/geometry/vector.py

@@ -193,7 +193,7 @@ def square_euclidean_distance(
     difference = vec1 - vec2
     distance = difference.dot(difference)
     if epsilon:
-        distance = torch.maximum(distance, epsilon)
+        distance = torch.clamp(distance, min=epsilon)
     return distance
 
 

openfold/utils/import_weights.py

@@ -617,7 +617,7 @@ def generate_translation_dict(model, version, is_multimer=False):
 
         translations["evoformer"].update(template_param_dict)
 
-    if "_ptm" in version:
+    if is_multimer or "_ptm" in version:
         translations["predicted_aligned_error_head"] = {
             "logits": LinearParams(model.aux_heads.tm.linear)
         }

openfold/utils/loss.py

@@ -25,6 +25,8 @@ from typing import Dict, Optional, Tuple
 from openfold.np import residue_constants
 from openfold.utils import feats
 from openfold.utils.rigid_utils import Rotation, Rigid
+from openfold.utils.geometry.vector import Vec3Array, euclidean_distance
+from openfold.utils.all_atom_multimer import get_rc_tensor
 from openfold.utils.tensor_utils import (
     tree_map,
     tensor_tree_map,
@@ -87,6 +89,7 @@ def compute_fape(
     target_positions: torch.Tensor,
     positions_mask: torch.Tensor,
     length_scale: float,
+    pair_mask: Optional[torch.Tensor] = None,
     l1_clamp_distance: Optional[float] = None,
     eps=1e-8,
 ) -> torch.Tensor:
@@ -108,6 +111,9 @@ def compute_fape(
                 [*, N_pts] positions mask
             length_scale:
                 Length scale by which the loss is divided
+            pair_mask:
+                [*,  N_frames, N_pts] mask to use for
+                separating intra- from inter-chain losses.
             l1_clamp_distance:
                 Cutoff above which distance errors are disregarded
             eps:
@@ -134,6 +140,15 @@ def compute_fape(
     normed_error = normed_error * frames_mask[..., None]
     normed_error = normed_error * positions_mask[..., None, :]
 
+    if pair_mask is not None:
+        normed_error = normed_error * pair_mask
+        normed_error = torch.sum(normed_error, dim=(-1, -2))
+
+        mask = frames_mask[..., None] * positions_mask[..., None, :] * pair_mask
+        norm_factor = torch.sum(mask, dim=(-2, -1))
+
+        normed_error = normed_error / (eps + norm_factor)
+    else:
         # FP16-friendly averaging. Roughly equivalent to:
         #
         # norm_factor = (
@@ -157,6 +172,7 @@ def backbone_loss(
     backbone_rigid_tensor: torch.Tensor,
     backbone_rigid_mask: torch.Tensor,
     traj: torch.Tensor,
+    pair_mask: Optional[torch.Tensor] = None,
     use_clamped_fape: Optional[torch.Tensor] = None,
     clamp_distance: float = 10.0,
     loss_unit_distance: float = 10.0,
@@ -184,6 +200,7 @@ def backbone_loss(
         pred_aff.get_trans(),
         gt_aff[None].get_trans(),
         backbone_rigid_mask[None],
+        pair_mask=pair_mask,
         l1_clamp_distance=clamp_distance,
         length_scale=loss_unit_distance,
         eps=eps,
@@ -196,6 +213,7 @@ def backbone_loss(
             pred_aff.get_trans(),
             gt_aff[None].get_trans(),
             backbone_rigid_mask[None],
+            pair_mask=pair_mask,
             l1_clamp_distance=None,
             length_scale=loss_unit_distance,
             eps=eps,
@@ -253,6 +271,7 @@ def sidechain_loss(
         sidechain_atom_pos,
         renamed_atom14_gt_positions,
         renamed_atom14_gt_exists,
+        pair_mask=None,
         l1_clamp_distance=clamp_distance,
         length_scale=length_scale,
         eps=eps,
@@ -266,10 +285,29 @@ def fape_loss(
     batch: Dict[str, torch.Tensor],
     config: ml_collections.ConfigDict,
 ) -> torch.Tensor:
+
+    traj = out["sm"]["frames"]
+    asym_id = batch.get("asym_id")
+    if asym_id is not None:
+        intra_chain_mask = (asym_id[..., None] == asym_id[..., None, :]).to(dtype=traj.dtype)
+        intra_chain_bb_loss = backbone_loss(
+            traj=traj,
+            pair_mask=intra_chain_mask,
+            **{**batch, **config.intra_chain_backbone},
+        )
+        interface_bb_loss = backbone_loss(
+            traj=traj,
+            pair_mask=1. - intra_chain_mask,
+            **{**batch, **config.interface_backbone},
+        )
+        weighted_bb_loss = (intra_chain_bb_loss * config.intra_chain_backbone.weight
+                            + interface_bb_loss * config.interface_backbone.weight)
+    else:
         bb_loss = backbone_loss(
-        traj=out["sm"]["frames"],
+            traj=traj,
             **{**batch, **config.backbone},
         )
+        weighted_bb_loss = bb_loss * config.backbone.weight
 
