[OpenVINO backend] Support beta operation (#22285)

* Feat: Implements `random.beta` of openvino backend

* Feat: Implements `random.beta` of openvino backend

* Apply pre-commit

* Apply Review

Author: daehyun99

keras/src/backend/openvino/excluded_concrete_tests.txt

@@ -361,9 +361,6 @@ QuantizersTest::test_compute_float8_scale
 QuantizersTest::test_grouped_quantize_with_padding
 QuantizersTest::test_grouped_vs_perchannel_accuracy
 RandomBehaviorTest::test_beta_tf_data_compatibility
-RandomCorrectnessTest::test_beta0
-RandomCorrectnessTest::test_beta1
-RandomCorrectnessTest::test_beta2
 RandomCorrectnessTest::test_truncated_normal0
 RandomCorrectnessTest::test_truncated_normal1
 RandomCorrectnessTest::test_truncated_normal2
@@ -375,10 +372,6 @@ RandomCorrectnessTest::test_uniform1
 RandomCorrectnessTest::test_uniform2
 RandomCorrectnessTest::test_uniform3
 RandomCorrectnessTest::test_uniform4
-RandomDTypeTest::test_beta_bfloat16
-RandomDTypeTest::test_beta_float16
-RandomDTypeTest::test_beta_float32
-RandomDTypeTest::test_beta_float64
 RandomDTypeTest::test_normal_bfloat16
 RandomDTypeTest::test_truncated_normal_bfloat16
 RandomDTypeTest::test_uniform_bfloat16

keras/src/backend/openvino/random.py

@@ -443,4 +443,15 @@ def binomial(shape, counts, probabilities, dtype=None, seed=None):
 
 
 def beta(shape, alpha, beta, dtype=None, seed=None):
-    raise NotImplementedError("`beta` is not supported with openvino backend")
+    seed1 = seed
+    seed2 = seed
+    if isinstance(seed, int):
+        seed2 += 123
+
+    gamma_a = get_ov_output(gamma(shape, alpha, dtype=dtype, seed=seed1))
+    gamma_b = get_ov_output(gamma(shape, beta, dtype=dtype, seed=seed2))
+
+    sum_ab = ov_opset.add(gamma_a, gamma_b).output(0)
+    z = ov_opset.divide(gamma_a, sum_ab).output(0)
+
+    return OpenVINOKerasTensor(z)