File Formats#
Instead of building a model using one of the APIs, all model information can be read from a text file. It is also possible to write model information into a text file. Moreover, other information, such as solution values, attributes, or parameters, can be read and written via text files as well. The Gurobi Optimizer works with a variety of text file formats which are discussed in this section.
Note that all of the Gurobi file I/O routines can work with compressed
versions of these files. Specifically, the Gurobi Optimizer can read or
write files with the following extensions: .zip
, .gz
, .bz2
, .7z
or
.xz
(assuming that the associated compression tool, e.g., 7zip
for
.7z
, is installed on your machine and a corresponding entry is part
of your PATH environment variable).
Model file formats
These text file formats can be used to read or write model information:
File format 
Description 

This is the most widely used format for storing math programming models. It is recommended to use this format (or REW) for optimization. 

This format is identical to the MPS format but with anonymized variable and constraint names. 

This format is identical to the MPS format but it holds the dual formulation of a pure LP model. 

This format is a human readable version of MPS file format. It, however, does not preserve column order when read, and typically does not preserve the exact numerical values of the coefficients. 

This format is identical to the LP format but with anonymized variable and constraint names. 

This format is identical to the LP format but it holds the dual formulation of a pure LP model. 

This format is identical to the LP format but it is used for Irreducible Inconsistent Subsystem (IIS) models. 

This format is used to store pseudoboolean satisfaction and pseudoboolean optimization models. 
Solution file formats
These text file formats can be used to read or write solution information:
File format 
Description 

This format holds solution information, i.e., solution values for all variables. 

This format holds solution information, i.e., solution values for all variables and additional information about the results of the optimization. 

This format holds the solution information necessary for a full MIP start. 

This format holds simplex basis information. Importing this data into a continuous models allows the simplex algorithm to start from the given simplex basis. 
Solution information can only be written after the model has been optimized and a solution is available. On the other hand, all solution file formats can be used to import solution information to start optimization with a known feasible solution. However, preferably an MST file is used when providing MIP start information for a MIP model. It is also possible to hand over partial solution information, i.e., MST or SOL files that contain only a subset of variables with values.
Other File Formats
File format 
Description 

This format is used to hold MIP hints. Importing this data into a MIP model guides the MIP search towards a guess at a highquality feasible solution. 

This format is used to hold MIP variable branching priorities. Importing this data into a MIP model affects the search strategy. 

This format stores a collection of attributes of a model, including (multiple) MIP starts, solution, basis information, partitions, variable hints and branching priorities. 

This format holds parameter values. Importing this data into a model changes the values of the referenced parameters. 