What does 'bad' mean?

[AdamBanham]

Dear Sander,

What does the sysout of 'bad' mean in the following snippet in the solver?

https://github.com/promworkbench/BasicStochasticMiner/blob/8d1485cab435ba51753820149d6e6e01a7fc5cca/src/org/processmining/basicstochasticminer/solver/Solver.java#L53-L63

[AdamBanham]

In one execution of the solver, I saw the following in sysout.

!--- starting run 999 ---!
--- starting discovery of weights ---
--- built equations ---
bad
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--- found solution ---
!--- average weight after 1000 runs ---!
~~~ solved variable ~~~
base_t_1 was set to 1.0
~~~ solved variable ~~~
adjust_x_t_1^0.0 was set to 1.0
~~~ solved variable ~~~
base_t_2 was set to 8.499961831395261
~~~ solved variable ~~~
adjust_x_t_2^0.0 was set to 0.9749784490546685
~~~ solved variable ~~~
base_t_3 was set to 6.061515718802166
~~~ solved variable ~~~
adjust_x_t_3^0.0 was set to 0.9775940931599493
~~~ solved variable ~~~
base_t_5 was set to 8.175634150966115
~~~ solved variable ~~~
adjust_x_t_5^1.0 was set to 0.5726823284575581
~~~ solved variable ~~~
base_t_4 was set to 4.479076187389696
~~~ solved variable ~~~
adjust_x_t_4^1.0 was set to 0.6214623434651779

Should I be worried?

[AdamBanham]

Here is the code snippet I am using, in case you want to debug further.

package org.processmining.qut.exogenousaware.ab.jobs;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.processmining.basicstochasticminer.solver.Division;
import org.processmining.basicstochasticminer.solver.Equation;
import org.processmining.basicstochasticminer.solver.Function;
import org.processmining.basicstochasticminer.solver.Product;
import org.processmining.basicstochasticminer.solver.Solver;
import org.processmining.basicstochasticminer.solver.Sum;
import org.processmining.basicstochasticminer.solver.Variable;
import org.processmining.basicstochasticminer.solver.VariablePower;

public class BPM2024B {

    private static int RUNS = 1000;

    /*
     * Main entry point
     */
    public static void main(String[] args) throws Throwable {
        System.out.println("!--- Starting run 1 ---!");
        Tuple<List<Function>, double[]> out = runSolution();
//      testing for determinism
        for(int j = 0; j < RUNS-1; j++) {
            System.out.println(String.format("!--- starting run %d ---!", j+1));
            Tuple<List<Function>, double[]> inner = runSolution();
            for(int i = 0; i < inner.getRight().length; i++) {
                out.getRight()[i] += inner.getRight()[i];
            }
        }
        System.out.println(
                String.format("!--- average weight after %d runs ---!", RUNS)
        );
        for (int i = 0; i < out.getLeft().size(); i++) {
            System.out.println(
                    "~~~ solved variable ~~~\n"+
                    out.getLeft().get(i).toString()+
                    " was set to "+
                    out.getRight()[i] / RUNS
            );
        }
    }

    public static Tuple<List<Function>,double[]> runSolution() {
        System.out.println("--- starting discovery of weights ---");
        Tuple<List<Equation>,List<Function>> out = buildEquations();
        System.out.println("--- built equations ---");
        int[] fixed = new int[out.getRight().size()];
        int[] nonzero = new int[out.getRight().size()];
        double[] inital = new double[out.getRight().size()];
        for(int i = 0; i < out.getRight().size(); i++) {
            fixed[i] = 0;
            inital[i] =  1;         
            nonzero[i] = 1;
        }
        double[] solvedvalues = Solver.solve(out.getLeft(), out.getRight().size(), fixed, nonzero, inital);
        System.out.println("--- found solution ---");
        return new Tuple<>(out.getRight(), solvedvalues);       
    }

    public static class VariableCounter {

        int count = 0;

        public VariableCounter() {
        }

        public int get() {
            return this.count;
        }

        public void incr() {
            this.count++;
        }
    }

    public static String BASE_T1 = "base_t_1";
    public static String BASE_T2 = "base_t_2";
    public static String BASE_T3 = "base_t_3";
    public static String BASE_T4 = "base_t_4";
    public static String BASE_T5 = "base_t_5";

    public static String ADJUST_X_T1 = "adjust_x_t_1";
    public static String ADJUST_X_T2 = "adjust_x_t_2";
    public static String ADJUST_X_T3 = "adjust_x_t_3";
    public static String ADJUST_X_T4 = "adjust_x_t_4";
    public static String ADJUST_X_T5 = "adjust_x_t_5";

