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du/dx+dv/dx=0
u=dn/dx
v=-dm/dx
du/dx=-exp(-x)+n*m/(m+n)
±ß½çÌõ¼þºÍ³õÖµÌõ¼þ
u(p)=0,u(0)=v(p),v(0)=0
n(0)=q
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y(1)=n,y(2)=m,y(3)=u,y(4)=v
y'(1)=y(3),y'(2)=-y(4),y'(3)=-exp(-x)+y(1)*y(2)/(y(1)+y(2)),y'(4)=exp(-x)-y(1)*y(2)/(y(1)+y(2))

·½³ÌMÎļþ
function dydx=ivode(x,y)
dydx=[y(3);-y(4);-exp(-x)+2*y(1)*y(2)/(2*y(2)+y(1));exp(-x)-2*y(1)*y(2)/(2*y(2)+y(1))];

±ß½çÌõ¼þMÎļþ
function res=ivbc(ya,yb)
res=[ya(1)-q;ya(4);yb(3);ya(3)-yb(4)];

command:
solinit=bvpinit(linspace(0,1,10),[1 1 0 0]);
sol=bvp4c(@ivode,@ivbc,solinit);
??? Error using ==> bvp4c
Unable to solve the collocation equations -- a singular Jacobian encountered

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acnes

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xiegangmai(½ð±Ò+1): ллӦÖú£¡ 2011-12-21 22:25:39
acnes(½ð±Ò+20): ¡ï¡ï¡ïºÜÓаïÖú àÅ£¬·Ç³£¸Ðл»ý¼«µÄ»Ø¸´£¡ 2011-12-22 15:56:40
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CODE:
??? Undefined function or variable 'q'.

Error in ==> ivbc at 2
res=[ya(1)-q;ya(4);yb(3);ya(3)-yb(4)];

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2Â¥2011-12-20 18:38:48
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acnes

½ð³æ (ÕýʽдÊÖ)

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??? Error using ==> bvp4c
Unable to solve the collocation equations -- a singular Jacobian encountered
3Â¥2011-12-20 19:08:24
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû

wangyuewu08

ľ³æ (ÖøÃûдÊÖ)

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xiegangmai(½ð±Ò+1): лл²ÎÓ룡 2011-12-21 22:25:55
ÒýÓûØÌû:
3Â¥: Originally posted by acnes at 2011-12-20 19:08:24:
=¡£= ÎÒÒ²¸Ä³Éq=1£¬ÎªÉ¶»¹ÊÇÕâ¸ö½á¹ûÄØ¡£¡£¡£Ô­±¾ÎÒÔËËãµÄʱºòÒ²ÊÇÉ趨ÁËqÖµµÄ¡£
??? Error using ==> bvp4c
Unable to solve the collocation equations -- a singular Jacobian encountered

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