     sc_loss = sidechain_loss(
         out["sm"]["sidechain_frames"],
@@ -277,7 +315,7 @@ def fape_loss(
         **{**batch, **config.sidechain},
     )
 
-    loss = config.backbone.weight * bb_loss + config.sidechain.weight * sc_loss
+    loss = weighted_bb_loss + config.sidechain.weight * sc_loss
     
     # Average over the batch dimension
     loss = torch.mean(loss)
@@ -654,7 +692,7 @@ def compute_tm(
     n = residue_weights.shape[-1]
     pair_mask = residue_weights.new_ones((n, n), dtype=torch.int32)
     if interface:
-        pair_mask *= (asym_id[..., None] != asym_id[..., None, :])
+        pair_mask *= (asym_id[..., None] != asym_id[..., None, :]).to(dtype=pair_mask.dtype)
 
     predicted_tm_term *= pair_mask
 
@@ -891,6 +929,7 @@ def between_residue_clash_loss(
     atom14_atom_exists: torch.Tensor,
     atom14_atom_radius: torch.Tensor,
     residue_index: torch.Tensor,
+    asym_id: Optional[torch.Tensor] = None,
     overlap_tolerance_soft=1.5,
     overlap_tolerance_hard=1.5,
     eps=1e-10,
@@ -966,9 +1005,13 @@ def between_residue_clash_loss(
     )
     n_one_hot = n_one_hot.type(fp_type)
 
-    neighbour_mask = (
-        residue_index[..., :, None, None, None] + 1
-    ) == residue_index[..., None, :, None, None]
+    neighbour_mask = (residue_index[..., :, None] + 1) == residue_index[..., None, :]
+
+    if asym_id is not None:
+        neighbour_mask = neighbour_mask & (asym_id[..., :, None] == asym_id[..., None, :])
+
+    neighbour_mask = neighbour_mask[..., None, None]
+
     c_n_bonds = (
         neighbour_mask
         * c_one_hot[..., None, None, :, None]
@@ -1010,7 +1053,7 @@ def between_residue_clash_loss(
     # Compute the per atom loss sum.
     # shape (N, 14)
     per_atom_loss_sum = torch.sum(dists_to_low_error, dim=(-4, -2)) + torch.sum(
-        dists_to_low_error, axis=(-3, -1)
+        dists_to_low_error, dim=(-3, -1)
     )
 
     # Compute the hard clash mask.
@@ -1019,17 +1062,20 @@ def between_residue_clash_loss(
             dists < (dists_lower_bound - overlap_tolerance_hard)
     )
 
+    per_atom_num_clash = torch.sum(clash_mask, dim=(-4, -2)) + torch.sum(clash_mask, dim=(-3, -1))
+
     # Compute the per atom clash.
     # shape (N, 14)
     per_atom_clash_mask = torch.maximum(
-        torch.amax(clash_mask, axis=(-4, -2)),
-        torch.amax(clash_mask, axis=(-3, -1)),
+        torch.amax(clash_mask, dim=(-4, -2)),
+        torch.amax(clash_mask, dim=(-3, -1)),
     )
 
     return {
         "mean_loss": mean_loss,  # shape ()
         "per_atom_loss_sum": per_atom_loss_sum,  # shape (N, 14)
         "per_atom_clash_mask": per_atom_clash_mask,  # shape (N, 14)
+        "per_atom_num_clash": per_atom_num_clash # shape (N, 14)
     }
 
 
@@ -1109,6 +1155,8 @@ def within_residue_violations(
         (dists < atom14_dists_lower_bound) | (dists > atom14_dists_upper_bound)
     )
 
+    per_atom_num_clash = torch.sum(violations, dim=-2) + torch.sum(violations, dim=-1)
+
     # Compute the per atom violations.
     per_atom_violations = torch.maximum(
         torch.max(violations, dim=-2)[0], torch.max(violations, axis=-1)[0]
@@ -1117,6 +1165,7 @@ def within_residue_violations(
     return {
         "per_atom_loss_sum": per_atom_loss_sum,
         "per_atom_violations": per_atom_violations,
+        "per_atom_num_clash": per_atom_num_clash
     }
 
 
@@ -1146,7 +1195,20 @@ def find_structural_violations(
         residue_constants.van_der_waals_radius[name[0]]
         for name in residue_constants.atom_types
     ]
+
     atomtype_radius = atom14_pred_positions.new_tensor(atomtype_radius)
+
+    #TODO: Consolidate monomer/multimer modes
+    asym_id = batch.get("asym_id")
+    if asym_id is not None:
+        residx_atom14_to_atom37 = get_rc_tensor(
+            residue_constants.RESTYPE_ATOM14_TO_ATOM37, batch["aatype"]
+        )
+        atom14_atom_radius = (
+            batch["atom14_atom_exists"]
+            * atomtype_radius[residx_atom14_to_atom37.long()]
+        )
+    else:
         atom14_atom_radius = (
             batch["atom14_atom_exists"]
             * atomtype_radius[batch["residx_atom14_to_atom37"]]
@@ -1158,6 +1220,7 @@ def find_structural_violations(
         atom14_atom_exists=batch["atom14_atom_exists"],
         atom14_atom_radius=atom14_atom_radius,
         residue_index=batch["residue_index"],
+        asym_id=asym_id,
         overlap_tolerance_soft=clash_overlap_tolerance,
         overlap_tolerance_hard=clash_overlap_tolerance,
     )
@@ -1220,6 +1283,9 @@ def find_structural_violations(
             "clashes_per_atom_clash_mask": between_residue_clashes[
                 "per_atom_clash_mask"
             ],  # (N, 14)
+            "clashes_per_atom_num_clash": between_residue_clashes[
+                "per_atom_num_clash"
+            ],  # (N, 14)
         },
         "within_residues": {
             "per_atom_loss_sum": residue_violations[
@@ -1228,6 +1294,9 @@ def find_structural_violations(
             "per_atom_violations": residue_violations[
                 "per_atom_violations"
             ],  # (N, 14),
+            "per_atom_num_clash": residue_violations[
+                "per_atom_num_clash"
+            ],  # (N, 14)
         },
         "total_per_residue_violations_mask": per_residue_violations_mask,  # (N)
     }
@@ -1349,15 +1418,21 @@ def compute_violation_metrics_np(
 def violation_loss(
     violations: Dict[str, torch.Tensor],
     atom14_atom_exists: torch.Tensor,
+    average_clashes: bool = False,
     eps=1e-6,
     **kwargs,
 ) -> torch.Tensor:
     num_atoms = torch.sum(atom14_atom_exists)
-    l_clash = torch.sum(
-        violations["between_residues"]["clashes_per_atom_loss_sum"]
-        + violations["within_residues"]["per_atom_loss_sum"]
-    )
-    l_clash = l_clash / (eps + num_atoms)
+
+    per_atom_clash = (violations["between_residues"]["clashes_per_atom_loss_sum"] +
+                      violations["within_residues"]["per_atom_loss_sum"])
+
+    if average_clashes:
+        num_clash = (violations["between_residues"]["clashes_per_atom_num_clash"] +
+                     violations["within_residues"]["per_atom_num_clash"])
+        per_atom_clash = per_atom_clash / (num_clash + eps)
+
+    l_clash = torch.sum(per_atom_clash) / (eps + num_atoms)
     loss = (
         violations["between_residues"]["bonds_c_n_loss_mean"]
         + violations["between_residues"]["angles_ca_c_n_loss_mean"]
@@ -1533,6 +1608,64 @@ def masked_msa_loss(logits, true_msa, bert_mask, num_classes, eps=1e-8, **kwargs
     return loss
 
