Project Input File Specifications

We refer to an optimization job (of one or more instances) as a project. A project input file consists of a set of input data bundled into a single not password protected ZIP archive.

Here is a graphical representation of the structure of a typical project input file:

input/ └── instance1/ │ ├── Param.txt │ ├── Demand.txt │ ├── Exp_mat.txt │ └── Cov_mat.txt └── instance2/ │ ├── Param.txt │ ├── Demand.txt │ ├── Exp_mat.txt │ └── Cov_mat.txt ├── ... └── instancen/ ├── Param.txt ├── Demand.txt ├── Exp_mat.txt └── Cov_mat.txt

Each instance folder instancei, itself under a common root folder input, holds the data files pertaining to this instance. Instance folder names must start with an alphanumeric character without diacritics; for the remaining characters, only alphanumeric characters without diacritics, underscores ('_'), hyphens ('-') and dots ('.') are accepted. Spaces are specifically prohibited.

File/folder names are case sensitive.

Files/folders other than those mentioned above are strictly prohibited.

Special file types such as Unix/NTFS symbolic links and Windows shortcuts are not supported and will mistakenly be considered as text files whose content will probably not match given specifications.

The content of each of the four files for a given instance is described as follows:

  1. Param.txt: This is a parameter file that includes the following information:

    • the real number alpha in ]0,1[ to generate a convex combination of expected travel time and the variance of travel time,
    • the type of the instance; "A" for the adjacent case and "G" for the general case.

    Example:

    alpha 0.1 type A

  2. Demand.txt:  This is a file with n+2 rows, where the first row is the vehicle capacity (a positive integer), while rows 2 to n+2 is the list of customers with their demands (all positive integers). In fact, row 2 represents the depot with demand 0. Note that the first entry of row j = 2 to n+2 must be j-1 (for example, the first entry of row 2 must be 1).

    Example with 3 customers and vehicle capacity 200:

    200 1 0 2 10 3 30 4 10

  3. Exp_Mat.txt: This file is a  ((n+1) * (n+1)) matrix with rows [0 ,1 , ..., n] and columns [0 ,1 , ..., n], where element of row i and column j represents the expected travel time between customers i and j (a positive integer, except on the main diagonal where it must be 0). Note that row 0 and column 0 correspond to the depot.

    Example with n = 3 customers:

       
    0 22 12 18 * 0 * * * * 0 * * * * 0

    where the * should be replaced by positive integers.

  4. Cov_Mat.txt: This file is a (m*m) covariance matrix, where m=(n*(n-1))+(2*n) is the number of arcs. Arcs have the following forms:

    (0,1) , (0,2) , ..., (0,n),  (1,2) , (1,3) , ..., (1,n), (2,1) , (2,3) , ..., (2,n), ... ... ... (n,1) , (n,2) , ..., (n,n-1), (1,n+1), (2,n+1), ..., (n,n+1)

    where 0 and n+1 represent the depot and 1,2, ..., n represent the customers. This matrix must be symmetric and positive semidefinite.

    For example, an instance with 3 customers has 12 arcs (m=3*(3-1)+2*3=12). Therefore, we have a 12*12 covariance matrix whose rows (1 to 12) and columns (1 to 12) correspond to (0,1), (0,2), (0,3), (1,2), (1,3), (2,1), (2,3), (3,1), (3,2), (1,4), (2,4), (3,4).

    2.1 0.02 0.1 -0.05 0.1 0 0.11 0 -0.06 0 0.02 0.30   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *   * * * * * * * * * * * *  

    where the * should be replaced by real numbers.

    5. Project input file example:

    A small example of a ZIP project input file described above

    Actual files referenced in the paper

    Corresponding output files for the 4 input files above

    Note that these results have been obtained on a slightly faster computer than the one used in the paper.