add linalg to mlx backend (#19698)

Author: lkarthee

keras/src/backend/mlx/__init__.py

@@ -2,6 +2,7 @@
 
 from keras.src.backend.mlx import core
 from keras.src.backend.mlx import image
+from keras.src.backend.mlx import linalg
 from keras.src.backend.mlx import math
 from keras.src.backend.mlx import nn
 from keras.src.backend.mlx import numpy

keras/src/backend/mlx/linalg.py

@@ -0,0 +1,12 @@
+import mlx.core as mx
+
+from keras.src.backend.common import standardize_dtype
+from keras.src.backend.mlx.core import convert_to_tensor
+
+
+def norm(x, ord=None, axis=None, keepdims=False):
+    dtype = standardize_dtype(x.dtype)
+    if "int" in dtype or dtype == "bool":
+        dtype = dtypes.result_type(x.dtype, "float32")
+    x = convert_to_tensor(x, dtype=dtype)
+    return mx.linalg.norm(x, ord=ord, axis=axis, keepdims=keepdims)

keras/src/ops/linalg_test.py

@@ -444,6 +444,8 @@ def _reconstruct(lu, pivots, m, n):
         )
     )
     def test_norm(self, ndim, ord, axis, keepdims):
+        if backend.backend() == "mlx" and ord == "nuc":
+            self.skipTest("ord='nuc' not supported in MLX")
         if ndim == 1:
             x = np.random.random((5,))
         else: