<html> <head> <title>Gri: `differentiate' command</title> </head> <body bgcolor="#FFFFFF" text="#000000" link="#0000EE" vlink="#551A8B" alink="FF0000"> <!-- newfile Differentiate.html "Gri: `differentiate' command" "Gri Commands" --> <!-- @node Differentiate, Draw, Delete, List Of Gri Commands --> <a name="Differentiate" ></a> <img src="./resources/top_banner.gif" usemap="#navigate_top" border="0"> <table summary="top banner" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="150" valign="top"> <font size=-1> <br> Chapters: </br> <a href="Introduction.html">1: Introduction</a><br> <a href="SimpleExample.html">2: Simple example</a><br> <a href="InvokingGri.html">3: Invocation</a><br> <a href="GettingMoreControl.html">4: Finer Control</a><br> <a href="X-Y.html">5: X-Y Plots</a><br> <a href="ContourPlots.html">6: Contour Plots</a><br> <a href="Images.html">7: Image Plots</a><br> <a href="Examples.html">8: Examples</a><br> <a href="Commands.html">9: Gri Commands</a><br> <a href="Programming.html">10: Programming</a><br> <a href="Environment.html">11: Environment</a><br> <a href="Emacs.html">12: Emacs Mode</a><br> <a href="History.html">13: History</a><br> <a href="Installation.html">14: Installation</a><br> <a href="Bugs.html">15: Gri Bugs</a><br> <a href="TestSuite.html">16: Test Suite</a><br> <a href="Acknowledgments.html">17: Acknowledgments</a><br> <a href="License.html">18: License</a><br> <br> Indices:</br> <a href="ConceptIndex.html"><i>Concepts</i></a><br> <a href="CommandIndex.html"><i>Commands</i></a><br> <a href="BuiltinIndex.html"><i>Variables</i></a><br> </font> <td width="500" valign="top"> <map name="navigate_top"> <area alt="index.html#Top" shape="rect" coords="5,2,218,24" href="index.html#Top"> <area alt="ListOfGriCommands.html#ListOfGriCommands" shape="rect" coords="516,2,532,24" href="ListOfGriCommands.html#ListOfGriCommands"> <area alt="Gri: `delete' command" shape="rect" coords="557,2,573,24" href="Delete.html"> <area alt="Gri: About draw commands" shape="rect" coords="581,2,599,24" href="Draw.html"> </map> <map name="navigate_bottom"> <area alt="index.html#Top" shape="rect" coords="5,2,218,24" href="index.html#Top"> <area alt="Gri: About draw commands" shape="rect" coords="581,2,599,24" href="Draw.html"></map> <h3>9.3.8: `<font color="#82140F"><code>differentiate</code></font>'</h3> <!-- latex: \index{differentiate} --> <TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%"> <TR> <TD> <PRE> <font color="#82140F"> `differentiate {x|y wrt index|y|x} | {grid wrt x|y}' </font></PRE> </TD> </TR> </TABLE> <p> Differentiate column data or grid data. Only the `<font color="#82140F"><code>x</code></font>' and `<font color="#82140F"><code>y</code></font>' columns may be differentiated. They may be differentiated either with respect to (``wrt'') the index (forming a first difference) or with respect to the other column. The derivative is done with the backwards-difference algorithm. Grid data may differentiated with respect to `<font color="#82140F"><code>x</code></font>' direction or `<font color="#82140F"><code>y</code></font>' direction. Grid differentiation is done with a centred difference, with endpoints being assigned the derivative of the neighboring interior point (so that the second derivative is zero at the edges of the grid). <p> </table> <img src="./resources/bottom_banner.gif" usemap="#navigate_bottom" border="0"> </body> </html>