ILNumerics using subarrays and matfiles with structs

Question

First question: Can ILNumerics read matfiles with struct? I couldnt make it work.

I then split the file in matlab and I would like to use it for calculations. but i have problems with the subarray function. I would like to do this:

            using (ILMatFile matRead = new ILMatFile(@"C:\Temp\Dates.mat"))
        {
            ILArray<double> Dates = matRead.GetArray<double>("Dates");
            double x = 736055-1;
            double y = 736237+1;
            ILArray<ILLogical> LogDates = (Dates > x && Dates < y);

        }
        using (ILMatFile matRead = new ILMatFile(@"C:\Temp\Power.mat"))
        {
            ILArray<double> power = matRead.GetArray<double>("Power");
            ILArray<double> tpower = power[LogDates, full];
            double avgpower = tpower.Average();
            Console.WriteLine(avgpower.ToString());
            Console.ReadKey();
        }

This doesnt work for a number of reasons. The logical doesnt take my syntax and I dont really get why. But also the subarry in the second block doesnt work, it doesnt know the full keyword (even though the documentation says it shouldand also it doesnt like the logical. obviously I want to average tpower over all columns and only those rows where the logical condition is one.

thanks. nik

Answer 1

ILLogical is an array itself. You use it like that:

ILLogical LogDates = ILMath.and(Dates > x, Dates < y);

If you still experiencing problems with the subarray, try:

ILArray<double> tpower = power[ILMath.find(LogDates), ILMath.full];

Only, if your class is derived from ILMath, you can ommit the ILMath. identifier! Otherwise, string subarray definitions are sometimes shorter:

ILArray<double> tpower = power[ILMath.find(LogDates), ":"] 

In order to take the average over selected rows, reducing to one:

double avgpower = tpower.Average();  // Linq version
double avgpower = (double)ILMath.sumall(tpower) / tpower.S.NumberOfElements;  // prob. faster on large data