    /*
     * Builds the dummy equations in paper
     */
    public static Tuple<List<Equation>,List<Function>> buildEquations() {
        List<Equation> eqs = new ArrayList<>();
        List<Function> vars = new ArrayList<>();
        Map<String, Tuple<Function,Integer>> varnames = new HashMap<>();
        VariableCounter counter =  new VariableCounter();
//      first equation
//      1/1 = (base_t_1 . adjust_t_1^0)/ (base_t_1 . adjust_t_1^0)
        eqs.add(
                createEquation(1/1.0f, 0, BASE_T1, ADJUST_X_T1, varnames, vars, counter)
        );
//      1/1 = (base_t_1 . adjust_t_1^19)/ (base_t_1 . adjust_t_1^19)
        eqs.add(
                createEquation(1/1.0f, 19, BASE_T1, ADJUST_X_T1, varnames, vars, counter)
        );
//      1/1 = (base_t_1 . adjust_t_1^63)/ (base_t_1 . adjust_t_1^63)
        eqs.add(
                createEquation(1/1.0f, 63, BASE_T1, ADJUST_X_T1, varnames, vars, counter)
        );
//      1/2 = (base_t_2 . adjust_t_2^0) / ( base_t_2 . adjust_t_2^0 + base_t_3 . adjust_t_3^0)
        eqs.add( 
                createEquation(1/2.0f, 0,
                        BASE_T2, ADJUST_X_T2, varnames, vars, counter,
                        new Tuple<>(BASE_T3,ADJUST_X_T3))
        );
//      1/2 = (base_t_3 . adjust_t_3^0) / ( base_t_2 . adjust_t_2^0 + base_t_3 . adjust_t_3^0)
        eqs.add( 
                createEquation(1/2.0f, 0,
                        BASE_T3, ADJUST_X_T3, varnames, vars, counter,
                        new Tuple<>(BASE_T2,ADJUST_X_T2))
        );
//      1/1 = (base_t_2 . adjust_t_2^5) / ( base_t_2 . adjust_t_2^5 + base_t_3 . adjust_t_3^5)
        eqs.add( 
                createEquation(1/1.0f, 5,
                        BASE_T2, ADJUST_X_T2, varnames, vars, counter,
                        new Tuple<>(BASE_T3,ADJUST_X_T3))
        );
//      1/1 = (base_t_2 . adjust_t_2^21) / ( base_t_2 . adjust_t_2^21 + base_t_3 . adjust_t_3^21)
        eqs.add( 
                createEquation(1/1.0f, 21,
                        BASE_T2, ADJUST_X_T2, varnames, vars, counter,
                        new Tuple<>(BASE_T3,ADJUST_X_T3))
        );
//      1/1 = (base_t_3 . adjust_t_3^22) / ( base_t_2 . adjust_t_2^22 + base_t_3 . adjust_t_3^22)
        eqs.add( 
                createEquation(1/1.0f, 22,
                        BASE_T3, ADJUST_X_T3, varnames, vars, counter,
                        new Tuple<>(BASE_T2,ADJUST_X_T2))
        );
//      1/1 = (base_t_3 . adjust_t_3^36) / ( base_t_2 . adjust_t_2^36 + base_t_3 . adjust_t_3^36)
        eqs.add( 
                createEquation(1/1.0f, 36,
                        BASE_T3, ADJUST_X_T3, varnames, vars, counter,
                        new Tuple<>(BASE_T2,ADJUST_X_T2))
        );
//      1/1 = (base_t_2 . adjust_t_2^48) / ( base_t_2 . adjust_t_2^48 + base_t_3 . adjust_t_3^48)
        eqs.add( 
                createEquation(1/1.0f, 48,
                        BASE_T2, ADJUST_X_T2, varnames, vars, counter,
                        new Tuple<>(BASE_T3,ADJUST_X_T3))
        );
//      1/1 = (base_t5 . adjust_t_5^1) / (base_t4 . adjust_t_4^1 + base_t5 . adjust_t_5^1)
        eqs.add( 
                createEquation(1/1.0f, 1,
                        BASE_T5, ADJUST_X_T5, varnames, vars, counter,
                        new Tuple<>(BASE_T4, ADJUST_X_T4)
                )
        );
//      1/1 = (base_t5 . adjust_t_5^9) / (base_t4 . adjust_t_4^9 + base_t5 . adjust_t_5^9)
        eqs.add( 
                createEquation(1/1.0f, 9,
                        BASE_T5, ADJUST_X_T5, varnames, vars, counter,
                        new Tuple<>(BASE_T4, ADJUST_X_T4)
                )
        );
//      ? = 1
//      4/4 = (base_t4 . adjust_t_4^0) / (base_t4 . adjust_t_4^0 + base_t5 . adjust_t_5^0)
//      eqs.add( 
//              createEquation(4/4.0f, 1,
//                      BASE_T4, ADJUST_X_T4, varnames, vars, counter,
//                      new Tuple<>(BASE_T5, ADJUST_X_T5)
//              )
//      );
//      !- ? = next theta -!
//      1/1 = (base_t4 . adjust_t_4^5) / (base_t_4 . adjust_t_4^5) + base_t_5 . adjust_t_5^5)
        eqs.add(
                createEquation(1/1.0f, 5,
                        BASE_T4, ADJUST_X_T4, varnames, vars, counter,
                        new Tuple<>(BASE_T5, ADJUST_X_T5)
                )
        );
//      1/1 = (base_t_4 . adjust_t_4^0) / (base_t_4 . adjust_t_4^0) + base_t_5 . adjust_t_5^0)
        eqs.add(
                createEquation(1/1.0f, 0,
                        BASE_T4, ADJUST_X_T4, varnames, vars, counter,
                        new Tuple<>(BASE_T5, ADJUST_X_T5)
                )
        );
//      1/1 = (base_t_4 . adjust_t_4^36) / (base_t_4 . adjust_t_4^36) + base_t_5 . adjust_t_5^36)
        eqs.add(
                createEquation(1/1.0f, 36,
                        BASE_T4, ADJUST_X_T4, varnames, vars, counter,
                        new Tuple<>(BASE_T5, ADJUST_X_T5)
                )
        );
//      1/1 = (base_t_4 . adjust_t_4^22) / (base_t_4 . adjust_t_4^22) + base_t_5 . adjust_t_5^22)
        eqs.add(
                createEquation(1/1.0f, 22,
                        BASE_T4, ADJUST_X_T4, varnames, vars, counter,
                        new Tuple<>(BASE_T5, ADJUST_X_T5)
                )
        );
//      !- ! = average seen -!
//      1\1 = (base_t_5 . adjust_t_5^5 / (base_t_4 . adjust_t_4^5 + base_t_5 . adjust_t_5^5)
        eqs.add( 
                createEquation(1/1.0f, 5,
                        BASE_T5, ADJUST_X_T5, varnames, vars, counter,
                        new Tuple<>(BASE_T4, ADJUST_X_T4)
                )
        );
        return new Tuple<List<Equation>, List<Function>>(eqs,vars);
    }

