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1 @c Copyright (C) 1996, 1997 John W. Eaton |
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2 @c This is part of the Octave manual. |
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3 @c For copying conditions, see the file gpl.texi. |
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4 |
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5 @node Plotting |
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6 @chapter Plotting |
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7 |
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8 All of Octave's plotting functions use @code{gnuplot} to handle the |
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9 actual graphics. There are two low-level functions, @code{gplot} and |
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10 @code{gsplot}, that behave almost exactly like the corresponding |
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11 @code{gnuplot} functions @code{plot} and @code{splot}. A number of |
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12 other higher level plotting functions, patterned after the graphics |
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13 functions found in @sc{Matlab} version 3.5, are also available. |
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14 These higher level functions are all implemented in terms of the two |
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15 low-level plotting functions. |
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16 |
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17 @menu |
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18 * Two-Dimensional Plotting:: |
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19 * Specialized Two-Dimensional Plots:: |
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20 * Three-Dimensional Plotting:: |
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21 * Plot Annotations:: |
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22 * Multiple Plots on One Page:: |
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23 * Multiple Plot Windows:: |
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24 * Interaction with gnuplot:: |
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25 @end menu |
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26 |
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27 @node Two-Dimensional Plotting |
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28 @section Two-Dimensional Plotting |
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29 |
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30 @deffn {Command} gplot @var{ranges} @var{expression} @var{using} @var{title} @var{style} |
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31 Generate a 2-dimensional plot. |
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32 |
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33 The @var{ranges}, @var{using}, @var{title}, and @var{style} arguments |
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34 are optional, and the @var{using}, @var{title} and @var{style} |
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35 qualifiers may appear in any order after the expression. You may plot |
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36 multiple expressions with a single command by separating them with |
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37 commas. Each expression may have its own set of qualifiers. |
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38 |
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39 The optional item @var{ranges} has the syntax |
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40 |
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41 @example |
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42 [ x_lo : x_up ] [ y_lo : y_up ] |
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43 @end example |
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44 |
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45 @noindent |
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46 and may be used to specify the ranges for the axes of the plot, |
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47 independent of the actual range of the data. The range for the y axis |
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48 and any of the individual limits may be omitted. A range @code{[:]} |
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49 indicates that the default limits should be used. This normally means |
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50 that a range just large enough to include all the data points will be |
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51 used. |
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52 |
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53 The expression to be plotted must not contain any literal matrices |
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54 (e.g. @code{[ 1, 2; 3, 4 ]}) since it is nearly impossible to |
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55 distinguish a plot range from a matrix of data. |
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56 |
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57 See the help for @code{gnuplot} for a description of the syntax for the |
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58 optional items. |
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59 |
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60 By default, the @code{gplot} command plots the second column of a matrix |
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61 versus the first. If the matrix only has one column, it is taken as a |
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62 vector of y-coordinates and the x-coordinate is taken as the element |
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63 index, starting with zero. For example, |
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64 |
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65 @example |
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66 gplot rand (100,1) with linespoints |
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67 @end example |
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68 |
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69 @noindent |
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70 will plot 100 random values and connect them with lines. When |
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71 @code{gplot} is used to plot a column vector, the indices of the |
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72 elements are taken as x values. |
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73 |
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74 If there are more than two columns, you can |
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75 choose which columns to plot with the @var{using} qualifier. For |
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76 example, given the data |
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77 |
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78 @example |
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79 x = (-10:0.1:10)'; |
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80 data = [x, sin(x), cos(x)]; |
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81 @end example |
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82 |
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83 @noindent |
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84 the command |
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85 |
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86 @example |
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87 gplot [-11:11] [-1.1:1.1] \ |
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88 data with lines, data using 1:3 with impulses |
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89 @end example |
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90 |
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91 @noindent |
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92 will plot two lines. The first line is generated by the command |
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93 @code{data with lines}, and is a graph of the sine function over the |
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94 range @minus{}10 to 10. The data is taken from the first two columns of |
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95 the matrix because columns to plot were not specified with the |
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96 @var{using} qualifier. |
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97 |
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98 The clause @code{using 1:3} in the second part of this plot command |
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99 specifies that the first and third columns of the matrix @code{data} |
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100 should be taken as the values to plot. |
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101 |
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102 In this example, the ranges have been explicitly specified to be a bit |
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103 larger than the actual range of the data so that the curves do not touch |
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104 the border of the plot. |
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105 @end deffn |
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106 |
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107 @deffn {Command} gset options |
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108 @deffnx {Command} gshow options |
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109 @deffnx {Command} replot options |
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110 In addition to the basic plotting commands, the whole range of |
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111 @code{gset} and @code{gshow} commands from @code{gnuplot} are available, |
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112 as is @code{replot}. |
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113 |
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114 @findex set |
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115 @findex show |
