Octave

2011 1

1 41.1 Octave ? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.2 Octave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3 Octave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.4 ( C++) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 42.1 Octave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Octave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Octave 73.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4 114.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134.6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

liuqiang@coer.zju.edu.cn

1

2

5 155.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155.2 Multiple graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165.3 Multiple figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6 Octave I 186.1 Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

7 207.1 if...else . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207.2 switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227.3 for . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227.4 while . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

8 Octave II 238.1 1: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248.3 2: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

9 269.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 279.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309.5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

10 31

11 Ax = b 33

12 3312.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3312.2 3D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3312.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3312.4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

13 35

14 3514.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3614.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

3

15 Octave 37

A 40

B 40

1 4

1

1.1 Octave ?

Octave Matlab Octave

Octave Octave Octave Octave

Octave Octave J.W.Eation GNU General Public Licence Octave Matlab

1.2 Octave

Octave Octave Mathemat-icaMaple ()

1.3 Octave

Octave Maltab NASA ; Jaguar Racing F1 ;Sheffield Octave

1.4 ( C++)

C++ C++ Octave C++ Octave

2

2.1 Octave

Octave UNIX octave octave

GNU Octave, version 3.2.4Copyright (C) 2009 John W. Eaton and others.This is free software; see the source code for copying conditions.There is ABSOLUTELY NO WARRANTY; not even for MERCHANTABILITY orFITNESS FOR A PARTICULAR PURPOSE. For details, type `warranty'.

2 5

Octave was configured for "i486-pc-linux-gnu".

Additional information about Octave is available at http://www.octave.org.

Please contribute if you find this software useful.For more information, visit http://www.octave.org/help-wanted.html

Report bugs to (but first, please readhttp://www.octave.org/bugs.html to learn how to write a helpful report).

For information about changes from previous versions, type `news'.Octave:1>

Octave Octave:>1 Octave Octave quit exit

2.2 Octave

Octave Octave

octave:##>2+2

,

ans=4

2.3

Octave 1 C++ Octave

octave:##> exp(1)ans=2.71813

1.2 sin(40 + ln(2.42)),

octave:##>1.2*sin(40*pi/180+log(2.4^2))ans=0.76618

:

1. 1.2 sin

2 6

1: cos ()sin ()tan ()exp (ex)log e log10 10 sinh tanh cosh acos acosh asin asinh atan atan2 1

atanh abs ()sign round floor ceil fix 0 rem

3 OCTAVE 7

2. /180 pi Octave

3. logln

Octave

3 Octave

Octave Octave C++

Octave

3.1

Octave deg

octave:##> deg=pi/180deg=0.017453

( C++) Octave Octave

octave:##>1.2*sin(40*deg+log(2.4^2))ans=0.76618

Octave ans

octave:##> new=3*ansnew=2.2985

new 3 0.76618 Octave 2.2985

Octave a A Octave pii j(i = j =

1()) Octave

sin cos

3 OCTAVE 8

octave:##> who*** dynamically linked functions:dispatch*** currently compiled functions:rem*** local user variables:deg new

clear :

clear name

name

3.2

Octave format

octave:##> format long

octave 15 octave helpformat format long deg

octave:##> degdeg=0.0174532925199433

octave:##> format short

octave Octave 13142.6 = 1.31426 104, Octave

1.3143e+04 Octave Octave

(e.g.3+4i), Octave

(Inf) 0

(NaN) 0 0

Inf NaN Inf NaN

3.3

Octave 12.25

12.25 = 1 101 + 2 100 + 2 101 + 5 102 (1)

1101.01 = 1 23 + 1 22 + 0 21 + 1 20 + 0 21 + 1 22 = 12.25 (2)

3 OCTAVE 9

0 1, (bit)

octave:##> 1-0.2-0.2-0.2-0.2-0.2ans=5.5511e-17

0.2 (0.2=0.0011001100...) 1/3 Octave()

3.4

Octave Octave

octave:##> save anyname

anyname.mat (.mat octave ) Octave Octave

octave:##> load anyname

octave:##>save filename var1 var2 ...

deg

octave:##> save degconv deg

deg degconv.mat

octave:##> load degconv

Octave

3.5

Octave ()

Octave

3 OCTAVE 10

3.6

Octave Octave

help commandname

octave:1> help sqrt`sqrt' is a built-in function

-- Mapping Function: sqrt (X)Compute the square root of each element of X. If X is negative, acomplex result is returned. To compute the matrix square root, see*note Linear Algebra::.

