<html> <head> <title>Gri: Mathematics</title> </head> <body bgcolor="#FFFFFF" text="#000000" link="#0000EE" vlink="#551A8B" alink="FF0000"> <!-- newfile Mathematics.html "Gri: Mathematics" "Programming Gri" --> <!-- @node Mathematics, rpn Mathematics, Loops, Programming --> <a name="Mathematics" ></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="Programming.html#Programming" shape="rect" coords="516,2,532,24" href="Programming.html#Programming"> <area alt="Gri: Loops" shape="rect" coords="557,2,573,24" href="Loops.html"> <area alt="Gri: Reverse Polish Mathematics" shape="rect" coords="581,2,599,24" href="ReversePolishMath.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: Reverse Polish Mathematics" shape="rect" coords="581,2,599,24" href="ReversePolishMath.html"></map> <h2>10.8: Mathematics</h2> Gri lets you do some simple mathematical manipulations on your column and grid data. <p> <h3>10.8.1: Column data</h3> The column operators are `<font color="#82140F"><code>=</code></font>', `<font color="#82140F"><code>+=</code></font>', `<font color="#82140F"><code>-=</code></font>', `<font color="#82140F"><code>*=</code></font>', `<font color="#82140F"><code>/=</code></font>', `<font color="#82140F"><code>^=</code></font>' (exponentiation) and `<font color="#82140F"><code>_=</code></font>' (logarithm). There must be spaces before and after the operators, but no space between the 2 letters of the operators. The operations may be applied not only to `<font color="#82140F"><code>x</code></font>' and `<font color="#82140F"><code>y</code></font>' as shown, but also to `<font color="#82140F"><code>z</code></font>' (used to hold data to be contoured or written as symbols), and `<font color="#82140F"><code>u</code></font>' and `<font color="#82140F"><code>v</code></font>' (used to store vector fields). <p> The axis scales are <b>not</b> changed by mathematical operations on the columns, regardless of whether the scales were set manually or by Gri command (see <a href="AxisScaling.html#AxisScaling">Axis Scaling</a>). <p> Elements of columns are available by the `<font color="#82140F"><code>@</code></font>' reverse polish operator (see <a href="ReversePolishMath.html#rpnMathematics">rpn Mathematics</a>). <p> Examples: <ul> <li> To multiply all the x data by 10, use `<font color="#82140F"><code>x *= 10</code></font>'; to add 5 to each y-value, use `<font color="#82140F"><code>y += 5</code></font>'. <li> To set all the y data to 10, do `<font color="#82140F"><code>y = 10</code></font>'. (This will only work if you've already read column data.) </ul> <p> <h3>10.8.2: Grid data</h3> Various commands let you alter grid data as used in contouring (see <a href="ContourPlots.html#ContourPlots">Contour Plots</a>). Possible commands are as follows. <p> <TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%"> <TR> <TD> <PRE> <font color="#82140F"> grid data = number grid data += number grid data -= number grid data *= number grid data /= number grid data ^= number # take data to power 'number' grid data _= number # take log base 'number' grid x = number grid x += number #... others as in `grid data' grid y = number grid y += number #... others as in `grid data' </font></PRE> </TD> </TR> </TABLE> <p> <h4>10.8.2.1: Image data</h4> Various commands let you alter image data (see <a href="Images.html#Images">Images</a>.). Possible commands are as follows. <p> <TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%"> <TR> <TD> <PRE> <font color="#82140F"> image += number image -= number image *= number image /= number image ^= number # power image _= number # logarithm </font></PRE> </TD> </TR> </TABLE> <p> <h4>10.8.2.2: Image grayscale/colorscale</h4> Various commands let you alter image data (see <a href="Images.html#Images">Images</a>). Possible commands are as follows. <p> <TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%"> <TR> <TD> <PRE> <font color="#82140F"> image grayscale += number image grayscale -= number image grayscale *= number image grayscale /= number image grayscale ^= number # power image grayscale _= number # logarithm image colorscale += number image colorscale -= number image colorscale *= number image colorscale /= number image colorscale ^= number # power image colorscale _= number # logarithm </font></PRE> </TD> </TR> </TABLE> <p> <h4>10.8.2.3: Variables</h4> Possible commands are: <p> <TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="100%"> <TR> <TD> <PRE> <font color="#82140F"> .variable. = number .variable. += number .variable. -= number .variable. *= number .variable. /= number .variable. ^= number # power .variable. _= number # logarithm </font></PRE> </TD> </TR> </TABLE> <p> </table> <img src="./resources/bottom_banner.gif" usemap="#navigate_bottom" border="0"> </body> </html>
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