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116 Note that in Octave 2.0, the @code{set} and @code{show} commands were |
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117 renamed to @code{gset} and @code{gshow} in order to allow for |
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118 compatibility with the @sc{Matlab} graphics and GUI commands in a future |
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119 version of Octave. (For now, the old @code{set} and @code{show} |
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120 commands do work, but they print an annoying warning message to try to |
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121 get people to switch to using @code{gset} and @code{gshow}.) |
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122 |
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123 The @code{gset} and @code{gshow} commands allow you to set and show |
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124 @code{gnuplot} parameters. For more information about the @code{gset} |
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125 and @code{gshow} commands, see the documentation for @code{set} and |
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126 @code{show} in the @code{gnuplot} user's guide (also available on line |
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127 if you run @code{gnuplot} directly, instead of running it from Octave). |
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128 |
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129 The @code{replot} command allows you to force the plot to be |
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130 redisplayed. This is useful if you have changed something about the |
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131 plot, such as the title or axis labels. The @code{replot} command also |
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132 accepts the same arguments as @code{gplot} or @code{gsplot} (except for |
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133 data ranges) so you can add additional lines to existing plots. |
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134 |
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135 For example, |
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136 |
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137 @example |
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138 gset term tek40 |
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139 gset output "/dev/plotter" |
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140 gset title "sine with lines and cosine with impulses" |
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141 replot "sin (x) w l" |
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142 @end example |
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143 |
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144 will change the terminal type for plotting, add a title to the current |
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145 plot, add a graph of |
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146 @iftex |
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147 @tex |
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148 $\sin(x)$ |
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149 @end tex |
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150 @end iftex |
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151 @ifinfo |
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152 sin (x) |
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153 @end ifinfo |
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154 to the plot, and force the new plot to be |
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155 sent to the plot device. This last step is normally required in order |
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156 to update the plot. This default is reasonable for slow terminals or |
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157 hardcopy output devices because even when you are adding additional |
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158 lines with a replot command, gnuplot always redraws the entire plot, and |
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159 you probably don't want to have a completely new plot generated every |
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160 time something as minor as an axis label changes. |
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161 |
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162 @findex shg |
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163 The command @code{shg} is equivalent to executing @code{replot} without |
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164 any arguments. |
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165 @end deffn |
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166 |
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167 @DOCSTRING(automatic_replot) |
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168 |
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169 Note that NaN values in the plot data are automatically omitted, and |
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170 Inf values are converted to a very large value before calling gnuplot. |
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171 |
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172 @c XXX FIXME XXX -- add info about what to do to get plots on remote X |
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173 @c terminals. People often forget how to properly set DISPLAY and run |
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174 @c xhost. |
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175 |
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176 @c XXX FIXME XXX -- add info about getting paper copies of plots. |
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177 |
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178 The @sc{Matlab}-style two-dimensional plotting commands are: |
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179 |
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180 @cindex plotting |
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181 @cindex graphics |
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182 |
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183 @DOCSTRING(plot) |
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184 |
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185 @DOCSTRING(hold) |
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186 |
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187 @DOCSTRING(ishold) |
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188 |
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189 @DOCSTRING(clearplot) |
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190 |
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191 @DOCSTRING(shg) |
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192 |
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193 @DOCSTRING(closeplot) |
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194 |
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195 @DOCSTRING(purge_tmp_files) |
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196 |
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197 @DOCSTRING(axis) |
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198 |
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199 @node Specialized Two-Dimensional Plots |
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200 @section Specialized Two-Dimensional Plots |
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201 |
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202 @DOCSTRING(bar) |
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203 |
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204 @DOCSTRING(contour) |
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205 |
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206 @DOCSTRING(hist) |
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207 |
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208 @DOCSTRING(loglog) |
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209 |
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210 @DOCSTRING(polar) |
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211 |
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212 @DOCSTRING(semilogx) |
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213 |
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214 @DOCSTRING(semilogy) |
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215 |
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216 @DOCSTRING(stairs) |
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217 |
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218 @DOCSTRING(errorbar) |
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219 |
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220 @DOCSTRING(loglogerr) |
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221 |
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222 @DOCSTRING(semilogxerr) |
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223 |
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224 @DOCSTRING(semilogyerr) |
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225 |
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226 @node Three-Dimensional Plotting |
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227 @section Three-Dimensional Plotting |
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228 |
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229 @deffn {Command} gsplot @var{ranges} @var{expression} @var{using} @var{title} @var{style} |
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230 Generate a 3-dimensional plot. |
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231 |
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232 The @var{ranges}, @var{using}, @var{title}, and @var{style} arguments |
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233 are optional, and the @var{using}, @var{title} and @var{style} |
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234 qualifiers may appear in any order after the expression. You may plot |
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235 multiple expressions with a single command by separating them with |
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236 commas. Each expression may have its own set of qualifiers. |
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237 |
