source: branches/HeuristicLab.Problems.GaussianProcessTuning/ILNumerics.2.14.4735.573/Functions/builtin/randperm.cs @ 9407

///
///    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.Linq;
using System.Text;
using ILNumerics.Misc; 
using ILNumerics.Exceptions; 

namespace ILNumerics {
    public partial class ILMath {

        /// <summary>
        /// Create a random permutation of integers 
        /// </summary>
        /// <param name="length">Number of unique integers to be created</param>
        /// <returns>Vector of length 'length' and element type double</returns>
        public static ILRetArray<double> randperm(ILBaseArray length) {
            using (ILScope.Enter(length)) {
                if (object.Equals(length, null) || !length.IsScalar ||!length.IsNumeric) {
                    throw new ILArgumentException("the length parameter must be a positive integer");
                }
                int len = (int)toint32(length); 
                ILArray<double> ret = empty();
                sort(rand(1, len), ret, 1, false);
                return ret;
            }
        }
    }
}