source: trunk/sample/miscellaneous/sample_index.mso @ 832

using "types";

# index-1 formulation

FlowSheet index_prob
        PARAMETERS
                e as negative;

        VARIABLES
                y1 as Real;
                y2 as Real;
                x  as Real;

        EQUATIONS
                diff(y1)*'s' = y2;
                diff(y2)*'s' = x;
                y1 - e*x = sin(time*'rad/s');

        SET
                e = -0.1; # system is unstable if e > 0, and index-3 if e = 0

        INITIAL
#               y1 = 1; # initial condition that tends to be inconsistent when e goes to zero
                y1 = 0;
                y2 = 1;

        OPTIONS
                DAESolver (File = "dasslc");
                TimeStep = 0.1;
                TimeEnd = 10;
                TimeUnit = 's';
end

# index-3 formulation

FlowSheet index_prob2
        VARIABLES
                y1 as Real;
                y2 as Real;
                x  as Real;

        EQUATIONS
                diff(y1)*'s' = y2;
                diff(y2)*'s' = x;
                y1 = sin(time*'rad/s');

        OPTIONS
                DAESolver (File = "dasslc");
                TimeStep = 0.1;
                TimeEnd = 10;
                TimeUnit = 's';
end