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Diff for /loncom/homework/templates/Rnumerical.problem between versions 1.1 and 1.3

version 1.1, 2009/04/18 23:43:54 version 1.3, 2009/07/06 17:12:47
Line 1 Line 1
 <problem>  <problem>
   
 <script type="loncapa/perl">  <script type="loncapa/perl">
 $seed=&random(1,500,1);  $seed=&random(1,500,1);
 $n=&random(15,25,1);  $n=&random(15,25,1);
 $offset=&random(2,5,0.1);  $offset=&random(2,5,0.1);
 $slope=&random(0.6,2.5,0.1);  $slope=&random(0.6,2.5,0.1);
 # construct a data set using R  # construct a data set using R
 $data=&cas('R',"set.seed($seed);x<-1:$n;w<-1+sqrt(x)/2;data.frame(x=x,y=$offset+$slope*x+rnorm(x)*w);");  # dump is for debugging, print to screen to see data structure
 # separate into an x and a y vector  ($data,$dump)=&cas_hashref('R',"set.seed($seed);x<-1:$n;w<-1+sqrt(x)/2;data.frame(x=x,y=$offset+$slope*x+rnorm(x)*w);");
 @datatable=split(/\s+/gs,$data);  @x=&cas_hashref_array($data,'x');
 for ($i=0;$i<2*$n;$i+=2) {  @y=&cas_hashref_array($data,'y');
     push(@x,$datatable[$i]);  
     push(@y,$datatable[$i+1]);  
 }  
 $datax=join(',',@x);  $datax=join(',',@x);
 $datay=join(',',@y);  $datay=join(',',@y);
 # calculate the right answer using R  # calculate the right answer using R
 ($intercept,$slope)=split(/\s+/,&cas('R',"x<-c($datax);y<-c($datay);dataset<-data.frame(x=x,y=y);fm<-lm(y~x,data=dataset);array(coef(fm),dim=2);"));  ($answerdata,$dump)=&cas_hashref('R',"x<-c($datax);y<-c($datay);dataset<-data.frame(x=x,y=y);fm<-lm(y~x,data=dataset);");
 $answer="$slope*x+$intercept";  $answer=&cas_hashref_entry($answerdata,'coefficients','x').'*x+'.&cas_hashref_entry($answerdata,'coefficients','(Intercept)');
 </script>  </script>
 <gnuplot width="400" solid="0" plotcolor="monochrome" gridlayer="off" bmargin="default" font="9" alttag="dynamically generated plot" bgcolor="xffffff" texfont="22" transparent="off" plottype="Cartesian" rmargin="default" gridtype="Cartesian" minor_ticscale="0.5" fontface="sans-serif" grid="on" align="right" texwidth="93" height="300" border="on" samples="100" fgcolor="x000000" major_ticscale="1" tmargin="default" lmargin="default" fillstyle="empty">  
   <startouttext />
   Consider the plotted data set.<br />
   <endouttext />
   
   <gnuplot width="400" solid="0" plotcolor="monochrome" gridlayer="off" bmargin="default" font="9" alttag="dynamically generated plot" bgcolor="xffffff" texfont="22" transparent="off" plottype="Cartesian" rmargin="default" gridtype="Cartesian" minor_ticscale="0.5" fontface="sans-serif" grid="on" align="left" texwidth="93" height="300" border="on" samples="100" fgcolor="x000000" major_ticscale="1" tmargin="default" lmargin="default" fillstyle="empty">
     <curve linestyle="points" linetype="solid" color="x000000" pointtype="3" limit="closed" pointsize="2" linewidth="1">      <curve linestyle="points" linetype="solid" color="x000000" pointtype="3" limit="closed" pointsize="2" linewidth="1">
         <data>@x</data>          <data>@x</data>
         <data>@y</data>          <data>@y</data>
     </curve>      </curve>
       
 </gnuplot>  </gnuplot>
   
 <startouttext />  <startouttext />
 Consider the data set  <br />
 <pre>$data</pre>  
   
 Give a linear function approximating the data.<br />  Give a linear function approximating the data.<br />
 <tt>y(x)=</tt>  <tt>y(x)=</tt>
 <endouttext />  <endouttext />
 <formularesponse answer="$answer" samples="x@1:$n#20">  
   <formularesponse id="11" answer="$answer" samples="x@1:$n#20">
     <responseparam name="tol" default="2%" description="Numerical Tolerance" type="tolerance" />      <responseparam name="tol" default="2%" description="Numerical Tolerance" type="tolerance" />
     <textline size="25" readonly="no" />      <textline size="25" readonly="no" />
       
 </formularesponse>  </formularesponse>
   
 </problem>  </problem>
Removed from v.1.1  
changed lines
  Added in v.1.3

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