diff options
Diffstat (limited to 'doc/kmplot/using.docbook')
| -rw-r--r-- | doc/kmplot/using.docbook | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/doc/kmplot/using.docbook b/doc/kmplot/using.docbook new file mode 100644 index 00000000..88092ad8 --- /dev/null +++ b/doc/kmplot/using.docbook @@ -0,0 +1,321 @@ +<chapter id="using-kmplot"> +<title>Using &kmplot;</title> + +<para>&kmplot; deals with named functions, which can be specified in +terms of Cartesian coordinates (called <quote>explicit +functions</quote>), polar coordinates or as parametric functions. To +enter a function, choose +<menuchoice><guimenu>Plot</guimenu><guimenuitem>Edit +Plots...</guimenuitem> </menuchoice>. You can also enter new functions +in the <guilabel>Function equation</guilabel> text box in the main +&kmplot; window. The text box can handle explicit and polar +functions. Each function you enter must have a unique name (&ie;, a +name that is not taken by any of the existing functions displayed in +the list box). A function name will be automatically generated if you +do not specify one.</para> + +<para>For more information on &kmplot; functions, see <xref +linkend="reference"/>. +</para> + +<screenshot> +<screeninfo>Here is a screenshot of the &kmplot; welcome window</screeninfo> + <mediaobject> + <imageobject> + <imagedata fileref="main.png" format="PNG"/> + </imageobject> + <textobject> + <phrase>Screenshot</phrase> + </textobject> + </mediaobject> +</screenshot> + +<sect1 id="function-types"> +<title>Function Types</title> + +<sect2 id="explicit-functions"> +<title>Explicit Functions</title> +<para>To enter an explicit function (&ie;, a function in the form y=f(x)) into &kmplot;, just enter it in the +following form: +<screen> +<userinput><replaceable>f</replaceable>(<replaceable>x</replaceable>)=<replaceable>expression</replaceable></userinput> +</screen> +Where: +<itemizedlist> +<listitem><para> + <replaceable>f</replaceable> is the name of the function, and can be any +string of letters and numbers you like, provided it does not start with any of +the letters x, y or r (since these are used for parametric and polar +functions).</para> +</listitem> + +<listitem><para> +<replaceable>x</replaceable> is the x-coordinate, to be used in the expression +following the equals sign. It is in fact a dummy variable, so you can use any +variable name you like, but the effect will be the same.</para> +</listitem> + +<listitem> +<para><replaceable>expression</replaceable> is the expression to be plotted, +given in appropriate syntax for &kmplot;. See <xref linkend="math-syntax"/>. +</para> +</listitem> + +</itemizedlist> +</para> +<para>As an example, to draw the graph of y=x<superscript>2</superscript>+2x, +enter the following into the functions dialog of &kmplot;: +<screen> +f(x)=x^2+2x +</screen> +</para> +</sect2> + +<sect2 id="parametric-functions"> +<title>Parametric Functions</title> +<para>Parametric functions are those in which the x and y coordinates are +defined by separate functions of another variable, often called t. To enter a +parametric function in &kmplot;, follow the procedure as for an explicit +function, but prefix the name of the function describing the x-coordinate with +the letter x, and the function describing the y-coordinate with the letter +y. As with explicit functions, you may use any variable name you wish for the +parameter. To draw a parametric function, you must go to <guimenu>Plot</guimenu><guimenuitem>New Parametric Plot...</guimenuitem>. A function name will be created automatic if you do not specify one.</para> +<para>As an example, suppose you want to draw a circle, which has parametric +equations x=sin(t), y=cos(t). In the &kmplot; functions dialog, do the +following: +<orderedlist> +<listitem><para>Open the parametric plot dialog with +<menuchoice><guimenu>Plot</guimenu><guimenuitem>New Parametric Plot...</guimenuitem> +</menuchoice>.</para> +</listitem> +<listitem><para>Enter a name for the function, say, +<userinput>circle</userinput>, in the <guilabel>Name</guilabel> +box. The names of the x and y functions change to match this name: the +x function becomes <guilabel>xcircle(t)</guilabel> and the y function +becomes <guilabel>ycircle(t)</guilabel>.</para> +</listitem> +<listitem> +<para>In the x and y boxes, enter the appropriate equations, &ie;, +<guilabel>xcircle(t)=</guilabel><userinput>sin(t)</userinput> and +<guilabel>ycircle(t)=</guilabel><userinput>cos(t)</userinput>.</para> +</listitem> +</orderedlist> +Click on <guibutton>OK</guibutton> and the function will be drawn. +</para> +<para>You can set some further options for the plot in this dialog: +<variablelist> + +<varlistentry> +<term><guilabel>Hide</guilabel></term> +<listitem> +<para>If this option is selected, the plot is not drawn, but &kmplot; +remembers the function definition, so you can use it to define other +functions.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><guilabel>Custom plot minimum-range</guilabel></term> +<term><guilabel>Custom plot maximum-range</guilabel></term> +<listitem> +<para>If this options are selected, you can change the maximum and +minimum values of the parameter t for which the function is plotted +using the <guilabel>Min:</guilabel> and <guilabel>Max:</guilabel> +boxes.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><guilabel>Line width:</guilabel></term> +<listitem> +<para>With this option you can set the width of the line drawn on the +plot area, in units of 0.1mm.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><guilabel>Color:</guilabel></term> +<listitem> +<para>Click on the color box and pick a color in the dialog that +appears. The line on the plot will be drawn in this color.