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--- gibson:teaching:spring-2016:math445:lecture:scripts [2016/02/01 07:10]
gibson
+++ gibson:teaching:spring-2016:math445:lecture:scripts [2016/02/03 13:54] (current)
gibson [Logarithmic plots]
@@ Line 1: / Line 1: @@
-====== Math 445 lecture 3: scripts ======
+====== Math 445 lecture 3: scripts and plotting ======
 topics
 <code>
   Matlab scripting
-  plot, semilogy, semilogx, loglog
+  linestyles and plot modifiers:
-  xlabel, ylabel, title, legend
+    xlabel, ylabel, title, legend, axis, grid, clf,
-  linestyles
   load, save
-  what, pwd
+  plot, semilogy, semilogx, loglog
+  what, who, pwd, ls
 </code>
@@ Line 21: / Line 21: @@
 xlabel('x');
 legend('cos x', 'sin x');
+title('two trig functions')
+grid on
+axis equal
+axis([0 2*pi -1 1])
 </code>
-If you download this file and place it in your current working directory (folder), Matlab will be able to find it and execute it. In my case, Matlab is running in the directory ''/home/gibson/math445''. Here
+If you download this file and place it in your current working directory (folder), Matlab will be able to find it and execute it. In my case, Matlab is running in the directory ''/home/gibson/math445''.
 <code matlab>
@@ Line 36: / Line 40: @@
 MATLAB Code files in the current folder /home/gibson/math445
-plotsincos
+</code>
+When the script is run, Matlab opens a new figure window and draws the plot
+<code matlab>
 >> plotsincos % execute the plotsincos script
 </code>
+{{ :gibson:teaching:spring-2016:math445:sincos.png?direct&400 |}}
+===== Line styles and markers =====
+The above plotting script used the matlab **linestyle** codes '' 'b-' '' and '' 'r-' '' to generate blue and red curves for $\cos x$ and $\sin x$. Matlab's **help** function provides a pretty good description of how line and marker style codes work.
+<code matlab>
+>> help plot
+   % clip out irrelevant stuff here
+   Various line types, plot symbols and colors may be obtained with
+    plot(X,Y,S) where S is a character string made from one element
+    from any or all the following 3 columns:
+           b     blue          .     point              -     solid
+           g     green         o     circle             :     dotted
+           r     red           x     x-mark             -.    dashdot
+           c     cyan          +     plus               --    dashed
+           m     magenta       *     star             (none)  no line
+           y     yellow        s     square
+           k     black         d     diamond
+           w     white         v     triangle (down)
+                               ^     triangle (up)
+                               <     triangle (left)
+                               >     triangle (right)
+                               p     pentagram
+                               h     hexagram
+    For example, plot(X,Y,'c+:') plots a cyan dotted line with a plus
+    at each data point; plot(X,Y,'bd') plots blue diamond at each data
+    point but does not draw any line.
+ </code>
+===== Plot modifiers =====
+Some helpful commands for modifying plots
+<code matlab>
+xlabel('foo') % add an x label
+ylabel('bar') % add a y label
+title('baz')  % add a title
+legend('first', 'second', 'third') % add a legend with these labels
+axis on       % turn on axes and ticks (default)
+axis off      % turn off axes and ticks
+axis square   % make the plot square
+axis equal    % scale the x and y axes the same
+axis([xmin xmax ymin ymax]) % force these specific bounds on the axes
+grid on       % turn on grid markers
+grid off      % turn off grid markers
+hold on       % hold the current plot; the next plot will be plotted on top of this one
+hold off      % release the current plot; the next plot will erase this one
+clf           % clear figure (erase current plot)
+figure(2)     % open new figure window, numbered 2
+</code>

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