This is the original implementation of lDDT, from 2013.
You should instead be using version 2.0, incorporated into the Structure Assessment tool!
If you use local distance difference test (lDDT), please cite the following reference:
Mariani V, Biasini M, Barbato A, Schwede T
lDDT: a local superposition-free score for comparing protein structures and models using distance difference tests.
Bioinformatics 29, 2722-2728. (2013) 2398656810.1093/bioinformatics/btt473