source: branches/HeuristicLab.Problems.GaussianProcessTuning/ILNumerics.2.14.4735.573/Functions/builtin/logspace.cs @ 11194

///
///    This file is part of ILNumerics Community Edition.
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///    ILNumerics Community Edition - high performance computing for applications.
///    Copyright (C) 2006 - 2012 Haymo Kutschbach, http://ilnumerics.net
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using System;
using System.Collections.Generic;
using System.Text;
using ILNumerics;
using ILNumerics.Exceptions;
using ILNumerics.Storage;
using ILNumerics.Misc;

namespace ILNumerics {
    public partial class ILMath {
        /// <summary>
        /// Create logarithmically spaced row vector of 30 elements 
        /// </summary>
        /// <param name="start">First exponent value</param>
        /// <param name="end">Last exponent value</param>
        /// <returns>Row vector with 30 elements logathmically spaced between 10^start and 10^end</returns>
        public static ILRetArray<double> logspace (ILInArray<double> start, ILInArray<double> end) {
            return logspace(start, end,30); 
        }

        /// <summary>
        /// Create logarithmically spaced row vector
        /// </summary>
        /// <param name="start">First exponent value</param>
        /// <param name="end">Last exponent value</param>
        /// <param name="length">Number of elements to create</param>
        /// <returns>Row vector with 'length' elements logarithmically spaced between 10^start and 10^end</returns>
        public static ILRetArray<double> logspace (ILInArray<double> start, ILInArray<double> end, ILInArray<double> length) {
            using (ILScope.Enter(start,end, length)) {
                if (end == ILMath.pi)
                    end = Math.Log10(pi); 
                if (length < 2) 
                    return new ILRetArray<double>(new double[1]{Math.Pow(10,(double)end)},1,1); 
                ILArray<double> fact = ( end - start ) / (length - 1); 
                return pow(10.0, linspace<double>(start,end,length));  
            }
        }    
    }
}