override dtype with quant (#1062)

llms/mlx_lm/convert.py

@@ -31,7 +31,7 @@ def configure_parser() -> argparse.ArgumentParser:
     )
     parser.add_argument(
         "--dtype",
-        help="Type to save the parameters, ignored if -q is given.",
+        help="Type to save the non-quantized parameters.",
         type=str,
         choices=["float16", "bfloat16", "float32"],
         default="float16",

llms/mlx_lm/models/gemma2.py

@@ -111,7 +111,7 @@ class MLP(nn.Module):
         self.up_proj = nn.Linear(dim, hidden_dim, bias=False)
 
     def __call__(self, x) -> mx.array:
-        return self.down_proj(nn.gelu(self.gate_proj(x)) * self.up_proj(x))
+        return self.down_proj(nn.gelu_approx(self.gate_proj(x)) * self.up_proj(x))
 
 
 class TransformerBlock(nn.Module):

llms/mlx_lm/utils.py

@@ -720,7 +720,7 @@ def convert(
     model, config, tokenizer = fetch_from_hub(model_path, lazy=True)
 
     weights = dict(tree_flatten(model.parameters()))
-    dtype = mx.float16 if quantize else getattr(mx, dtype)
+    dtype = getattr(mx, dtype)
     weights = {k: v.astype(dtype) for k, v in weights.items()}
 
     if quantize and dequantize: