对流方程各种格式代码matlab5页

1、对流方程偏微分方程的数值解法用迎风格式解对流方程function u = peYF(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1);if a>0    for j=1:(n+M)        u0(j) = IniU(minx+(j-M-1)*h);    endelse       for j=1:(n+M)  

2、0;     u0(j) = IniU(minx+(j-1)*h);    endend   u1 = u0;for k=1:M    if a>0         for i=(k+1):n+M            u1(i) = -dt*a*(u0(i)-u0(i-1

3、)/h+u0(i);        end    else        for i=1:n+M-k            u1(i) = -dt*a*(u0(i+1)-u0(i)/h+u0(i);        end  

4、60; end    u0 = u1;endif a>0    u = u1(M+1):M+n);else    u = u1(1:n);endformat long;用拉克斯-弗里德里希斯格式解对流方程function u = peHypbLax(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1);for j=1:(n+2*M)        u0(j) = IniU(min

5、x+(j-M-1)*h);end u1 = u0;for k=1:M    for i=k+1:n+2*M-k        u1(i) = -dt*a*(u0(i+1)-u0(i-1)/h/2+(u0(i+1)+u0(i-1)/2;    end    u0 = u1;endu = u1(M+1):(M+n);format short;用拉克斯-温德洛夫格式解对流方程function u = peLaxW(a,dt,n,mi

6、nx,maxx,M)format long;h = (maxx-minx)/(n-1);for j=1:(n+2*M)        u0(j) = IniU(minx+(j-M-1)*h);end u1 = u0;for k=1:M    for i=k+1:n+2*M-k        u1(i) = dt*dt*a*a*(u0(i+1)-2*u0(i)+u0(i-1)/2/h/h - .  

7、                 dt*a*(u0(i+1)-u0(i-1)/h/2+u0(i);    end    u0 = u1;endu = u1(M+1):(M+n);format short;用比姆-沃明格式解对流方程function u = peBW(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1);for

8、j=1:(n+2*M)        u0(j) = IniU(minx+(j-2*M-1)*h);end u1 = u0;for k=1:M    for i=2*k+1:n+2*M        u1(i) = u0(i)-dt*a*(u0(i)-u0(i-1)/h-a*dt*(1-a*dt/h)* .         &#

9、160;  (u0(i)-2*u0(i-1)+u0(i-2)/2/h;    end    u0 = u1;endu = u1(2*M+1):(2*M+n);format short;用Richtmyer多步格式解对流方程function u = peRich(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1);for j=1:(n+4*M)        u0(j) = IniU(minx+(j-2*

10、M-1)*h);end u1 = u0;for k=1:M    for i=2*k+1:n+4*M-2*k        tmpU1 = -dt*a*(u0(i+2)-u0(i)/h/4+(u0(i+2)+u0(i)/2;        tmpU2 = -dt*a*(u0(i)-u0(i-2)/h/4+(u0(i)+u0(i-2)/2;      

11、0;         u1(i) = -dt*a*(tmpU1-tmpU2)/h/2+u0(i);    end    u0 = u1;endu = u1(2*M+1):(2*M+n);format short;用拉克斯-温德洛夫多步格式解对流方程function u = peMLW(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1);for j=1:(n+2*M)   &

12、#160;    u0(j) = IniU(minx+(j-M-1)*h);end u1 = u0;for k=1:M    for i=k+1:n+2*M-k        tmpU1 = -dt*a*(u0(i+1)-u0(i)/h/2+(u0(i+1)+u0(i)/2;        tmpU2 = -dt*a*(u0(i)-u0(i-1)/h/2+(u0(i)+u0(i-1)/2

13、;                u1(i) = -dt*a*(tmpU1-tmpU2)/h+u0(i);    end    u0 = u1;endu = u1(M+1):(M+n);format short;用MacCormack多步格式解对流方程function u = peMC(a,dt,n,minx,maxx,M)format long;h = (maxx-minx)/(n-1

14、);for j=1:(n+2*M)    u0(j) = IniU(minx+(j-M-1)*h);end u1 = u0;for k=1:M    for i=k+1:n+2*M-k        tmpU1 = -dt*a*(u0(i+1)-u0(i)/h+u0(i);        tmpU2 = -dt*a*(u0(i)-u0(i-1)/h+u0(i-1);  

15、;              u1(i) = -dt*a*(tmpU1-tmpU2)/h/2+(u0(i)+tmpU1)/2;    end    u0 = u1;endu = u1(M+1):(M+n);format short;用拉克斯-弗里德里希斯格式解二维对流方程的初值问题function u = pe2LF(a,b,dt,nx,minx,maxx,ny,miny,maxy,M)%啦-佛format

16、 long;hx = (maxx-minx)/(nx-1);hy = (maxy-miny)/(ny-1);for i=1:nx+2*M    for j=1:(ny+2*M)        u0(i,j) = Ini2U(minx+(i-M-1)*hx,miny+(j-M-1)*hy);    endend u1 = u0;for k=1:M    for i=k+1:nx+2*M-k   &#

17、160;    for j=k+1:ny+2*M-k            u1(i,j) = (u0(i+1,j)+u0(i-1,j)+u0(i,j+1)+u0(i,j-1)/4 .                 -a*dt*(u0(i+1,j)-u0(i-1,j)/2/hx . &#

18、160;               -b*dt*(u0(i,j+1)-u0(i,j-1)/2/hy;        end    end    u0 = u1;endu = u1(M+1):(M+nx),(M+1):(M+ny);format short;      

19、      用拉克斯-弗里德里希斯格式解二维对流方程的初值问题function u = pe2FL(a,b,dt,nx,minx,maxx,ny,miny,maxy,M)%近似分裂format long;hx = (maxx-minx)/(nx-1);hy = (maxy-miny)/(ny-1);for i=1:nx+4*M    for j=1:(ny+4*M)        u0(i,j) = Ini2U(minx+(i-2*M-

20、1)*hx,miny+(j-2*M-1)*hy);    endend u1 = u0;for k=1:M    for i=2*k+1:nx+4*M-2*k        for j=2*k-1:ny+4*M-2*k+2            tmpU(i,j) = u0(i,j) - a*dt*(u0(i+1,j)-u0(i-1,j)/2/hx + .