roll_var move to cdef

Author: auderson

pandas/_libs/window/aggregations.pyx

@@ -362,8 +362,8 @@ def roll_var(const float64_t[:] values, ndarray[int64_t] start,
     """
     cdef:
         float64_t mean_x, ssqdm_x, nobs, compensation_add,
-        float64_t compensation_remove, prev_value
-        int64_t s, e, num_consecutive_same_value
+        float64_t compensation_remove, prev_value = values[start[0]]
+        int64_t s, e, num_consecutive_same_value = 0
         Py_ssize_t i, j, N = len(start)
         ndarray[float64_t] output
         bint is_monotonic_increasing_bounds
@@ -385,9 +385,6 @@ def roll_var(const float64_t[:] values, ndarray[int64_t] start,
             # never removed
             if i == 0 or not is_monotonic_increasing_bounds or s >= end[i - 1]:
 
-                prev_value = values[s]
-                num_consecutive_same_value = 0
-
                 mean_x = ssqdm_x = nobs = compensation_add = compensation_remove = 0
                 for j in range(s, e):
                     add_var(values[j], &nobs, &mean_x, &ssqdm_x, &compensation_add,