    @SafeVarargs
    public static Equation createEquation(
            double value, int power, 
            String topBase, String topAdjust,
            Map<String, Tuple<Function,Integer>> lookup, 
            List<Function> storage, 
            VariableCounter counter,
            Tuple<String,String>... Bottoms) {

//      build top (always the same)
        Function b1 = createVarIfNeeded(topBase, lookup, storage, counter);
        Function x1 = createVarIfNeeded(topAdjust, lookup, storage, counter, power);
        Product top = new Product(b1 , x1);
//      build bottom (different)
        Sum bottom = new Sum(top);
        for (int i = 0; i < Bottoms.length; i++) {
            String botBase = Bottoms[i].getLeft();
            String botAdjust = Bottoms[i].getRight();
            bottom = new Sum(bottom,
                new Product( 
                        createVarIfNeeded(botBase, lookup, storage, counter),
                        createVarIfNeeded(botAdjust, lookup, storage, counter, power)
                )
            );
        }
        Division right = new Division(top, bottom);
//      set value for right
        return new Equation(value, right, 1);
    }

    public static Function createVarIfNeeded(String name, Map<String, Tuple<Function,Integer>> lookup, List<Function> storage, VariableCounter var_count){
        return createVarIfNeeded(name, lookup, storage, var_count, 1);
    }

    public static Function createVarIfNeeded(String name, Map<String, Tuple<Function,Integer>> lookup, List<Function> storage, VariableCounter var_count, int power) {
        Function out;

        if (lookup.containsKey(name)) {
            if (name.contains("adjust")) {
                Tuple<Function,Integer> old = lookup.get(name);
                out = new VariablePower(old.getRight(), name, power);
            } else {
                out = lookup.get(name).getLeft();
            }
        } else {
            if (name.contains("adjust")) {
                out = new VariablePower(var_count.get(),name, power);
                lookup.put(name, new Tuple<>(out, var_count.get()));
            } else {
                out = new Variable(var_count.get(), name);
                lookup.put(name, new Tuple<>(out, var_count.get()));
            }
            storage.add(out);
            var_count.incr();
        }

        return out;
    }

}