See also: realsqrt

Additional help for built-in functions and operators isavailable in the on-line version of the manual. Use the command`doc ' to search the manual index.

Help and information about Octave is also available on the WWWat http://www.octave.org and via the help@octave.orgmailing list.

help -iOctave Up,Next, Previous

arithmetic

octave:##> help -i arithmetic

q octave

3.7

( bug )

Ctrl-C

4 11

3.8

Octave Octave Octave Octave

4

(array) Octave (vector)

( ) (...)

4.1

[]

octave:##> a=[1 4 5]a=

1 4 5octave:##> b=[2,1,0]

b=2 1 0

octave:##> c=[4;7;10]c=

4710

;

octave:##> a=[1 4 5]a=

1 4 5octave:##> d=[a 6]

d=1 4 5 6

4.2

4 12

octave:##> e=2:6e=

2 3 4 5 6

octave a : b : c

octave:##> e=2:0.3:4e=

2.0000 2.3000 2.6000 2.9000 3.2000 3.5000 3.8000

octave

4.3

Octave

octave:##> v=1:1000

q Octave b

Octave

octave:##> more off

octave:##> more on

4.4

Octave 2

2: zeros(M,N) MN ones(M,N) MN linspace(x1,x2,N) N , x1

x2logspace(x1,x2,N) N

10x1 10x2

zeros ones M N

4 13

4.5

() 1, C C++ 0

octave:##> a=[1:2:6 -1 0]a=

1 3 5 -1 0

octave:##> a(3)ans=

5

octave:##> a(3:5)ans=

5 -1 0octave:##> a(1:2:5)

ans=1 5 0

4.6

Octave C++ 2, for Octave for Octave a

octave:1> a=[1:2:6 -1 0]a =

1 3 5 -1 0

octave:2> a*2ans =

2 6 10 -2 0

+

* / a1a2a3

. b1b2b3

=a1b1a2b2a3b3

(3)

5 14

.

octave:3> b=1:5b =

1 2 3 4 5

octave:4> a.*bans =

1 6 15 -4 0

octave:5> b.^2ans =

1 4 9 16 25

octave:6> 2.^bans =

2 4 8 16 32octave:7> a.^b

ans =

1 9 125 1 0

(element-by-element) Octave 60 sin

octave:8> angles=[0:pi/3:2*pi]angles =

0.00000 1.04720 2.09440 3.14159 4.18879 5.23599 6.28319

octave:9> y=sin(angles)y =

0.00000 0.86603 0.86603 0.00000 -0.86603 -0.86603 -0.00000

5 15

-1

-0.5

0

0.5

1

0 1 2 3 4 5 6 7

1: y = sin(x) 60

5

Octave GNUPLOT23plot(x,y), x,y

octave:10> plot(angles,y)

1 Octave y

octave:1> angles=linspace(0,2*pi,100);octave:2> y=sin(angles);octave:3> plot(angles,y);

linspace 0 2 100

5.1

Octave plot

octave:4> plot(angles,y,'ro');

3 ( help plot ) title,xlabel ylabel xy

octave:7> title('Graph of y=sin(x)')octave:8> xlabel('Angle')octave:9> ylabel('Value')

2www.gnuplot.org3 gnuplot

5 16

3: plot ( help plot),( Matlab )w . - m o : c x x -. r + + g * b s y d k v

< > p h

replot grid

octave:##> grid on

2

5.2 Multiple graphs

plot x y

octave:##>plot(angles,ycangles,cos(angles));octave:##>legend('Sine','Cosine');

legend 3 plot

hold plot

octave:13> plot(angles,y,'.')octave:14> hold onoctave:15> plot(angles,cos(angles),'g-')octave:16> legend('Sine','Cosine')

hold off

5.3 Multiple figures

figure

octave:##> figure

plot

5 17

-1

-0.5

0

0.5

1

0 1 2 3 4 5 6

Val

ue

Angle

Graph of y=sin(x)

2: y = sin(x)

-1

-0.5

0

0.5

1

0 1 2 3 4 5 6 7

SineCosine

3: y = sin(x) y = cos(x)

6 OCTAVE I 18

octave:##> plot(angles,tan(angles))

octave:##> figure(1)

