@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        SimpleMatrix that = (SimpleMatrix) o;

        if (!that.columnNames.keySet().equals(this.columnNames.keySet())) return false;
        if (!that.data.keySet().equals(this.data.keySet())) return false;

        for (String column : this.columnNames.keySet())
            if (!that.getTimeSeries(column).equals(this.getTimeSeries(column)))
                return false;

        return true;
    }