fix: nomic tensor return (#1683)

* fix nomic tensor return

* add typehint

mteb/models/nomic_models.py

@@ -4,6 +4,7 @@
 from functools import partial
 from typing import Any
 
+import numpy as np
 import torch
 import torch.nn.functional as F
 from sentence_transformers import SentenceTransformer
@@ -43,7 +44,7 @@ def encode(  # type: ignore
         prompt_type: PromptType | None = None,
         batch_size: int = 32,
         **kwargs: Any,
-    ):
+    ) -> np.ndarray:
         input_type = self.get_prompt_name(self.model_prompts, task_name, prompt_type)
 
         # default to search_document if input_type and prompt_name are not provided
@@ -60,8 +61,9 @@ def encode(  # type: ignore
                 emb = torch.tensor(emb)
             emb = F.layer_norm(emb, normalized_shape=(emb.shape[1],))
             emb = F.normalize(emb, p=2, dim=1)
-            if kwargs.get("convert_to_tensor", False):
-                emb = emb.cpu().detach().numpy()
+
+        if isinstance(emb, torch.Tensor):
+            emb = emb.cpu().detach().float().numpy()
 
         return emb