5.4

Octave/Gnuplot Octave print help print print

octave:##> print('graph1.eps','-deps')

eps

octave:##> print('graph1.png','-dpng')

png

6 Octave I

Octave Octave Octave Octave Octave Octave Octave

Octave .m (e.g. run.m) M Octave

6.1 Path 4 Octave path Octave

Octave path Octave path ( linux /usr/share/octave) (pwd) path

octave:##> path. /usr/share/octave/3.2.4/m/help/home/kasion/bin/octavecode /usr/share/octave/3.2.4/m/plot/usr/local/share/octave/site-m /usr/share/octave/3.2.4/m/path/usr/lib/octave/3.2.4/site/oct/i486-pc-linux-gnu /usr/share/octave/3.2.4/m/time/usr/lib/octave/3.2.4/oct/i486-pc-linux-gnu /usr/share/octave/3.2.4/m/io/usr/share/octave/3.2.4/m /usr/share/octave/3.2.4/m/audio/usr/share/octave/3.2.4/m/deprecated /usr/share/octave/3.2.4/m/signal/usr/share/octave/3.2.4/m/set /usr/share/octave/3.2.4/m/general

4

6 OCTAVE I 19

/usr/share/octave/3.2.4/m/linear-algebra /usr/share/octave/3.2.4/m/elfun/usr/share/octave/3.2.4/m/testfun /usr/share/octave/3.2.4/m/specfun/usr/share/octave/3.2.4/m/miscellaneous /usr/share/octave/3.2.4/m/pkg/usr/share/octave/3.2.4/m/special-matrix /usr/share/octave/3.2.4/m/polynomial...

octave path addpath homebob/bin/octave path ,

octave:##> addpath('/home/bob/bin/octave');

savepath path

octave:##> savepath;

path doc path help path

6.2

(,emacs, vi, notepad) Octave

octave:##> edit

emacs5 edit run.m edit run Octave

%Script to calculate and plot a rectified sine wave t=linspace(0,10,100); y=abs(sin(t)); % The abs command makes all negative numbers positive plot(t,y); title('Rectified Sine Wave'); xlabel('t');

% Octave rectsin.m Octave rectsin

octave:##> rectsin

octave

6.3

Octave what :

5edit Octave

7 20

0

0.2

0.4

0.6

0.8

1

0 2 4 6 8 10

t

Rectified Sine Wave

4: rectsin

octave:##> whatM-files in directory /home/kasion/tmp:rectsin.m...

Octave rectsin

>> help rectsinScript to calculate and plot a rectified sine wave

Octave help

7

Octave Octave

7.1 if...else

if Octave if

if expressionstatements

elseif expressionstatements

7 21

4:

== if x==y= if x =y> if x>y>= if x>=y< if x a=0;b=2;octave:##> if a>b

c=3else

c=4endc=4

if Octave end Octave

1 0

octave:##> 1==2ans=

0octave:##> pi>exp(1) & sqrt(-1)==i

ans=1

4 C++

7 22

7.2 switch

if/elseif switch

switch xcase x1statements

case x2statementsotherwisestatements

end

switch x case statements Octave switch C++ break Octave statements swith otherwise

octave:##> a=1;octave:##> switch a

case 0disp('a is zero');

case 1disp('a is one');

otherwisedisp('a is not a binary digit');

enda is one

disp e.g. disp(a) a

7.3 for

for Octave for for for

for variable=vectorstatements

end

vector ( 4.2 )

octave:##> for n=1:5nf(n)=factorial(n);

end

8 OCTAVE II 23

octave:##> disp(nf)1 2 5 24 120

for octave nf(n)

7.4 while

Octave while

while expressionstatements

end

octave:##> x=1;octave:##> while 1+x>1

x=x/2;end

octave:##>xx=

1.1102e-16

8 Octave II

Octave

Octave reference Octave

function [output1,output2,...]=name(input1,input2,...)

