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chj787

½ð³æ (СÓÐÃûÆø)

[ÇóÖú] matlabÄâºÏÇóÖú

ÓÃmatlabÄâºÏÒ»¸ö·½³Ì£º
    y=(a+bx+cx^2+dx^3)exp(-bx)
x=[0.8,0.85,0.9,0.94,1,1.1,1.14,1.144,1.146,1.148,1.149,1.15,1.151,1.152,1.153,1.157,1.25,1.3,1.35,1.4,1.45,1.5,1.55,1.6,1.65,1.7,1.75,1.8,1.85,1.9,1.95,2,2.05,2.1,2.15,2.2,2.25,2.3,2.35,2.4];
y=[129698.6607,81517.14907,48462.38869,30160.54842,12625.39888,830.7904906,0,2.343989057,8.695584894,18.42928479,24.54823752,31.4946096,39.26181681,47.84108015,57.22581538,102.7141275,687.9234793,3872.493796,7589.20011,11578.99871,15654.88623,19681.73873,23751.25051,27388.0944,30756.13673,33816.1486,36542.19252,38921.37873,40955.22819,42660.53072,44067.23581,45213.10408,46138.07991,46880.36067,47474.18002,47948.97387,48329.25318,48634.92208,48881.88591,49082.65691];

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ÄâºÏ³£Êý£º a,b,c,d
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[ Last edited by chj787 on 2012-5-20 at 16:29 ]
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lgycjpcqu

½ð³æ (ÕýʽдÊÖ)

¡¾´ð°¸¡¿Ó¦Öú»ØÌû

¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï
¸Ðл²ÎÓ룬ӦÖúÖ¸Êý +1
xzhdty: ½ð±Ò+1, ллÁË 2012-05-22 06:01:48
chj787: ½ð±Ò+15, ¡ï¡ï¡ï¡ï¡ï×î¼Ñ´ð°¸, ·Ç³£¸Ðл£¡ÆÀ·ÖÍíÁË£¬Íò·Ö±§Ç¸~£¡ 2012-05-29 15:29:20
x=[0.8,0.85,0.9,0.94,1,1.1,1.14,1.144,1.146,1.148,1.149,1.15,1.151,1.152,1.153,1.157,1.25,1.3,1.35,1.4,1.45,1.5,1.55,1.6,1.65,1.7,1.75,1.8,1.85,1.9,1.95,2,2.05,2.1,2.15,2.2,2.25,2.3,2.35,2.4];
y=[129698.6607,81517.14907,48462.38869,30160.54842,12625.39888,830.7904906,0,2.343989057,8.695584894,18.42928479,24.54823752,31.4946096,39.26181681,47.84108015,57.22581538,102.7141275,687.9234793,3872.493796,7589.20011,11578.99871,15654.88623,19681.73873,23751.25051,27388.0944,30756.13673,33816.1486,36542.19252,38921.37873,40955.22819,42660.53072,44067.23581,45213.10408,46138.07991,46880.36067,47474.18002,47948.97387,48329.25318,48634.92208,48881.88591,49082.65691];
ybeta=inline('(beta(1)+beta(2)*x+beta(3)*x.^2+beta(4)*x.^3).*exp(-beta(2)*x)','beta','x');
beta=nlinfit(x,y,ybeta,[1e+004,0,-1e+004,1e+004]);
a=beta(1);
b=beta(2);
c=beta(3);
d=beta(4);
yy=(a+b*x+c*x.^2+d*x.^3).*exp(-b*x);
plot(x,yy,x,y,'*')
µ«ÊÇ»áÏÔʾ
Warning: The Jacobian at the solution is ill-conditioned, and some
model parameters may not be estimated well (they are not identifiable).
Use caution in making predictions.ËùÒÔ¿ÉÄÜ»¹ÐèÒª½øÒ»²½ÊÖ¶¯ÓÅ»¯£¬ÎÒ×öÄãºÎʱÓÃnlinfitÒ²¾­³£³öÏÖÕâ¸ö¾¯¸æ£¬ÆÚ´ýÓиßÊÖ½â´ð¡£
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3866678.20479525       
2.55862906421524       
-8281766.51676900       
4642226.52606192
Ï£ÍûÄܰﵽÄã
7Â¥2012-05-21 10:31:55
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû
²é¿´È«²¿ 12 ¸ö»Ø´ð

cactus586

½ð³æ (ÖøÃûдÊÖ)

Á÷À˹ýµÄÈË×ÜÊÇÏëÔÙ´Î̤ÉÏÂÃ;

¡¾´ð°¸¡¿Ó¦Öú»ØÌû

¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï ¡ï
¸Ðл²ÎÓ룬ӦÖúÖ¸Êý +1
xzhdty: ½ð±Ò+1, »¶Ó­³£À´³ÌÐòÓïÑÔ¿´¿´ 2012-05-21 05:57:43
chj787: ½ð±Ò+30, ¡ïÓаïÖú, 1 2012-05-24 21:55:56
×òÌì¿´µ½Ò»¸öÓÃMatLabÑÝ×࿨ٯµÄ ¿ÉÒÔÕ¾¶ÌÎÊÎÊËû
http://muchong.com/bbs/viewthread.php?tid=4519096
¾²Ë®Á÷Éî
2Â¥2012-05-20 16:40:48
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû

chj787

½ð³æ (СÓÐÃûÆø)

ÒýÓûØÌû:
2Â¥: Originally posted by cactus586 at 2012-05-20 16:40:48:
×òÌì¿´µ½Ò»¸öÓÃMatLabÑÝ×࿨ٯµÄ ¿ÉÒÔÕ¾¶ÌÎÊÎÊËû
http://muchong.com/bbs/viewthread.php?tid=4519096

лл£¡
3Â¥2012-05-20 17:59:36
ÒÑÔÄ   »Ø¸´´ËÂ¥   ¹Ø×¢TA ¸øTA·¢ÏûÏ¢ ËÍTAºì»¨ TAµÄ»ØÌû

lijie169

Í­³æ (ÖøÃûдÊÖ)

¡¾´ð°¸¡¿Ó¦Öú»ØÌû

¡ï ¡ï ¡ï ¡ï ¡ï
¸Ðл²ÎÓ룬ӦÖúÖ¸Êý +1
xzhdty: ½ð±Ò+2, »¶Ó­³£À´³ÌÐòÓïÑÔ 2012-05-21 05:58:00
chj787: ½ð±Ò+3, ¡ï¡ï¡ïºÜÓаïÖú 2012-05-29 15:30:03
CODE:
function f=fit(x,y)
f=lsqnonlin(@(a)fun(a,x,y),[1,1,1,1]');
function f1=fun(a,x,y)
f1=y-(a(1)+a(2)*x+a(3)*x.^2+a(4)*x.^3).*exp(-a(2)*x);
end
end

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4Â¥2012-05-20 18:08:21
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