 
+def chain_center_of_mass_loss(
+    all_atom_pred_pos: torch.Tensor,
+    all_atom_positions: torch.Tensor,
+    all_atom_mask: torch.Tensor,
+    asym_id: torch.Tensor,
+    clamp_distance: float = -4.0,
+    weight: float = 0.05,
+    eps: float = 1e-10
+) -> torch.Tensor:
+    """
+    Computes chain centre-of-mass loss. Implements section 2.5, eqn 1 in the Multimer paper.
+
+    Args:
+        all_atom_pred_pos:
+            [*, N_pts, 37, 3] All-atom predicted atom positions
+        all_atom_positions:
+            [*, N_pts, 37, 3] Ground truth all-atom positions
+        all_atom_mask:
+            [*, N_pts, 37] All-atom positions mask
+        asym_id:
+            [*, N_pts] Chain asym IDs
+        clamp_distance:
+            Cutoff above which distance errors are disregarded
+        weight:
+            Weight for loss
+        eps:
+            Small value used to regularize denominators
+    Returns:
+        [*] loss tensor
+    """
+    ca_pos = residue_constants.atom_order["CA"]
+    all_atom_pred_pos = all_atom_pred_pos[..., ca_pos, :]
+    all_atom_positions = all_atom_positions[..., ca_pos, :]
+    all_atom_mask = all_atom_mask[..., ca_pos: (ca_pos + 1)]  # keep dim
+
+    chains, _ = asym_id.unique(return_counts=True)
+    one_hot = torch.nn.functional.one_hot(asym_id, num_classes=chains.shape[0]).to(dtype=all_atom_mask.dtype)
+    one_hot = one_hot * all_atom_mask
+    chain_pos_mask = one_hot.transpose(-2, -1)
+    chain_exists = torch.any(chain_pos_mask, dim=-1).float()
+
+    def get_chain_center_of_mass(pos):
+        center_sum = (chain_pos_mask[..., None] * pos[..., None, :, :]).sum(dim=-2)
+        centers = center_sum / (torch.sum(chain_pos_mask, dim=-1, keepdim=True) + eps)
+        return Vec3Array.from_array(centers)
+
+    pred_centers = get_chain_center_of_mass(all_atom_pred_pos)  # [B, NC, 3]
+    true_centers = get_chain_center_of_mass(all_atom_positions)  # [B, NC, 3]
+
+    pred_dists = euclidean_distance(pred_centers[..., None, :], pred_centers[..., :, None], epsilon=eps)
+    true_dists = euclidean_distance(true_centers[..., None, :], true_centers[..., :, None], epsilon=eps)
+    losses = torch.clamp((weight * (pred_dists - true_dists - clamp_distance)), max=0) ** 2
+    loss_mask = chain_exists[..., :, None] * chain_exists[..., None, :]
+
+    loss = masked_mean(loss_mask, losses, dim=(-1, -2))
+    return loss
+
+
 class AlphaFoldLoss(nn.Module):
     """Aggregation of the various losses described in the supplement"""
     def __init__(self, config):
@@ -1585,7 +1718,7 @@ class AlphaFoldLoss(nn.Module):
             ),
             "violation": lambda: violation_loss(
                 out["violation"],
-                **batch,
+                **{**batch, **self.config.violation},
             ),
         }
 
@@ -1595,6 +1728,12 @@ class AlphaFoldLoss(nn.Module):
                 **{**batch, **out, **self.config.tm},
             )
 
