MATLAB

:

MATLAB

n MATLAB

n

ScilabOctave

n

2

MATLAB3

u

>> a=1, b=2, c=a+b a = 1. b = 2. c = 3.

>> a=1+2+3 ... +4+5 a = 15

u

MATLAB4

function c = test1(a,b) c = a + b

u M-file

>> edit filename >> edit test1.m test1.m

>> test1(a,b) ans = 3.

MATLAB5

u n % % n

>> a=1, b=3; n

MATLABC

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>> x=[1; 2; 3] x = 1. 2. 3.

: :

linspace>> linspace(1,9,5) ans = 1. 3. 5. 7. 9.

>> A=[1 2 3; 4 5 6; 7 8 10] A = 1. 2. 3. 4. 5. 6. 7. 8. 10.

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AijA(i,j) A = 1. 2. 3. 4. 5. 6. 7. 8. 10. >> A(2,2) ans = 5. Am,:)A(:,n)>> A(2,:) ans = 4. 5. 6. >> A(:,1) ans = 1. 4. 7.

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>> A=[1 2 ;3 4] A = 1. 2. 3. 4. >> B=[5 6 ;7 8] B = 5. 6. 7. 8.

+ >> A + B ans = 6. 8. 10. 12. - >> A - B ans = - 4. - 4. - 4. - 4. * >> A * B ans = 19. 22. 43. 50.

A>> A^2 ans = 7. 10. 15. 22. ' >> A' ans = 1. 3. 2. 4.

A, B

inv(A) * B >> A B ans = -3. -4. 4. 5. / A * inv(B) >> A / B ans = 3. - 2. 2. - 1.

Windows

A .* B

Mac option+

9

~

&&

|| shift +

n MATLAB l

u sin(x), log(x) l l

n >> x = 1.0; y = sin(x) >> [y1,y2,...] = func(x1,x2,...)

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x y sin(1.0)y

1. >> edit test2 2.

3. test2.m 4. >> a = 5; b = 2; c = 1; [r,s] = test2(a,b,c)

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function [x,y] = test2(a,b,c) x = a + b; y = a c;

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function [x,y] = test2(a,b,c) x = a + b; y = a c;

: test2

function

u aba + b, a b, a b, a / b test3

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MATLAB>> x=[1 2] x = 1. 2. >> sin(x) ans = 0.8414710 0.9092974 >> cos(x) ans = 0.5403023 - 0.4161468 >> tan(x) ans = 1.5574077 - 2.1850399

>> log(x) ans = 0. 0.6931472 >> exp(x) ans = 2.7182818 7.3890561

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A = 1. 2. 3. 4. >> R=inv(A) R = - 2. 1. 1.5 - 0.5 mn1 >> d=ones(2,3) d = 1. 1. 1. 1. 1. 1.

mn >> d=zeros(2,1) d = 0. 0. mn>> E=eye(2) E = 1. 0. 0. 1.

(1)16

>> x=linspace(0,2*pi,100);>> plot(x,sin(x));>> plot(x,cos(x));

plotFigure plot

FigureSave as jpg

(2)17

>> ezplot('sin(x)',[0,3])

ezplotFigure hold onhold off

>> hold on >> ezplot('sin(x)',[0,6.28]) >> ezplot('cos(x)',[0,6.28])

(1)18

02

46

810

02

46

8102

1.5

1

0.5

0

0.5

1

1.5

2

>> t=linspace(0,10,40); >> [x,y]=meshgrid(t,t); >> z=sin(x)+cos(y/2); >> mesh(x,y,z);

tmeshgridxy z=sin(x)+cos(y/2) mesh

(2)19

>> ezplot3('sin(t)','cos(t)','t)

ezplot3 ezplot3(x,y,z,[min,max])min < t < max x = x(t), y = y(t),z = z(t) 0 < t < 2

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zeros

ones

eye

diag

magic 1 n^2 n n

rand A = rand(n) (0,1) n n

randn A = randn(n) n n

linspace y = linspace(a,b) a b. 100 y y = linspace(a,b,n) a b n y

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(mldivide)

X = A B AX = B X X = inv(A) * B Windows

/ (mrdivide) X = A / B XB = A X X = A * inv(B)

det

rank

lu [L,U,P] = lu(A) P*A = L*U L U P

qr [Q,R] = qr(A) A m n A = Q*R m n R m m Q

eig d = eig(A) A [X,D] = eig(A) X D

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sin exp e

log10 logsqrt

round

minAmin(A) A A min(A) A

maxA max(A) A A max(A) A

meanA mean(A) A A mean(A) A

stds = std(X) X (1) Xstd(X) X

sumA sum(A) A sum(A) A

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MATLAB

MATLAB M

func1func1.m

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A=[3 2 7; 1 6 3; 1 0 6]; b=[3 ;-2 ;1]; x=A b

>> edit linear1.mAx=b

function y =mean1(x) n = length(x); y = sum(x)/n;

x

>> linear1 x = 1.6000 -0.5500 -0.1000

>> x=[1 4 7 10] x = 1 4 7 10 >> mean1(x) ans = 5.5000

>> edit mean1.m

Macoption+

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for for end

while while end

if, elseif, else if end

switch, case case

switch case otherwise end

for

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for XYZ1 for X=Y:Z end XYZW for X=Y:W:Z end

i1101i for i=1:10 disp(i); % disp(x)x end

for i=1:2:10 110210

for i=10:-1:1 101-11

for

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for i=1:n disp(i); end

for i=n:-1:1 disp(i); end

for2.m

function s = sum1(a) n = length(a); s = 0; for i=1:n s = s + a(i); end

sum1.m>> x = [1 4 5 2 7]; >> t = sum1(x)

>> n = 10; >> for1

>> n = 10; >> for2

for1.m

for1. n1n1

for3.m

2. 1n for4 3. dot1

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>> n=7; >> for3 1 3 5 7

while

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Eps = 1; while 1+Eps > 1 Eps = Eps/2; end Eps = Eps*2

while

eps1.m

Eps1

Eps/2

1.0

>> eps1 Eps = 2.2204e-16

if

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p.9 x 10k if x >= 10 k = k + 1; end ifelse elseif if elseif else end

if if1.m if2.m

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if a > 4 disp(b); end

function c = if2(a,b) if a > b c = a + b; else c = a - b; end

>> a = 3; b = 5; >> c = if2(a,b)

>> a = 3; b = 5; >> if1

switch

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function evenodd(n) switch mod(n,2) case 0 disp(even number'); case 1 disp(odd number'); otherwise disp(error'); end

case

evenodd.m

mod(x,y) x mod y 2even odd

(1)

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MATLAB f(x) = ex sin(10x) >> f=inline('exp(-x)*sin(10*x)) f(3) >> f(3) ans = -0.0492

(2)

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f(x)xf(x)* >> f=inline('exp(-x).*sin(10*x)') x >> x=[1 2 3]; >> f(x) ans = -0.2001 0.1236 -0.0492 f(x)[0,7] >> x=0:0.01:7; >> plot(x,f(x))

1. : MATLAB 2. : MATLAB/Scilab

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