some new features

.venv/lib/python3.12/site-packages/sklearn/utils/_isfinite.pyx

@@ -0,0 +1,50 @@
+# Author: John Kirkham, Meekail Zain, Thomas Fan
+
+from libc.math cimport isnan, isinf
+from cython cimport floating
+
+
+cpdef enum FiniteStatus:
+    all_finite = 0
+    has_nan = 1
+    has_infinite = 2
+
+
+def cy_isfinite(floating[::1] a, bint allow_nan=False):
+    cdef FiniteStatus result
+    with nogil:
+        result = _isfinite(a, allow_nan)
+    return result
+
+
+cdef inline FiniteStatus _isfinite(floating[::1] a, bint allow_nan) noexcept nogil:
+    cdef floating* a_ptr = &a[0]
+    cdef Py_ssize_t length = len(a)
+    if allow_nan:
+        return _isfinite_allow_nan(a_ptr, length)
+    else:
+        return _isfinite_disable_nan(a_ptr, length)
+
+
+cdef inline FiniteStatus _isfinite_allow_nan(floating* a_ptr,
+                                             Py_ssize_t length) noexcept nogil:
+    cdef Py_ssize_t i
+    cdef floating v
+    for i in range(length):
+        v = a_ptr[i]
+        if isinf(v):
+            return FiniteStatus.has_infinite
+    return FiniteStatus.all_finite
+
+
+cdef inline FiniteStatus _isfinite_disable_nan(floating* a_ptr,
+                                               Py_ssize_t length) noexcept nogil:
+    cdef Py_ssize_t i
+    cdef floating v
+    for i in range(length):
+        v = a_ptr[i]
+        if isnan(v):
+            return FiniteStatus.has_nan
+        elif isinf(v):
+            return FiniteStatus.has_infinite
+    return FiniteStatus.all_finite