+        if (self.config.chain_center_of_mass.enabled):
+            loss_fns["chain_center_of_mass"] = lambda: chain_center_of_mass_loss(
+                all_atom_pred_pos=out["final_atom_positions"],
+                **{**batch, **self.config.chain_center_of_mass},
+            )
+
         cum_loss = 0.
         losses = {}
         for loss_name, loss_fn in loss_fns.items():

tests/config.py

@@ -6,7 +6,7 @@ consts = mlc.ConfigDict(
         "is_multimer": True,  # monomer: False, multimer: True
         "chunk_size": 4,
         "batch_size": 2,
-        "n_res": 11,
+        "n_res": 22,
         "n_seq": 13,
         "n_templ": 3,
         "n_extra": 17,

tests/data_utils.py

@@ -29,14 +29,16 @@ def random_asym_ids(n_res, split_chains=True, min_chain_len=4):
 
     pieces = []
     asym_ids = []
+    final_idx = n_chain - 1
     for idx in range(n_chain - 1):
         n_stop = (n_res - sum(pieces) - n_chain + idx - min_chain_len)
         if n_stop <= min_chain_len:
+            final_idx = idx
             break
         piece = randint(min_chain_len, n_stop)
         pieces.append(piece)
         asym_ids.extend(piece * [idx])
-    asym_ids.extend((n_res - sum(pieces)) * [n_chain - 1])
+    asym_ids.extend((n_res - sum(pieces)) * [final_idx])
 
     return np.array(asym_ids).astype(np.int64)
 

tests/test_loss.py

@@ -20,6 +20,7 @@ import unittest
 import ml_collections as mlc
 
 from openfold.data import data_transforms
+from openfold.np import residue_constants
 from openfold.utils.rigid_utils import (
     Rotation,
     Rigid,
@@ -42,6 +43,8 @@ from openfold.utils.loss import (
     sidechain_loss,
     tm_loss,
     compute_plddt,
+    compute_tm,
+    chain_center_of_mass_loss
 )
 from openfold.utils.tensor_utils import (
     tree_map,
@@ -233,10 +236,23 @@ class TestLoss(unittest.TestCase):
 
         pred_pos = np.random.rand(n_res, 14, 3).astype(np.float32)
         atom_exists = np.random.randint(0, 2, (n_res, 14)).astype(np.float32)
-        atom_radius = np.random.rand(n_res, 14).astype(np.float32)
         res_ind = np.arange(
             n_res,
         )
+        residx_atom14_to_atom37 = np.random.randint(0, 37, (n_res, 14)).astype(np.int64)
+
+        atomtype_radius = [
+            residue_constants.van_der_waals_radius[name[0]]
+            for name in residue_constants.atom_types
+        ]
+        atomtype_radius = np.array(atomtype_radius).astype(np.float32)
+        atom_radius = (
+                atom_exists
+                * atomtype_radius[residx_atom14_to_atom37]
+        )
+
+        asym_id = None
+        if consts.is_multimer:
             asym_id = random_asym_ids(n_res)
 
         out_gt = f.apply(
@@ -256,6 +272,7 @@ class TestLoss(unittest.TestCase):
             torch.tensor(atom_exists).cuda(),
             torch.tensor(atom_radius).cuda(),
             torch.tensor(res_ind).cuda(),
+            torch.tensor(asym_id).cuda() if asym_id is not None else None,
         )
         out_repro = tensor_tree_map(lambda x: x.cpu(), out_repro)
 
@@ -279,6 +296,36 @@ class TestLoss(unittest.TestCase):
             torch.max(torch.abs(out_gt - out_repro)) < consts.eps
         )
 
+    @compare_utils.skip_unless_alphafold_installed()
+    def test_compute_ptm_compare(self):
+        n_res = consts.n_res
+        max_bin = 31
+        no_bins = 64
+
+        logits = np.random.rand(n_res, n_res, no_bins)
+        boundaries = np.linspace(0, max_bin, num=(no_bins - 1))
+
+        ptm_gt = alphafold.common.confidence.predicted_tm_score(logits, boundaries)
+        ptm_gt = torch.tensor(ptm_gt)
+        logits_t = torch.tensor(logits)
+        ptm_repro = compute_tm(logits_t, no_bins=no_bins, max_bin=max_bin)
+
+        self.assertTrue(
+            torch.max(torch.abs(ptm_gt - ptm_repro)) < consts.eps
+        )
+
+        if consts.is_multimer:
+            asym_id = random_asym_ids(n_res)
+            iptm_gt = alphafold.common.confidence.predicted_tm_score(logits, boundaries,
+                                                                     asym_id=asym_id, interface=True)
+            iptm_gt = torch.tensor(iptm_gt)
+            iptm_repro = compute_tm(logits_t, no_bins=no_bins, max_bin=max_bin,
+                                    asym_id=torch.tensor(asym_id), interface=True)
+
+            self.assertTrue(
+                torch.max(torch.abs(iptm_gt - iptm_repro)) < consts.eps
+            )
+
     def test_find_structural_violations(self):
         n = consts.n_res
 
@@ -335,9 +382,11 @@ class TestLoss(unittest.TestCase):
             "residx_atom14_to_atom37": np.random.randint(
                 0, 37, (n_res, 14)
             ).astype(np.int64),
-            "asym_id": random_asym_ids(n_res)
         }
 
+        if consts.is_multimer:
+            batch["asym_id"] = random_asym_ids(n_res)
+
         pred_pos = np.random.rand(n_res, 14, 3)
 
         config = mlc.ConfigDict(
@@ -632,6 +681,40 @@ class TestLoss(unittest.TestCase):
 
         self.assertTrue(torch.max(torch.abs(out_gt - out_repro)) < consts.eps)
 
+    @compare_utils.skip_unless_alphafold_installed()
+    def test_violation_loss(self):
+        config = compare_utils.get_alphafold_config()
+        c_viol = config.model.heads.structure_module
+        n_res = consts.n_res
+
+        batch = {
+            "seq_mask": np.random.randint(0, 2, (n_res,)).astype(np.float32),
+            "residue_index": np.arange(n_res),
+            "aatype": np.random.randint(0, 21, (n_res,)),
+        }
+
+        if consts.is_multimer:
+            batch["asym_id"] = random_asym_ids(n_res)
+
+        batch = tree_map(lambda n: torch.tensor(n).cuda(), batch, np.ndarray)
+
+        atom14_pred_pos = np.random.rand(n_res, 14, 3).astype(np.float32)
+        atom14_pred_pos = torch.tensor(atom14_pred_pos).cuda()
+
+        batch = data_transforms.make_atom14_masks(batch)
+
+        loss_sum_clash = violation_loss(
+            find_structural_violations(batch, atom14_pred_pos, **c_viol),
+            average_clashes=False, **batch
+        )
+        loss_sum_clash = loss_sum_clash.cpu()
+
+        loss_avg_clash = violation_loss(
+            find_structural_violations(batch, atom14_pred_pos, **c_viol),
+            average_clashes=True, **batch
+        )
+        loss_avg_clash = loss_avg_clash.cpu()
+
     @compare_utils.skip_unless_alphafold_installed()
     def test_violation_loss_compare(self):
         config = compare_utils.get_alphafold_config()
@@ -680,10 +763,12 @@ class TestLoss(unittest.TestCase):
         batch = {
             "seq_mask": np.random.randint(0, 2, (n_res,)).astype(np.float32),
             "residue_index": np.arange(n_res),
-            "aatype": np.random.randint(0, 21, (n_res,)),
-            "asym_id": random_asym_ids(n_res)
+            "aatype": np.random.randint(0, 21, (n_res,))
         }
 
+        if consts.is_multimer:
+            batch["asym_id"] = random_asym_ids(n_res)
+
         atom14_pred_pos = np.random.rand(n_res, 14, 3).astype(np.float32)
 
         alphafold.model.tf.data_transforms.make_atom14_masks(batch)
@@ -801,8 +886,7 @@ class TestLoss(unittest.TestCase):
             "backbone_affine_mask": np.random.randint(0, 2, (n_res,)).astype(
                 np.float32
             ),
-            "use_clamped_fape": np.array(0.0),
-            "asym_id": random_asym_ids(n_res)
+            "use_clamped_fape": np.array(0.0)
         }
 
         value = {
@@ -814,6 +898,9 @@ class TestLoss(unittest.TestCase):
             ),
         }
 
+        if consts.is_multimer:
+            batch["asym_id"] = random_asym_ids(n_res)
+
         out_gt = f.apply({}, None, batch, value)
         out_gt = torch.tensor(np.array(out_gt.block_until_ready()))
 
