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