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238 The optional item @var{ranges} has the syntax |
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239 |
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240 @example |
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241 [ x_lo : x_up ] [ y_lo : y_up ] [ z_lo : z_up ] |
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242 @end example |
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243 |
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244 @noindent |
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245 and may be used to specify the ranges for the axes of the plot, |
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246 independent of the actual range of the data. The range for the y and z |
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247 axes and any of the individual limits may be omitted. A range |
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248 @code{[:]} indicates that the default limits should be used. This |
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249 normally means that a range just large enough to include all the data |
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250 points will be used. |
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251 |
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252 The expression to be plotted must not contain any literal matrices (e.g. |
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253 @code{[ 1, 2; 3, 4 ]}) since it is nearly impossible to distinguish a |
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254 plot range from a matrix of data. |
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255 |
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256 See the help for @code{gnuplot} for a description of the syntax for the |
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257 optional items. |
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258 |
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259 By default, the @code{gsplot} command plots each column of the |
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260 expression as the z value, using the row index as the x value, and the |
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261 column index as the y value. The indices are counted from zero, not |
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262 one. For example, |
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263 |
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264 @example |
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265 gsplot rand (5, 2) |
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266 @end example |
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267 |
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268 @noindent |
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269 will plot a random surface, with the x and y values taken from the row |
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270 and column indices of the matrix. |
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271 |
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272 If parametric plotting mode is set (using the command |
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273 @kbd{gset parametric}, then @code{gsplot} takes the columns of the |
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274 matrix three at a time as the x, y and z values that define a line in |
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275 three space. Any extra columns are ignored, and the x and y values are |
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276 expected to be sorted. For example, with @code{parametric} set, it |
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277 makes sense to plot a matrix like |
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278 @iftex |
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279 @tex |
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280 $$ |
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281 \left[\matrix{ |
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282 1 & 1 & 3 & 2 & 1 & 6 & 3 & 1 & 9 \cr |
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283 1 & 2 & 2 & 2 & 2 & 5 & 3 & 2 & 8 \cr |
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284 1 & 3 & 1 & 2 & 3 & 4 & 3 & 3 & 7}\right] |
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285 $$ |
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286 @end tex |
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287 @end iftex |
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288 @ifinfo |
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289 |
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290 @example |
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291 1 1 3 2 1 6 3 1 9 |
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292 1 2 2 2 2 5 3 2 8 |
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293 1 3 1 2 3 4 3 3 7 |
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294 @end example |
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295 @end ifinfo |
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296 |
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297 @noindent |
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298 but not @code{rand (5, 30)}. |
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299 @end deffn |
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300 |
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301 The @sc{Matlab}-style three-dimensional plotting commands are: |
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302 |
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303 @DOCSTRING(mesh) |
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304 |
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305 @DOCSTRING(meshgrid) |
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306 |
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307 @DOCSTRING(meshdom) |
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308 |
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309 @node Plot Annotations |
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310 @section Plot Annotations |
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311 |
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312 @DOCSTRING(grid) |
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313 |
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314 @DOCSTRING(title) |
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315 |
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316 @DOCSTRING(bottom_title) |
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317 |
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318 @DOCSTRING(xlabel) |
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319 |
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320 @node Multiple Plots on One Page |
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321 @section Multiple Plots on One Page |
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322 |
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323 The following functions all require a version of @code{gnuplot} that |
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324 supports the multiplot feature. |
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325 |
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326 @DOCSTRING(mplot) |
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327 |
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328 @DOCSTRING(multiplot) |
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329 |
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330 @DOCSTRING(oneplot) |
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331 |
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332 @DOCSTRING(plot_border) |
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333 |
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334 @DOCSTRING(subplot) |
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335 |
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336 @DOCSTRING(subwindow) |
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337 |
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338 @DOCSTRING(top_title) |
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339 |
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340 @node Multiple Plot Windows |
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341 @section Multiple Plot Windows |
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342 |
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343 @DOCSTRING(figure) |
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344 |
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345 @node Interaction with gnuplot |
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346 @section Interaction with @code{gnuplot} |
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347 |
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348 @DOCSTRING(gnuplot_binary) |
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349 |
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350 @DOCSTRING(gnuplot_has_frames) |
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351 |
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352 @DOCSTRING(graw) |
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353 |
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354 @DOCSTRING(gnuplot_command_plot) |
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355 |
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356 @DOCSTRING(gnuplot_command_replot) |
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357 |
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358 @DOCSTRING(gnuplot_command_splot) |
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359 |
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360 @DOCSTRING(gnuplot_command_using) |
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361 |
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362 @DOCSTRING(gnuplot_command_with) |
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363 |
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364 @DOCSTRING(gnuplot_command_axes) |
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365 |
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366 @DOCSTRING(gnuplot_command_title) |
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367 |
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368 @DOCSTRING(gnuplot_command_end) |