@@ -826,6 +913,16 @@ class TestLoss(unittest.TestCase):
         )
         batch["backbone_rigid_mask"] = batch["backbone_affine_mask"]
         
+        if consts.is_multimer:
+            intra_chain_mask = (batch["asym_id"][..., None]
+                                == batch["asym_id"][..., None, :]).to(dtype=value["traj"].dtype)
+            intra_chain_out = backbone_loss(traj=value["traj"], pair_mask=intra_chain_mask,
+                                            **{**batch, **c_sm.intra_chain_fape})
+            interface_out = backbone_loss(traj=value["traj"], pair_mask=1. - intra_chain_mask,
+                                          **{**batch, **c_sm.interface_fape})
+            out_repro = intra_chain_out + interface_out
+            out_repro = out_repro.cpu()
+        else:
             out_repro = backbone_loss(traj=value["traj"], **{**batch, **c_sm})
             out_repro = out_repro.cpu()
 
@@ -869,14 +966,14 @@ class TestLoss(unittest.TestCase):
             v["sidechains"] = {}
             v["sidechains"][
                 "frames"
-            ] = alphafold.model.r3.rigids_from_tensor4x4(
+            ] = self.am_rigid.rigids_from_tensor4x4(
                 value["sidechains"]["frames"]
             )
-            v["sidechains"]["atom_pos"] = alphafold.model.r3.vecs_from_tensor(
+            v["sidechains"]["atom_pos"] = self.am_rigid.vecs_from_tensor(
                 value["sidechains"]["atom_pos"]
             )
             v.update(
-                alphafold.model.folding.compute_renamed_ground_truth(
+                self.am_fold.compute_renamed_ground_truth(
                     batch,
                     atom14_pred_positions,
                 )
@@ -907,9 +1004,6 @@ class TestLoss(unittest.TestCase):
             ),
         }
 
-        if consts.is_multimer:
-            batch["asym_id"] = random_asym_ids(n_res)
-
         def _build_extra_feats_np():
             b = tree_map(lambda n: torch.tensor(n), batch, np.ndarray)
             b = data_transforms.make_atom14_masks(b)
@@ -950,7 +1044,7 @@ class TestLoss(unittest.TestCase):
         self.assertTrue(torch.max(torch.abs(out_gt - out_repro)) < consts.eps)
 
     @compare_utils.skip_unless_alphafold_installed()
-    @unittest.skipIf(consts.is_multimer or "ptm" not in consts.model, "Not enabled for non-ptm models.")
+    @unittest.skipIf(not consts.is_multimer and "ptm" not in consts.model, "Not enabled for non-ptm models.")
     def test_tm_loss_compare(self):
         config = compare_utils.get_alphafold_config()
         c_tm = config.model.heads.predicted_aligned_error
@@ -1017,6 +1111,33 @@ class TestLoss(unittest.TestCase):
 
         self.assertTrue(torch.max(torch.abs(out_gt - out_repro)) < consts.eps)
 
+    @compare_utils.skip_unless_alphafold_installed()
+    def test_chain_center_of_mass_loss(self):
+        batch_size = consts.batch_size
+        n_res = consts.n_res
+
+        batch = {
+            "all_atom_positions": np.random.rand(batch_size, n_res, 37, 3).astype(np.float32) * 10.0,
+            "all_atom_mask": np.random.randint(0, 2, (batch_size, n_res, 37)).astype(np.float32),
+            "asym_id": np.stack([random_asym_ids(n_res) for _ in range(batch_size)])
+        }
+
+        config = {
+            "weight": 0.05,
+            "clamp_distance": -4.0,
+        }
+
+        final_atom_positions = torch.rand(batch_size, n_res, 37, 3).cuda()
+
+        to_tensor = lambda t: torch.tensor(t).cuda()
+        batch = tree_map(to_tensor, batch, np.ndarray)
+
+        out_repro = chain_center_of_mass_loss(
+            all_atom_pred_pos=final_atom_positions,
+            **{**batch, **config},
+        )
+        out_repro = out_repro.cpu()
+
 
 if __name__ == "__main__":
     unittest.main()