M M sind() sind.m M

Octave

8.1 1:

Octave sin(d/180*pi) d sind(d)(sine in degrees) sind.m

8 OCTAVE II 24

function s=sind(x)% SIND(x) Calculates sine(x) in degreess=sin(x*pi/180);endfunction

1. Line1 Octave sind

2. Line2 Octave help sind Octave

3. Line3 x s

4. Line4 Octave endfunction Octave return ()

8.2

sind.m M .m path (), Octave sind

octave:##> help sindSIND(x) Calculates sine(x) in degrees

octave:##> sin(0)ans=

0octave:##> sin(45)

ans=0.7071

octave:##> t=sin([30 60 90])t=

0.5000 0.8660 1.0000

x sin

8 OCTAVE II 25

8.3 2:

y =

0 t < t01 otherwise: t0

function y=ustep(t,t0)%USTEP(t,t0) unit step at t0% A unit step is defined as% 0 for t=t0[m,n]=size(t);%Check that this is a vector, not a matrix i.e. (1 x n) or (m x 1)if m~=1 & n ~=1

error('T must be a vector');endy=zeros(m,n); %Initialise output arrayfor k=1:length(t)if t(k)>=t0

y(k)=1; % Otherwise, leave it at zero, which is correctendifendforendfunction

1. Line1 ustep t t0 y

2. Line2-5

3. Line6 ustep t size Octave

4. Line7-10 error

5. Line11 t

6. Line12 t y for length t

9 26

-1

-0.5

0

0.5

1

1.5

2

-1 0 1 2 3 4

y

t

Example of function Ustep

5:

7. Line13-15 t < t0 y t >= t0 y = 1

(m,n k ) y ustep.m

octave:##> t=-1:0.1:4;octave:##> v=ustep(t,0)-ustep(t,1);octave:##> plot(t,v);octave:##> axis([-1 4 -1 2]);

5

9

m n m n 2 3 [5 7 9

1 3 2

]

Octave

octave:##> A=[5 7 9-1 3 -2]

A=

9 27

5 7 9-1 3 -2

octave:##> B=[2 0; 0 -1;1 0]octave:##> B=

2 00 -11 0

octave:##> C=[1:3;8:-2:4]C=

1 2 38 6 4

>D=[1 2 3];>D=[D; 4 5 6]>D=[D; 7 8 9]>D=

1 2 44 5 67 8 9

9.1

*

> A*Bans=19 -7-4 -3

> B*Cans=2 4 6-8 -6 -41 2 3

> A*Cerror operator *: nonconformant arguments (op1 is 2x3, op2 is 2x3)

,

(l m) (m n) (l n) (4)

9 28

octave:1> A=[1 2;2 1]A =

1 22 1

octave:2> A^2ans =

5 44 5

A2 = A A.* :

octave:1> A=[1 2;2 1]A =

1 22 1

octave:2> B=[1 2;3 4]B =

1 23 4

octave:3> A.*Bans =

1 46 4

octave:4> A.^2ans =

1 44 1

octave:5> 2.^Aans =

2 44 2

9 29

9.2

A AT octave

octave:6> A=[5 7 9;-1 3 -2]A =

5 7 9-1 3 -2

octave:7> A'ans =

5 -17 39 -2

9.3

Octave ones zeros 1 0 t I Octave eye

octave:8> I=eye(4)I =

Diagonal Matrix

1 0 0 00 1 0 00 0 1 00 0 0 1

octave:9> I*[5;8;2;0]ans =

5820

Octave diag :

9 30

octave:10> diag([-1 7 2])ans =

Diagonal Matrix

-1 0 00 7 00 0 2

diag

octave:11> diag(A)ans =

53

octave:12> E=[]E = [](0x0)

9.4

Octave

octave:22> B=[2 0;0 -1;1 0]B =

2 00 -11 0

octave:23> comp=[eye(3) B;A zeros(2,2)]comp =

1 0 0 2 00 1 0 0 -10 0 1 1 05 7 9 0 0-1 3 -2 0 0

10 31

9.5

()

octave:24> J=[1 2 3 4> 5 6 7 8> 11 12 13 10]J =

1 2 3 45 6 7 811 12 13 10

octave:25> J(1,1)ans = 1octave:26> J(2,3)ans = 7octave:27> J(1:2,4)% rows 1-2, column 4ans =

48

octave:28> J(3,:) % row 3, all columnsans =

11 12 13 10

octave:29> J(3,2:3)=[-1 0]J =

1 2 3 45 6 7 811 -1 0 10

10

Octave ( 5 ) size ( AA1 = A1A = I)

