I'm using numericY axis and my MaxValue of the axis is dependency property - so it's not pre-defined. My Min value is always 0.  The numericY axis is logarithmic.

I wanna render Y axis tickmarks with the same distance between tickmarks labels, like in non logarithmic axis. Here is the code that calculates the array  of points to render:

public class CustomTickmarkValues : TickmarkValues
    {
        private double _min;
        private double _max;
        public override void Initialize(TickmarkValuesInitializationParameters initializationParameters)
        {
            base.Initialize(initializationParameters);
            _min = 0;
            _max = initializationParameters.VisibleMaximum;
        }

        public override IEnumerable<double> MajorValues()
        {
            var a = Math.Log10(_max)/8;
            var collection = new List<double>();
            collection.Add(_min);
            for (int i = 1; i<= 8; i++)
            {
                collection.Add((int)Math.Pow(10, i * a));
            }

            collection.Add(_max);
            return collection;
        }

        public override IEnumerable<double> MinorValues()
        {
            return new List<double>();
        }
    }

This code generates for me 8 values, then i add max and min values - so it should be 10, but as you can see sometimes its not 10: