zagto commented on code in PR #14223:
URL: https://github.com/apache/arrow/pull/14223#discussion_r1091076673


##########
dev/archery/archery/integration/datagen.py:
##########
@@ -193,6 +193,28 @@ def generate_range(self, size, lower, upper, name=None,
         return PrimitiveColumn(name, size, is_valid, values)
 
 
+# Integer field that fulfils the requirements for the run ends field of RLE.
+# The integers are positive and in a strictly increasing sequence
+class RunEndsField(IntegerField):
+    def __init__(self, name, bit_width, *, nullable=False,
+                 metadata=None):
+        super().__init__(name, is_signed=True, bit_width=bit_width,
+                         nullable=nullable, metadata=metadata, min_value=1)
+
+    def generate_range(self, size, lower, upper, name=None,
+                       include_extremes=False):
+        # values = np.random.randint(lower, upper, size=size, dtype=np.int64)
+        rng = np.random.default_rng()
+        values = rng.choice(2 ** (self.bit_width - 1) - 1, size=size, 
replace=False)

Review Comment:
   ```suggestion
           values = rng.choice(2 ** (self.bit_width - 1) - 1, size=size, 
replace=False)
           values += 1
   ```
   > A run must have have a length of at least 1. This means the values in the
   run ends array all are positive and in strictly ascending order.
   In the spec, we explicitly forbid zero-length runs. I think what is missing 
here is increasing each array value by 1. The range end argument passed to 
rng.choice already contains `- 1`. Since the argument to rng.choice is defined 
as the first value that is not possible, the largest value we generate 
currently is `2 ** (self.bit_width - 1) - 2`, which seems one to low



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]

Reply via email to