10 32

5: eye zeros ones rand diag inv det trace eig rank null Calculate a basis for the null space of a matrixrref Perform Gaussian elimination on an augmented matrixlu Calculate the LU decomposition of a matrixqr Calculaate the QR decompotitionof a matrixsvd Calculate the SVD of a matrixpinv Calculate the pseudoinverse of a matrix

tt inv

octave:3> A=[3 0 4;0 1 -2;2 1 3]A =

3 0 40 1 -22 1 3

octave:4> inv(A)ans =

0.71429 0.57143 -0.57143-0.57143 0.14286 0.85714-0.28571 -0.42857 0.42857

octave:5> A*inv(A)ans =

1.00000 0.00000 0.000000.00000 1.00000 0.00000-0.00000 0.00000 1.00000

11 AX = B 33

Octave det

octave:6> det(A)ans = 7

11 Ax = b

12

Octave GNUPLOT3D Octave GNUPLOT

12.1

tt subplot

subplot(row,columns,select)

subplot subplot

octave:25> x=linspace(-10,10);octave:26> subplot(2,1,1)octave:27> plot(x,sin(x));octave:28> subplot(2,1,2)octave:29> plot(x,sin(x)./x)

6 sinc

12.2 3D

Octave 3D 3D tt plot3 x,y tt z

octave:11> z = [0:0.05:5];octave:12> plot3 (cos(2*pi*z), sin(2*pi*z), z, ";helix;")

7 3D xlabel ylabel zlabel z 3D 3

12.3

3D 6 Octave view ( help view )

12 34

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

-10 -5 0 5 10

-1

-0.5

0

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1

-10 -5 0 5 10

6: subplot

helix

-1

-0.5

0

0.5

1

-1

-0.5

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0.5

10

1

2

3

4

5

7: plot3

LMB+motion +LMB+motion (Rotate axes6)

6:

13 35

0

2

4

6

8

10

12

0 2 4 6 8 10 12

contourmeshz

02

46

810

12

02

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810

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02

46

810

12

02

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810

12-1

-0.5

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02

46

810

12

02

46

810

12-1

-0.5

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1

surf

8: 3D

3D f(x, y)Octave meshgird

octave:17> x=2:0.2:4;octave:18> y=1:0.2:3;octave:19> [X,Y]=meshgrid(x,y);% make the grid

12.4

X,Y

f(x, y) = (x 3)2 (y 2)2

Octave

octave:20> Z=(X-3).^2-(Y-2).^2;octave:21> subplot(2,2,1);surf(Z);title('surf')octave:22> subplot(2,2,2);mesh(Z);title('mesh')octave:23> subplot(2,2,3);meshz(Z);title('meshz')octave:24> subplot(2,2,4);contour(Z);title('contour')

8

13

14

Octave Octave

14 36

(z = a+ bi)imag areal babs r = |z|conj z = a biangle = sin(a

b)

7:

octave:40> z1=4-3iz1 = 4 - 3i

tt i tt j Octave (

1)

octave:41> z2=1+3jz2 = 1 + 3i

octave:42> z2-z1ans = -3 + 6ioctave:43> z1+z2ans = 5octave:44> z2/z1ans = -0.20000 + 0.60000ioctave:45> z1^2ans = 7 - 24i

Octave 7 Octave sin(x) ex

14.1

Octave tt plot Argand ( x y )

octave:3> plot(z1,'*',z2,'*')octave:4> axis([-5 5 -5 5])

9

14.2

Octave roots tt root

x5 + 2x4 5x3 + x+ 3 = 0

15 OCTAVE 37

-4

-2

0

2

4

-4 -2 0 2 4

9:

octave:##> c=[1 2 -5 0 1 3];

tt roots

octave:12> roots([1 2 -5 0 1 3])ans =

-3.44726 + 0.00000i1.17303 + 0.39021i1.17303 - 0.39021i-0.44940 + 0.60621i-0.44940 - 0.60621i

15 Octave

Unix , Octave . , . Octave , ., hello :

#!octave-interpreter-name -qf# a sample Octave programprintf ("Hello, world!\n");

15 OCTAVE 38

( octave-interpreter-name Octave , /usr/bin/octave). #! . hello (e.g. chmod u+x hello),

hello

. #! , . #! Octave . Octave, -qf ,-q , f ~/.octaverc 7.

Octave , . Octave argv . :

#! /bin/octave -qfprintf ("%s\n", program_name ());arg_list = argv ();for i = 1:narginprintf (" %s\n", arg_list{i});

endforprintf ("\n");

test , :

kasion@tmp:$ chmod u+x testkasion@tmp:$ ./test arg1 arg2 arg3

:

kasion@tmp:$ ./test arg1 arg2 arg3testarg1arg2arg3

test PATH (/usr/bin /home/kasion/bin ), ls,cd test, shell script,., .

