public void findMinimum() {
        this.minimum = null;
        this.minVarIndex = -1;
        this.minInvIndex = -1;
        for(int var=0; var<this.numOfVar; var++) {
            for(int inv=0; inv<this.numOfInv; inv++) {
                Double score = this.getScore(inv,var);
                if (score!=null) {
                    if (minimum==null || score.doubleValue()<minimum.doubleValue()) {
                        this.minimum = score;
                        this.minVarIndex = var;
                        this.minInvIndex = inv;
                    }
                }
            }
        }
    }