1
Matlab
:
1. .
2. () , OptimizationToolbox.
1.
1.1 Matlab
Matlab : , , , . , .
1.1.1
Matlab Workspace, , , :
plot -
loglog -
semilogx, semilogy -
polar -
1.1.1.1 plot
:
1. .
2. y().
3. plot .
( plot , . . ).
plot(Y)
plot(X1,Y1,...,Xn,Yn)
plot(X1,Y1,LineSpec,...,Xn,Yn,LineSpec)
plot(X1,Y1,LineSpec,'PropertyName',PropertyValue)
plot(axes_handle,X1,Y1,LineSpec,'PropertyName',PropertyValue)
h = plot(X1,Y1,LineSpec,'PropertyName',PropertyValue)
plot(y) y ; , plot(real(y), imag(y)). Y - , ; .
plot(x, y) , x , y - . X Y , :
Y , x , Y x;
X, y , X y;
X Y , Y X.
plot(x1, y1, s1, x2, y2, s2,...) y1(x1), y2(x2),..., . holdon, . " ". , . , , . -, . subplot. , . subplot , , , - ( ).
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plot plot(x, y, s1, x, y, s2) y(x) , s1 , .
, . , . plotyy, , .
FigureNo. 1 . , .
plot . MatLab .
1.1.1.2 loglog, semilogx, semilogy, polar
:
- loglog ( );
- semilogx ( );
- semilogy ( ).
loglog, semilogx semilogy , plot, .
polar.
1.1.1.3
Matlab , . , . plot (x(i), y(i)) , . Matlab Line. , . (; handles). plot(x, y, s) , , , s, , help.
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, , , .
: , , . gridon, xlabel, ylabel, title.
legend . , .
1.1.2
Matlab . z- , x y. . - ( plot3), - ( mesh surf). , mesh, - , , , EdgeColor surface. , surf, - , , ; FaceColor surface.
1.1.2.1 plot3
plot3(x, y, z)
plot3(X, Y, Z)
plot3(x, y, z, s)
plot3(x1, y1, z1, s1, x2, y2, z2, s2,...)
plot3 (...) plot(...).
plot3 (x, y, z), x, y, z - , x(i), y(i), z(i) .
plot3 (X, Y, Z), X, Y, Z - , x(i,:), y(i,:), z(i,:) .
plot3 (x, y, z, s) z(x, y), , , s, .
1.1.2.2 mesh
mesh(X, Y, Z, C) meshc(X, Y, Z, C) meshz(X, Y, Z, C)
mesh(x, y, Z, C) meshc(x, y, Z, C) meshz(x, y, Z, C)
mesh(Z, C) meshc(Z, C) meshz(Z, C)
mesh(X, Y, Z) meshc(X, Y, Z) meshz(X, Y, Z)
mesh(x, y, Z) meshc (x, y, Z) meshz(x, y, Z)
mesh(Z) meshc(Z) meshz(Z)
mesh (X, Y, Z, C) Z, X Y. C. EdgeColor surface. , [r g b] - , , . none, . flat, , . , . interp, .
mesh( x, y, Z, C) , X, Y , length(x) = n, length(y) = m, [m, n] = size(Z). {x(j), y(i), Z(i, j)}, x Z, y - .
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mesh (Z, C) , x = 1: n y = 1: m.
mesh (X, Y, Z), mesh(x, y, Z), mesh(Z) C = Z, .
meshc (...) .
meshz (...) , , .
h = mesh (...) h surface.
1.1.2.3 surf
surf , , . .
surf(Z)
surf(Z,C)
surf(X,Y,Z)
surf(X,Y,Z,C)
surf(...,'PropertyName',PropertyValue)
surf(axes_handles,...)
surfc(...)
h = surf(...)
surf , mesh, .
surf , . , surfl.
surfl . , , , . Matlab.
- , , ( ) . , colormap (copper), (- - colormap), , ( - - copper). surfl (X, Y, Z) surf(X,Y,Z) . , , , shadinginterp, , () (). .
1.1.2.4 meshgrid
[X, Y] = meshgrid(x, y)
[X, Y] = meshgrid(x)
[X, Y] = meshgrid (x, y) x-y X, Y, x y. X x, - y. , .
[X, Y] = meshgrid (x) [X, Y] = meshgrid (x, x).
1.1.3
Matlab , , contour3. , mesh, surf, meshc surfc . . contour3 , , , . ( levels) , ( ).
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contour(X,Y,Z) , xy, . , .
colorbar .
, , Matlab clabel. clabel : , , . clabel. contour, , , clabel .
contour ( , contour3, ) , , , .
xy, . contourf, contour.
2.
, OptimizationToolbox Matlab. :
→ min [-1.5;1.5]
2. → min, x [-1;1]
2.1
plot (.1). .
>>x=-1.5:0.0001:1.5;
>>y=cos(3*pi*x)+exp(-x*2)/3;
>> plot(x,y)
.1-
, .
, plot(x, y) , x , y - . Workspace(.2).
.2
Matlab min.
>> [y_min,n]=min(y)
y_min =
-0.9549
n =
, -0.9549, 25011. , -x, .
>>x_min=x(25011)
x_min =
1.0010
, 30001 -0.9549, x=1.0010.
2.2
:
1. .
2. .
3. Matlab, , mesh.
4. , , .
meshgrid, () ( , ) ( ).
, x [-1;1] (.2).
.
>>[X,Y] = meshgrid(-1:0.05:1);
>>Z =2*sin(2*pi*X).*cos(2.5*pi*Y).*(1-X.^2).*(1-Y);
>>mesh(X,Y,Z)
.2 -
meshc (.3).
>> [X,Y] = meshgrid(-1:0.05:1);
>> Z =2*sin(2*pi*X).*cos(2.5*pi*Y).*(1-X.^2).*(1-Y);
>>meshc(X,Y,Z)
.3
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, surf (.4).
>> [X,Y] = meshgrid(-1:0.05:1);
>> Z =2*sin(2*pi*X).*cos(2.5*pi*Y).*(1-X.^2).*(1-Y);
>> surf(X,Y,Z)
.3
, plot3
>> [X,Y] = meshgrid(-1:0.05:1);
>> Z =2*sin(2*pi*X).*cos(2.5*pi*Y).*(1-X.^2).*(1-Y);
>> plot3(X,Y,Z)
(.4).
.4
, Z, min(min(Z)). min (Z(:)).
min_Z=min(Z(:)) min_Z=min(minZ)
:
[row_min,col_min]=find(Z==min(Z(:)))
[row_min,col_min]=find(Z==min_Z), row- y, col x.
,
>> [X,Y] = meshgrid(-1:0.05:1);
>> Z =2*sin(2*pi*X).*cos(2.5*pi*Y).*(1-X.^2).*(1-Y);
>>min_Z=min(Z(:))
min_Z =
-3.3750
>>[row_min,col_min]=find(Z==min_Z)
row_min =
col_min =
>>xx=[-1:0.05:1];
>>xx_min=xx(16)
xx_min =
-0.2500
>>yy=[-1:0.05:1];
>>yy_min=yy(5)
yy_min =
-0.8000
>> Z =2*sin(2*pi*(-0.25))*cos(2.5*pi*(-0.8)).*(1-(-0.25)^2).*(1-(-0.8))
Z =
-3.3750
3.
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