EdgeKey - GTSAM Docs

Authors: Frank Dellaert, et al. (see THANKS for the full author list)

See LICENSE for the license information

An EdgeKey is a utility class in GTSAM used to encode a pair of 32-bit unsigned integers into a single 64-bit gtsam.Key. This can be useful for representing edges in a graph or other paired relationships where each element of the pair fits within 32 bits.

%pip install --quiet gtsam-develop

import gtsam
from gtsam import EdgeKey

Initialization¶

An EdgeKey can be created by providing two 32-bit unsigned integers (i and j). It can also be created by decoding an existing gtsam.Key (integer), assuming it was encoded using the EdgeKey format.

# Create EdgeKey from integers i=10, j=20
ekey1 = EdgeKey(10, 20)
print(f"EdgeKey from (10, 20): {ekey1}") # Uses __str__ which calls operator std::string

# Get the underlying integer key
key1 = ekey1.key()

# Reconstruct EdgeKey from the key
ekey2 = EdgeKey(key1)
print(f"EdgeKey from key {key1}: {ekey2}")

EdgeKey from (10, 20): {10, 20}

EdgeKey from key 42949672980: {10, 20}

Properties and Usage¶

You can access the original i and j values and the combined Key.

edge = EdgeKey(123, 456)

print(f"EdgeKey: {edge}")
print(f"  i: {edge.i()}")
print(f"  j: {edge.j()}")
print(f"  Key: {edge.key()}")

EdgeKey: {123, 456}

  i: 123
  j: 456
  Key: 528280977864