##
#  Copyright: Copyright (c) MOSEK ApS, Denmark. All rights reserved.
#
#  File:      response.R
#
#  Purpose:   This example demonstrates proper response handling
#             for problems solved with the interior-point optimizers.
#
library("Rmosek")

response <- function(filename)
{
    # Read input file 
    r <- mosek_read(filename, list(verbose=1, usesol=FALSE, useparam=TRUE))
    stopifnot(identical(r$response$code, 0))
    prob <- r$prob

    # Ensure that we always have the interior-point solution
    prob$iparam <- list(REQUEST_INTPNT=1)

    # Perform the optimization.
    r <- mosek(prob, list(verbose=10))
    # Use the line below instead to disable log output
    #r <- mosek(prob, list(verbose=0))

    # Expected result: The solution status of the interior-point solution is optimal.

    # Check if there was a fatal error
    if (r$response$code != 0 && startsWith(r$response$msg, "MSK_RES_ERR"))
    {
        print(sprintf("Optimization error: %s (%d),", r$response$msg, r$response$code))
    }
    else
    {
        if (r$sol$itr$solsta == 'OPTIMAL')
        {
            print('An optimal interior-point solution is located:')
            print(r$sol$itr$xx)
        }
        else if (r$sol$itr$solsta == 'DUAL_INFEASIBLE_CER')
        {
            print('Dual infeasibility certificate found.')
        }
        else if (r$sol$itr$solsta == 'PRIMAL_INFEASIBLE_CER')
        {
            print('Primal infeasibility certificate found.')
        }
        else if (r$sol$itr$solsta == 'UNKNOWN')
        { 
            # The solutions status is unknown. The termination code 
            # indicates why the optimizer terminated prematurely. 
            print('The solution status is unknown.')
            print(sprintf('Termination code: %s (%d).', r$response$msg, r$response$code))
        }
        else
        {
            printf('An unexpected solution status is obtained.')
        }
    }
}

# Run only if called directly from the command-line
if( sys.nframe() == 0L )
{
    args <- commandArgs(trailingOnly=TRUE)
    if( !file.exists(args[1]) ) {
        stop("Expected problem file as input argument.")
    }

    response(args[1])
}