Problem pre-check

[Mast86]

checks (some of these may be already built-in in cvxpy):

• there must be objective function and at least one constraint
• all expressions (of and constraints) must be dimensionally consistent
• linearity check
• all items apprearing in equations must be in variables (but this should be alredy checked in generating expressions)
• if two endogenous variables are generated from the same table, they must be connected by an expression (they are disconnected cvxpy variables otherwise).

[Mast86]

when Model instance is generated from existing files, check whether structures of sets, variables provided by yml files are consistent with data gathered from existing sets file, input files and sqlite database.

[Mast86]

in definition of variables from tables (structure_variables.yml file), all sets defining dimensions of the variable must be in the table coordinates list.

[CamiCit]

When uploading data written by the user in sets.xlsx, remove any blank space at the end of a text string (as it could generate errors when aggregating sets or when manipulating input_data.xlsx)