specify or read the range of the values, ....

 specify or read the max min... useful if you want to make 2 graph
based on the same values, otherwise they would be inconsistent between
them, for example graph of download has max 20 min 10 , and graph of
updates has max 5 and min 0, without that the 20 and the 5 would be in
the same place

        MPGraphValuesRange downloadRange=[MPPlot rangeForValues:values];
        MPGraphValuesRange updateRange=[MPPlot rangeForValues:upValues];

        MPGraphValuesRange range=MPGetBiggestRange(downloadRange,
updateRange);

        graph.valueRanges=range;
        updateGraph.valueRanges=range;