Differences

This shows you the differences between two versions of the page.

--- octave:octave [2008/06/25 09:56] – created deva
+++ octave:octave [2009/04/23 13:54] (current) – deva
@@ Line 1: / Line 1: @@
-=====Octave=====
+=====Octave syntax and library overview=====
-====if then else end====
+====Installing packages====
-<code octave>
+Fetch the package files from [[http://octave.sourceforge.net/|octaveforge]].
-a = 1
+Then create (or add to) the file ~/.octaverc the following content:
+<code matlab>
+addpath(genpath('~/octave'))
+</code>
+And run ''pkg install packagename-1.0.0.tar.gz'' or whatever the package is called from inside octave.
+Now the package should be available.
+====plotting====
+<code matlab>
+h = [1,2,3,4,5];
+plot(h);
+xlabel("some numbers");
+print("myfile.pdf", "-dpdf");
+</code>
+This code plots a a vector with a label on the x-axis, and exports it to a pdf file.
+<code matlab>
+h=wavread('h.wav');
+hfft=abs(fft(h));
+semilogx(hfft(1:end/2))
+</code>
+This code loads an audiofile, and plots its frequency spectrum on a logartihmical scale.
+====function====
+<code matlab>
+function retval = myfunction(param1, param2)
+  retval = param1 + param2;
+end;
+</code>
+====strings====
+<code matlab>
+mystring = 'hello world'; % create string
+sizeof(mystring) % get length of string
+mystrilyng2 = [ mystring, 'fisk']; % concatenate two strings
+</code>
+sizeof on works in octave. in matlab the length of a string cannot be obtained!
+====string array====
+<code matlab>
+myemptyarray = {}; % create empty string array.
+myarray = { 'hello', 'world' }; % create array with two strings.
+myarray(1) % prints 'hello'
+myarray(3) = 'blah'; %inserts another string into the array.
+sizeof(myarray) % get number of elements
+sizeof(myarray(1)) %get length of first string
+% Iterate strings in string array
+for str = myarray
+  disp(str)
+end
+</code>
+Note: Arrays are 1-based, not 0-based as they usually are in real programming languages.
+Note: sizeof is an octave-only function. size can be used to get the array size in matlab.
+====if then else====
+<code matlab>
+a = 1;
 if a == 1
+  "a is one"
 end;
+if a == 2
+  "a is two"
+else
+  "a is not two"
+end;
+</code>
+====for while====
+<code matlab>
+list = 1:10
+for i = list
+  i
+end;
+a = 1;
+while a < 11
+  a
+  a = a + 1;
+end;
+</code>
+====switch case====
+<code matlab>
+yesno = "yes"
+switch yesno
+case {"Yes" "yes" "YES" "y" "Y"}
+  value = 1;
+case {"No" "no" "NO" "n" "N"}
+  value = 0;
+case "blah"
+  value = 42;
+otherwise
+  error ("invalid value");
+endswitch
 </code>
+Note: In matlab the ''endswitch'' should be replaced by ''end''
 ====Links====