</para> +</listitem> +</varlistentry> +</variablelist> +</para> +</sect2> + +<sect2 id="polar-functions"> +<title>Entering Functions in Polar Coordinates</title> + +<para>Polar coordinates represent a point by its distance from the origin +(usually called r), and the angle a line from the origin to the point makes +with the x-axis (usually represented by the Greek letter theta). To enter +functions in polar coordinates, use the menu entry +<menuchoice><guimenu>Plot</guimenu><guimenuitem>New Polar Plot...</guimenuitem> +</menuchoice>. In the box labeled <guilabel>r</guilabel>, complete the +function definition, including the name of the theta variable you want +to use, ⪚, to draw the Archimedes' spiral r=theta, enter: +<screen> +<userinput> +(theta)=theta +</userinput> +</screen> +so that the whole line reads <quote>r(theta)=theta</quote>. Note that +you can use any name for the theta variable, so +<quote>r(foo)=foo</quote> would have produced exactly the same output. +</para> + +</sect2> + +</sect1> + +<sect1 id="combining-functions"> +<title>Combining Functions</title> +<para>Functions can be combined to produce new ones. Simply enter the functions +after the equals sign in an expression as if the functions were variables. For +example, if you have defined functions f(x) and g(x), you can plot the sum of f +and g with: +<screen> +<userinput> +sum(x)=f(x)+g(x) +</userinput> +</screen> +</para> +<para>Note that you can only combine functions of the same type, ⪚ an +explicit function cannot be combined with a polar function.</para> +</sect1> + +<sect1 id="function-appearance"> +<title>Changing the appearance of functions</title> + +<para>To change the appearance of a function's graph on the main plot +window, select the function in the <guilabel>Edit Plots</guilabel> +dialog, and click on the <guibutton>Edit</guibutton> button. In the +dialog which appears, you can change the line width in the text box, +and the color of the function's graph by clicking on the color button +at the bottom. If you are editing an explicit function, you will see a +dialog with three tabs. In the first one you specify the equation of +the function. The <guilabel>Derivatives</guilabel> tab lets you draw +the first and second derivative to the function. With the +<guilabel>Integral</guilabel> tab you can draw the integral of the +function which is calculated using Euler's method. </para> +<para>Another way to edit a function is to right click on the +graph. In the popup menu that appears, choose +<guibutton>Edit</guibutton></para> + +<para>For more information on the popup menu, see <xref +linkend="popupmenu"/>. +</para> +</sect1> + +<sect1 id="popupmenu"> +<title>Popup menu</title> + +<para>When right-clicking on a plot function or a single-point parametric plot function a popup menu will appear. +In the menu there are five items available:</para> + +<variablelist> +<varlistentry> +<term><menuchoice><guimenuitem>Hide</guimenuitem> +</menuchoice></term> +<listitem> +<para>Hides the selected graph. Other plots of the graph's function will still be shown.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Remove</guimenuitem> +</menuchoice></term> +<listitem> +<para>Removes the function. All its graphs will disappear.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Edit</guimenuitem> +</menuchoice></term> +<listitem> +<para>Shows the editor dialog for the selected function.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Copy</guimenuitem> +</menuchoice></term> +<listitem> +<para>Copies the graph to another running &kmplot; instance.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Move</guimenuitem> +</menuchoice></term> +<listitem> +<para>Moves the graph to another running &kmplot; instance.</para> +</listitem> +</varlistentry> +</variablelist> + +<para>For plot functions the following four items are also available:</para> + +<variablelist> +<varlistentry> +<term><menuchoice><guimenuitem>Get y-Value</guimenuitem> +</menuchoice></term> +<listitem> +<para>Opens a dialog in which you can find the y-value corresponding to +a specific x-value. The selected graph will be highlighted in the +dialog. Enter an x value in the <guilabel>X:</guilabel> box, and click +on <guibutton>Calculate</guibutton> (or press &Enter;). The corresponding y +value will be shown under <guilabel>Y:</guilabel>. +</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Search for Minimum Value</guimenuitem> +</menuchoice></term> +<listitem> +<para>Find the minimum value of the graph in a specified range. The +selected graph will be highlighted in the dialog that appears. Enter +the lower and upper boundaries of the region in which you want to +search for a minimum, and click <guibutton>Find</guibutton>. The x and +y values at the minimum will be shown.</para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Search for Maximum Value</guimenuitem> +</menuchoice></term> +<listitem> +<para>This is the same as <guimenuitem>Search for Minimum +Value</guimenuitem> above, but finds maximum values instead of minima. </para> +</listitem> +</varlistentry> + +<varlistentry> +<term><menuchoice><guimenuitem>Calculate Integral</guimenuitem> +</menuchoice></term> +<listitem> +<para>Select the x-values for the graph in the new dialog that appears. +Calulates the integral and draws the area between the graph and the x-axis in the +selected range in the color of the graph.</para> +</listitem> +</varlistentry> +</variablelist> + + +</sect1> + + +</chapter> +<!-- +Local Variables: +mode: sgml +sgml-minimize-attributes:nil +sgml-general-insert-case:lower +sgml-indent-step:0 +sgml-indent-data:nil +sgml-parent-document:("index.docbook" "BOOK" "CHAPTER") +End: +--> |