Core plot semi-log graph

-(NSUInteger)numberOfRecordsForPlot:(CPTPlot *)plot {
    return 50;
}

-(NSNumber *)numberForPlot:(CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index {
    double val = index/10.0;
    //NSLog(@"index = %d, val = %f, val^2 = %f", index, val, val*val);
    if (fieldEnum == CPTScatterPlotFieldX) {
        return [NSNumber numberWithDouble:val];
    } else {
        if (plot.identifier == @"X Squared Plot") {
            return [NSNumber numberWithDouble:exp(val)];
        } else {
            return [NSNumber numberWithDouble:val*val];
        }
    }

}
#pragma mark - View lifecycle

-(void)setupGraphWithXRangeLocation:(float)xLocation XLength:(float)xLength YRangeLocation:(float)yLocation YLength:(float)yLength {

    graph = [[CPTXYGraph alloc] initWithFrame:self.view.bounds];

    CPTGraphHostingView *hostingView = (CPTGraphHostingView *)self.view;
    hostingView.hostedGraph = graph;
    graph.paddingLeft = 20.0;
    graph.paddingTop = 20.0;
    graph.paddingRight = 20.0;
    graph.paddingBottom = 20.0;

    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
    plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(xLocation) length:CPTDecimalFromFloat(xLength)];
    plotSpace.yRange = [CPTPlotRange plotRangeWithLocation:CPTDecimalFromFloat(yLocation) length:CPTDecimalFromFloat(yLength)];

    //plotSpace.yScaleType = CPTScaleTypeLinear;

    CPTMutableLineStyle *lineStyle = [CPTMutableLineStyle lineStyle];
    lineStyle.lineColor = [CPTColor blackColor];
    lineStyle.lineWidth = 2.0f;

    CPTXYAxisSet *axisSet = (CPTXYAxisSet *)graph.axisSet;

    CPTXYAxis *xAxis = axisSet.xAxis;
    xAxis.majorIntervalLength = CPTDecimalFromInt(5);
    xAxis.minorTicksPerInterval = 4;
    xAxis.majorTickLineStyle = lineStyle;
    xAxis.minorTickLineStyle = lineStyle;
    xAxis.axisLineStyle = lineStyle;
    xAxis.minorTickLength = 5.0f;
    xAxis.majorTickLength = 7.0f;
    xAxis.axisTitle.offset = 3.0f;

    CPTXYAxis *yAxis = axisSet.yAxis;
    yAxis.majorIntervalLength = CPTDecimalFromInt(5);
    yAxis.minorTicksPerInterval = 4;
    yAxis.majorTickLineStyle = lineStyle;
    yAxis.minorTickLineStyle = lineStyle;
    yAxis.axisLineStyle = lineStyle;
    yAxis.minorTickLength = 5.0f;
    yAxis.majorTickLength = 7.0f;
    yAxis.axisTitle.offset = 3.0f;

    CPTScatterPlot *xSquaredPlot = [[[CPTScatterPlot alloc] init] autorelease];
    xSquaredPlot.identifier = @"X Squared Plot";

    CPTMutableLineStyle *dataLineStyle = [CPTMutableLineStyle lineStyle];
    dataLineStyle.lineColor = [CPTColor redColor];
    dataLineStyle.lineWidth = 1.0f;

    xSquaredPlot.dataLineStyle = dataLineStyle;
    xSquaredPlot.dataSource =  self;
    [graph addPlot:xSquaredPlot];
    CPTScatterPlot *xInversePlot = [[[CPTScatterPlot alloc] init] autorelease];
    xInversePlot.identifier = @"X Inverse Plot";

    CPTMutableLineStyle *dataLineStyle2 = [CPTMutableLineStyle lineStyle];
    dataLineStyle2.lineColor = [CPTColor blueColor];
    dataLineStyle2.lineWidth = 1.0f;

    xInversePlot.dataLineStyle = dataLineStyle2;
    xInversePlot.dataSource = self;
    [graph addPlot:xInversePlot];

    plotSpace.xScaleType = CPTScaleTypeLinear;
    plotSpace.yScaleType = CPTScaleTypeLog;
}

// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad
{
    [super viewDidLoad];

    [self setupGraphWithXRangeLocation:-1
                               XLength:6
                        YRangeLocation:-1
                               YLength:25];

}