Case in point.java

public Tableau makeArtificial() {
    Matrix tmp = getA().mergeRight(Matrix.identity(constraints)).mergeRight(getRHS()); 	//insert identity
    tmp = tmp.mergeDown(new Matrix(1,vars).extend(0,constraints,1d).extend(0,1)); 		//add new cost row
    return new Tableau(tmp);
}

vs

public Tableau makeArtificial() {
    Double[][] tmp = new Double[height][width+height-1];
    int tmpwidth = width+height-1;
    int tmpcost = costRow;
    int tmpbCol = tmpwidth - 1;

    for(int i = 0; i < constraints; i++) { //rows but cost row
        for (int j = 0; j < vars; j++) { //original cols
            tmp[i][j] = matrix[i][j];
        }
        for (int j = 0; j < constraints; j++) { //artificial cols
            tmp[i][vars+j] = (i == j) ? 1d : 0d;
        }
    }
    for (int i = 0; i < constraints; i++) { //bCol
        tmp[i][tmpbCol] = matrix[i][bCol];
    }
    for(int j = 0; j < vars+constraints; j++) { //cost row
        tmp[tmpcost][j] = (j < vars) ? 0d : 1d;
    }
    tmp[tmpcost][tmpbCol] = 0d; //-z
		
    return new Tableau(tmp);
}