///
/// 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
///
/// ILNumerics Community Edition is free software: you can redistribute it and/or modify
/// it under the terms of the GNU General Public License version 3 as published by
/// the Free Software Foundation.
///
/// ILNumerics Community Edition is distributed in the hope that it will be useful,
/// but WITHOUT ANY WARRANTY; without even the implied warranty of
/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
/// GNU General Public License for more details.
///
/// You should have received a copy of the GNU General Public License
/// along with ILNumerics Community Edition. See the file License.txt in the root
/// of your distribution package. If not, see .
///
/// In addition this software uses the following components and/or licenses:
///
/// =================================================================================
/// The Open Toolkit Library License
///
/// Copyright (c) 2006 - 2009 the Open Toolkit library.
///
/// Permission is hereby granted, free of charge, to any person obtaining a copy
/// of this software and associated documentation files (the "Software"), to deal
/// in the Software without restriction, including without limitation the rights to
/// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
/// the Software, and to permit persons to whom the Software is furnished to do
/// so, subject to the following conditions:
///
/// The above copyright notice and this permission notice shall be included in all
/// copies or substantial portions of the Software.
///
/// =================================================================================
///
using System;
using System.Collections.Generic;
using System.Text;
using ILNumerics;
namespace ILNumerics {
///
/// A helper class that can be used to generate various simple yet non-trivial test data sets
///
public class ILSpecialData : ILMath {
///
/// Generate sinc function in 2D, useful for plotting examples
///
/// Number of rows
/// Number of columns
/// Influences the number of periods to be drawn in both directions. 1 will result in 4 zero crossings, higher values result in more, lower values in less zero crossings.
/// Matrix with sinc data in 2 dimensions
public static ILRetArray sinc (int rows, int cols, float periods) {
using (ILScope.Enter()) {
ILArray X = repmat(vec(-cols,2.0,cols-1).T,rows,1) / cols*pi*2*periods;
ILArray Y = repmat(vec(-rows,2.0,rows-1),1,cols) / rows*pi*2*periods;
ILArray ret = sqrt(X * X + Y * Y);
ret[ret == 0.0] = MachineParameterDouble.eps;
ret.a = sin(ret)/ret;
return ret;
}
}
///
/// Generate sinc function in 2D, useful for plotting examples
///
/// Number of rows
/// Number of columns
/// Matrix with sinc data in 2 dimensions
/// The function generates 4 zero crossings in each direction
public static ILRetArray sinc(int rows, int cols) {
return sinc(rows, cols, 1.0f);
}
///
/// Generate sinc function in 2D, single precision, useful for plotting examples
///
/// Number of rows
/// Number of columns
/// Matrix with sinc data in 2 dimensions
/// The function generates 4 zero crossings in each direction
public static ILRetArray sincf(int rows, int cols) {
return tosingle(sinc(rows, cols, 1.0f));
}
///
/// Generate sinc function in 2D, useful for plotting examples
///
/// Number of rows
/// Number of columns
/// Influences the number of periods to be drawn in both directions. 1 will result in 4 zero crossings, higher values result in more, lower values in less zero crossings.
/// Matrix with sinc data in 2 dimensions
public static ILRetArray sincf(int rows, int cols, float periods) {
return tosingle(sinc(rows,cols,periods));
}
///
/// Create specified periods of sine and cosine data
///
/// Number of samples
/// Number of (full) periods to be generated, must be > 0
/// Matrix with sine data in first column, cosine data in second column
public static ILRetArray sincos1D(int numSamples, double periods) {
using (ILScope.Enter()) {
ILArray t = linspace(0.0, 2 * pi * periods, numSamples);
return horzcat(sin(t).T, cos(t).T);
}
}
///
/// Create specified periods of sine and cosine data, single precision
///
/// Number of samples
/// Number of (full) periods to be generated, must be > 0
/// Matrix with sine data in first column, cosine data in second column
public static ILRetArray sincos1Df(int numSamples, double periods) {
using (ILScope.Enter()) {
ILArray t = linspace(0, 2 * pi * periods, numSamples);
return horzcat(sin(t).T, cos(t).T);
}
}
///
/// Create demo data for surface plots looking like a waterfall
///
/// Number of rows
/// Number of columns
/// Matrix with data showing a waterfall terrain.
public static ILRetArray waterfall(int rows, int cols) {
using (ILScope.Enter()) {
ILArray a = rand(rows, cols);
ILArray bord = rand(1, cols) * 3 + (rows / 2);
for (int c = 0; c < cols; c++) {
int b = (int)(bord[c] - sin(c / cols * pi) * cols / 5);
a[vec(0.0, b), c] = a[vec(0.0, b), c] + 2.0;
}
return a;
}
}
///
/// Create demo data for surface plots looking like a waterfall
///
/// Number of rows
/// Number of columns
/// Matrix with data showing a waterfall terrain.
public static ILRetArray waterfallf(int rows, int cols) {
using (ILScope.Enter()) {
ILArray a = rand(rows, cols);
ILArray bord = rand(1, cols) * 3 + (rows / 2);
for (int c = 0; c < cols; c++) {
int b = (int)(bord[c] - sin(c / cols * pi) * cols / 5);
a[vec(0.0, b), c] = a[vec(0.0, b), c] + 2.0;
}
return tosingle(a);
}
}
///
/// Create surface data of a sphere
///
/// Number of facettes per angle
/// [Output] X coords
/// [Output] Y coords
/// [Output] Z coords
public static void sphere(int n, ILOutArray X, ILOutArray Y, ILOutArray Z) {
using (ILScope.Enter()) {
ILArray phi = repmat(linspace(-pi, pi, n).T, 1, n);
ILArray rho = repmat(linspace(0, pi, n), n, 1);
Y.a = sin(phi) * sin(rho);
X.a = cos(phi) * sin(rho);
Z.a = cos(rho);
}
}
///
/// Create surface data for a M�bius strip
///
/// Granularity (number of facettes)
/// Width
/// Radius
/// [Output] X coords
/// [Output] Y coords
/// [Output] Z coords
/// M�bius strip is a surfcae, crated by cutting a regular strip, twisting one end by 180 deg and glueing
/// both ends together again.
public static void moebius(int n, double w, double R, ILOutArray X, ILOutArray Y, ILOutArray Z) {
using (ILScope.Enter()) {
ILArray s = repmat(linspace(-w, w, n), n, 1);
ILArray t = repmat(linspace(0, 2 * pi, n).T, 1, n);
X.a = (R + s * cos(0.5 * t)) * cos(t);
Y.a = (R + s * cos(0.5 * t)) * sin(t);
Z.a = s * sin(0.5 * t);
}
}
}
}