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

///
///    This file is part of ILNumerics Community Edition.
///
///    ILNumerics Community Edition - high performance computing for applications.
///    Copyright (C) 2006 - 2012 Haymo Kutschbach, http://ilnumerics.net
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///    it under the terms of the GNU General Public License version 3 as published by
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///    Copyright (c) 2006 - 2009 the Open Toolkit library.
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using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices; 
using ILNumerics.Storage;
using ILNumerics.Misc;
using ILNumerics.Native;
using ILNumerics.Exceptions;

namespace ILNumerics {

    public partial class ILMath {

        /// <summary>
        /// Create double matrix having unity diagonal values  
        /// </summary>
        /// <param name="rows">Number of rows</param>
        /// <param name="columns">Number of columns</param>
        /// <returns>Unity matrix (diagonal matrix) of type double</returns>
        public static ILRetArray<double> eye(int rows, int columns) {
            using (ILScope.Enter()) {
                ILArray<double> ret = zeros(rows, columns);
                int diagLen = Math.Min(rows, columns);
                for (int i = 0; i < diagLen; i++)
                    ret.SetValue(1.0, i, i);
                return ret;
            }
        }
        /// <summary>
        /// Create unity matrix, arbitrary numeric type
        /// </summary>
        /// <param name="rows">Number of rows</param>
        /// <param name="columns">Number of columns</param>
        /// <returns>Unity matrix (diagonal matrix) of element type T</returns>
        /// <typeparam name="T">Element type</typeparam>
        /// <exception cref="ILNumerics.Exceptions.ILArgumentException">If the type specified is not supported. Supported types are: double, float, complex, fcomplex, int, long, short, byte</exception>
        public static ILRetArray<T> eye<T>(int rows, int columns) {
            using (ILScope.Enter()) {
                int diagLen = Math.Min(rows, columns);
                ILArray<T> o = ones<T>(new ILSize(1,diagLen)); 
                if (isnull(o))
                    throw new ILArgumentException("eye does not support elements of type '" + typeof(T).Name + "'"); 
                ILArray<T> ret = zeros<T>(rows, columns);
                for (int i = 0; i < diagLen; i++)
                    ret.SetValue(o.GetValue(i), i, i);
                return ret;
            }
        }

    }
}