Lp sol file generator for debugging mathematical models

create_lp_sol_file.py

"""Creates a file which contains info from lp and sol file.

----------------
Sample sol file:
----------------
# Solution for model Mathematical Model
# Objective value = 140
x1 10
x2 20
x3 30

---------------
Sample lp file:
---------------
\ Model Mathematical Model
\ LP format - for model browsing. Use MPS format to capture full model detail.
Minimize
  x1 + 2 x2 + 3 x3
Subject To
 ct1: x1 + x2 >= 25
 ct2: x1 + x3 >= 25
Bounds
 10 <= x1 <= 50
 20 <= x2 <= 45
 30 <= x3 <= 35
End

--------------------------------------
Output file generated by this program:
--------------------------------------
\ Model Mathematical Model
\ LP format - for model browsing. Use MPS format to capture full model detail.
Minimize
  x1 [10.0] + 2 x2 [20.0] + 3 x3 [30.0]
Subject To
 ct1: x1 [10.0] + x2 [20.0] >= 25
 ct2: x1 [10.0] + x3 [30.0] >= 25
Bounds
 10 <= x1 [10.0] <= 50
 20 <= x2 [20.0] <= 45
 30 <= x3 [30.0] <= 35
End
"""

# ------------------------------------------------------------------------------
#                                CONSTANTS
# ------------------------------------------------------------------------------
# Enter the sol file name here
_SOL_FILE_NAME = "sol_file.sol"

# Enter the first n lines that should not be read
_SKIP_FIRST_N_LINES_IN_SOL_FILE = 2

# Enter the lp file name here
_LP_FILE_NAME = "lp_file.lp"

# Enter the output file name here
_OUTPUT_FILE_NAME = "lp_sol_file.txt"

# Symbols enclosing the solution in the output file
_LEFT_SYMBOL_TO_SOL = "["
_RIGHT_SYMBOL_TO_SOL = "]"


def main():
    """Entry point of the program."""
    print("Running...")
    val_for_var = _create_var_val_dict(_SOL_FILE_NAME,
                                       _SKIP_FIRST_N_LINES_IN_SOL_FILE)
    _create_txt_file_from_lp_sol_info(val_for_var, _OUTPUT_FILE_NAME,
                                      _LP_FILE_NAME)
    print(f"{_OUTPUT_FILE_NAME} is created with lp expressions and values")


def _create_var_val_dict(file_name, skip_first_n_lines):
    """Returns a dictionary with key: variable name, value: value assigned."""
    sol_file_info_List = _get_list_of_info_from_file(file_name,
                                                     skip_first_n_lines)
    val_for_var = {}
    for sol_info in sol_file_info_List:
        var, val = sol_info.split(" ")
        val_for_var[var] = float(val)

    return val_for_var


def _create_txt_file_from_lp_sol_info(val_for_var, txt_file_name, lp_file_name):
    """Creates txt file from lp file."""
    with open(f"{txt_file_name}", 'w') as file:
        lp_file_list = _get_list_of_info_from_file(lp_file_name)

        for lp_info in lp_file_list:
            symbols_list = lp_info.split(" ")
            new_symbols_list = []

            for symbol in symbols_list:
                if symbol in val_for_var:
                    new_symbols_list.append(f"{symbol} {_LEFT_SYMBOL_TO_SOL}"
                                            f"{val_for_var[symbol]}"
                                            f"{_RIGHT_SYMBOL_TO_SOL}")
                else:
                    new_symbols_list.append(f"{symbol}")

            new_symbols_list.append("\n")
            file.write(" ".join(new_symbols_list))


def _get_list_of_info_from_file(file_name, skip_first_n_lines=0):
    """Reads and returns list of information from file."""
    with open(file_name) as f:
        if skip_first_n_lines < 1:
            return f.read().splitlines()
        return f.read().splitlines()[skip_first_n_lines:]


if __name__ == '__main__':
    main()