Add edge weight type CEIL_2D (#130)

Author: leonlan

README.md

@@ -163,7 +163,8 @@ You can set the `compute_distances` argument in `read_instance` to disable this
 Following the VRPLIB conventions, the edge weights are computed based on the `EDGE_WEIGHT_TYPE` specification, and in some cases the `EDGE_WEIGHT_FORMAT` specification. `vrplib` currently supports two categories of edge weight types:
 - `*_2D`: Euclidean distances based on the node coordinates data.
     - `EUC_2D`: Double precision distances without rounding.
-    - `FLOOR_2D`: Round down all distances to down to an integer.
+    - `FLOOR_2D`: Round down all distances to an integer.
+    - `CEIL_2D`: Round up all distances to an integer.
     - `EXACT_2D`: Multiply the distances by 1000, round to the nearest integer.
 - `EXPLICIT`: the distance data is explicitly provided, in partial or full form. The `EDGE_WEIGHT_FORMAT` specification must be present. We support the following two edge weight formats:
   - `LOWER_ROW`: Lower row triangular matrix without diagonal entries.

tests/parse/test_parse_distances.py

@@ -35,7 +35,7 @@ def test_unknown_edge_weight_type_and_format(
 
 
 @pytest.mark.parametrize(
-    "edge_weight_type", ["EUC_2D", "FLOOR_2D", "EXACT_2D"]
+    "edge_weight_type", ["EUC_2D", "FLOOR_2D", "CEIL_2D", "EXACT_2D"]
 )
 def test_raise_no_coordinates_euclidean_distances(edge_weight_type):
     """
@@ -51,6 +51,7 @@ def test_raise_no_coordinates_euclidean_distances(edge_weight_type):
     [
         ("EUC_2D", [[0, np.sqrt(2)], [np.sqrt(2), 0]]),
         ("FLOOR_2D", [[0, 1], [1, 0]]),
+        ("CEIL_2D", [[0, 2], [2, 0]]),
         ("EXACT_2D", [[0, 1414], [1414, 0]]),
     ],
 )

vrplib/parse/parse_distances.py

@@ -56,6 +56,9 @@ def parse_distances(
         if edge_weight_type == "EXACT_2D":
             return np.round(distance * 1000)
 
+        if edge_weight_type == "CEIL_2D":
+            return np.ceil(distance)
+
     if edge_weight_type == "EXPLICIT":
         if edge_weight_format == "LOWER_ROW":
             # TODO Eilon instances edge weight specifications are incorrect in