1.3000000000e+00 2.9549292750e+00 2.9349509600e+001.3102040816e+00 2.9454196710e+00 2.9248815610e+001.3204081633e+00 2.9359134520e+00 2.9148026660e+001.3306122449e+00 2.9264083650e+00 2.9047117190e+00

...7, Octave , path , -f ,Octave

.

15 OCTAVE 39

, TE TM .

D = C

d2neffd2 (5)

Getdistetm :

!/usr/bin/octave -q# no comments...#print the messagesclear all;printf("Programe name :%s\n", program_name ());printf("Processing ....\n");format long;#basic constantsC=3e2; # light speed in freespace [um/ps]#load the dataarglist=argv ();...#load the databuffer=load(arglist{1});lam=buffer(:,1);neffte=buffer(:,2);nefftm=buffer(:,3);

#caculate the dipersionfitorder=4;Pte=polyfit(lam,neffte,fitorder);Ptm=polyfit(lam,nefftm,fitorder);for k=1:(fitorder-1)P2te(k)=(fitorder+1-k)*(fitorder-k)*Pte(k);P2tm(k)=(fitorder+1-k)*(fitorder-k)*Ptm(k);endd2neffte=polyval(P2te,lam);....outdata=[lam Dispersionte Dispersiontm];

#save the resultsave("-ascii",outfile,"outdata");#plot and save the figure;figure;plot(lam,Dispersionte,'k:','LineWidth',2,lam,Dispersiontm,'r-','LineWidth',2);...grid on;

A 40

print(figurename,'-dpng','-S680,500');printf("Done!\n");# End of the script

kasion@tmp:$ Getdistetm 800x500_bp_mode_neffr.dat

. shell ,

kasion@tmp:$ for file in `ls *neffr.dat`; do Getdistetm $file; done

neffr.dat .

A

:

Octave :http://www.gnu.org/software/octave/docs.htmlOctave:http://ljk.imag.fr/membres/Christophe.Prudhomme/courses/octave/octave-refcard-a4.pdfOctave :http://octave.1599824.n4.nabble.com/

B

Dr.P.J.G Long , Acknowledgements:

This document has been produced as a tutoial to acompany the version of Octave suppliedon the Cambidge-MIT Institute(CMI)8 funded Multidisciplinary Design Project (MDP)9 ResourceCD.

The text of this tutorial has been adapted from the student notes developed by Dr. PaulSmith from the Cambridge University Engineering Department for a 2nd year Introduction toMatlab sourse. Conversion from Paul Smiths original to this current document has be relativeeasy with in many cases needing only to exchange

Octave for Matlab in the text

the prompt and precise format of the answers given in the example scripts

removal of specific course administration.

However in number of cases there are significant differences, e.g. graphical performance (Gnuplotis assumed to be the output plugin for Octave), where changes have had to be made.

Any success of this tutorial is a major result of the the backgroud work carried out by TimFroggatt in setting up the MDP resource distribution and requests from Gareth Wilson, the authorof the RED Tools web interface for Octave scipts, for additional information and scripts.

8CMI-www.cambridge-mint.org9MDP-http://www-mdp.eng.cam.ac.uk

http://www.gnu.org/software/octave/docs.htmlhttp://ljk.imag.fr/membres/Christophe.Prudhomme/courses/octave/octave-refcard-a4.pdfhttp://octave.1599824.n4.nabble.com/

B 41

Significaant reference has been made to the resources generated and maintianed by John Eatonand his team at www.octave.org. As indicated above, the tutorial is heavily based on Paul SmithsOriginal in which he acknowledges advice and help from Roberto Cipolla, Richard Prager, HughHunt, Maurice Ringer, David Mansergh and Martin Szummer.

B 42

2011 , : Matlab Octave, , ,Octave , , LATEX , kile error , , , ::liuqiang@coer.zju.edu.cn,

mailto:liuqiang@coer.zju.edu.cn

Octave?OctaveOctave(C++)

OctaveOctave

Octave

Multiple graphsMultiple figures

OctaveIPath

if...elseswitchforwhile

OctaveII1:2:

Ax=b3D

Octave