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1.1     ! bowersj2    1: \label{Authoring_Dynamic_Plot}
        !             2: Dynamically generated plots are used to produce graphs which will be
        !             3: different for each student who views them. The plots are produced by
        !             4: calling 'gnuplot', and in fact the xml tag for the plots is <gnuplot>.
        !             5: 
        !             6: Dynamically generated plots should be used in conjunction with a perl
        !             7: script block which generates the data to be plotted. If you are using
        !             8: static data a dynamically generated plot is not appropriate because of
        !             9: the overhead associated with generating the plot. In that case, use a
        !            10: picture (see \ref{Authoring_Adding_Pictures}).
        !            11: 
        !            12: There are a great deal of parameters that can be set for a plot. These
        !            13: parameters are accessed by including various sub-tags. By default only
        !            14: the <gnuplot > tag and <curve > tag are present in a plot. The
        !            15: sub-tags allow you to define the axes of the plot, the presence of a
        !            16: key, the placement of gridlines, and the title and legends on the
        !            17: plot. The example given below shows the use of the <axis > sub-tag to
        !            18: set the domain and range shown in the graph. 
        !            19: 
        !            20: Below is an example which produces a simple plot. To use it, create a
        !            21: new problem and \textbf{Edit XML}. Remove all of the text and replace 
        !            22: it with the text below: 
        !            23: 
        !            24: \begin{verbatim}
        !            25: 
        !            26:  <problem >
        !            27:  <script type="loncapa/perl" >
        !            28:  $amplitude = &random(3,5,1);
        !            29:  for ($x=-6.0; $x<=6.0; $x+=0.05) {
        !            30:      push @X,$x;
        !            31:      push @Y, $amplitude * sin($x);
        !            32:  }
        !            33:  </script >
        !            34:  <gnuplot font="medium" width="400" grid="on" 
        !            35:       height="300" border="on" fgcolor="x000000" 
        !            36:       alttag="dynamically generated plot" align="center"  
        !            37:       bgcolor="xffffff" transparent="off" >
        !            38:      <axis ymin="-6.0" ymax="6.0" xmin="-5.0" 
        !            39:            xmax="5.0" color="x000000" /> 
        !            40:      <curve 
        !            41:           linestyle="lines"
        !            42:           pointtype="1"
        !            43:           pointsize="1"
        !            44:           name=""
        !            45:           color="x000000" >
        !            46:          <data >@X</data >
        !            47:          <data >@Y</data >
        !            48:      </curve >
        !            49:  </gnuplot >
        !            50:  <startouttext /><br />
        !            51:  What is the amplitude of this function?
        !            52:  <endouttext />
        !            53:  <numericalresponse answer="$amplitude" >
        !            54:  <responseparam type="tolerance" default="5%" name="tol" 
        !            55:       description="Numerical Tolerance" />
        !            56:  <responseparam name="sig" type="int_range,0-16" default="0,15"  
        !            57:       description="Significant Figures" />
        !            58:  </numericalresponse >
        !            59:  </problem >
        !            60: 
        !            61: \end{verbatim}
        !            62: 
        !            63: Below is a screenshot (in construction space) of the resulting plot.
        !            64: 
        !            65: \includegraphic{dynamic_plot}
        !            66: 
        !            67: It's likely that the above plot doesn't quite look right. It would be
        !            68: nice to have the gridlines drawn every 1 unit instead of every 2
        !            69: units. A title, and labels on the axes, would be a nice
        !            70: addition. Although it's overkill for this example, we can also add a
        !            71: key for the plot. We can accomplish these changes by inserting
        !            72: sub-tags into the <gnuplot > tag. 
        !            73: 
        !            74: Gridlines can be set using the <xtics > and <ytics > tags. The names
        !            75: of these tags correspond to the names of the commands used in
        !            76: gnuplot. We specify the beginning, end, and increment of the tick
        !            77: marks. Gnuplot only puts gridlines on the tick marks. 
        !            78: 
        !            79: Inserting the <title >, <xlabel >, and <ylabel > commands allows us to
        !            80: set the title and axes labels as one would expect. Inserting a <key >
        !            81: tag, but not changing any of the information in it, signals gnuplot to
        !            82: place a key in the graph. If we decide we don't want the key, deleting
        !            83: the <key > tag will remove it from the graph. 
        !            84: 
        !            85: These changes in the xml are shown below and a screenshot of the new
        !            86: plot is provided as well. 
        !            87: 
        !            88: \begin{verbatim}
        !            89: 
        !            90:  <problem >
        !            91:  <script type="loncapa/perl" >
        !            92:  $amplitude = &random(3,5,1);
        !            93:  for ($x=-6.0; $x<=6.0; $x+=0.05) {
        !            94:      push @X,$x;
        !            95:      push @Y, $amplitude * sin($x);
        !            96:  }
        !            97:  </script >
        !            98:  <gnuplot font="medium" width="400" grid="on" height="300" 
        !            99:        border="on" fgcolor="x000000" 
        !           100:        alttag="dynamically generated plot" 
        !           101:        align="center" bgcolor="xffffff" transparent="off" >
        !           102:      <key title="" pos="top right" box="off" />
        !           103:      <ylabel >Y</ylabel >
        !           104:      <xlabel >X</xlabel >
        !           105:      <title >A sample plot</title >
        !           106:      <xtics end="5.0" location="border" start="-5.0" 
        !           107:             increment="1.0" mirror="on" />
        !           108:      <ytics end="6.0" location="border" start="-6.0" 
        !           109:             increment="1.0" mirror="on" />
        !           110:      <axis ymin="-6.0" ymax="6.0" xmin="-5.0" 
        !           111:             xmax="5.0" color="x000000" /> 
        !           112:      <curve linestyle="lines" pointtype="1" pointsize="1" name="f(x)"   
        !           113:          color="x000000">
        !           114:          <data >@X</data >
        !           115:          <data >@Y</data >
        !           116:      </curve >
        !           117:  </gnuplot >
        !           118:  <startouttext />
        !           119:  <br />
        !           120:  What is the amplitude of this function?
        !           121:  <endouttext />
        !           122:  <numericalresponse answer="$amplitude" >
        !           123:  <responseparam type="tolerance" default="5%" name="tol" 
        !           124:       description="Numerical Tolerance" />
        !           125:  <responseparam name="sig" type="int_range,0-16" default="0,15"  
        !           126:       description="Significant Figures" />
        !           127:  </numericalresponse > 
        !           128:  </problem >
        !           129: 
        !           130: \end{verbatim}
        !           131: 
        !           132: \includegraphics{dynamic_plot2}