How to get out of this error:'You can not subscript a table using only one subscript. Table subscripting requires both row and variable subscripts', while data fitting in NRTL thermodynamic model

1 次查看（过去 30 天）
Ashish Kundaliya
Ashish Kundaliya 2020-1-13
评论： Ashish Kundaliya 2020-1-14
I am trying to data fit in NRTL thermodynamic model where i have Five input variables which i wrote it in one matrix xd, and one output accroding to that five input that i wrote it in yd column matrix. where 'a' is Constants that i want to get for this Data. alpha is another constant which value remains same and which value input we also gave.
below is my code:
clear all;
clc;
alpha=0.3;
xd(:,1) = readtable('Data2.xlsx','Sheet',1,'Range','A2:A41')
xd(:,2) = readtable('Data2.xlsx','Sheet',1,'Range','B2:B41')
xd(:,3) = readtable('Data2.xlsx','Sheet',1,'Range','C2:C41')
xd(:,4) = readtable('Data2.xlsx','Sheet',1,'Range','D2:D41')
xd(:,5) = readtable('Data2.xlsx','Sheet',1,'Range','E2:E41')
yd = readtable('Data2.xlsx','Sheet',2,'Range','A2:A41')
a0=[-68.7129 -5.3215 0.0615 -13.7754 -7.7847 -73.611 -0.4944 -1.5439 -0.0677 1.5985 1.5728 0.4826];
for K = 1 : height(yd)
options = optimoptions('lsqcurvefit','Algorithm','trust-region-reflective','MaxFunEvals',800000,'MaxIter',300000,'TolX',1e-10,'TolFun',1e-10)
lb = [];
ub = [];
[a{K}, resnorm{K}]= lsqcurvefit( @(a,xd) curvefit_multiobjective_two(a, xd{K}), a0, xd{K} , yd{K}, lb, ub, options);
end
C=[0 a(1) a(2); a(3) 0 a(4); a(5) a(6) 0]
D=[0 a(7) a(8); a(9) 0 a(10); a(11) a(12) 0]
where NRTL data is also attached below:(Pl. note that actual data is not listed for security purposes)
File name for data is : Data2.xlsx
the calling function code is written below:
function yd=curvefit_multiobjective_two(a,xd)
alpha=0.3;
tow11=0;
tow12=(a(1)+(a(7)./(xd(:,1))));
tow13=(a(2)+(a(8)./(xd(:,1))));
tow21=(a(3)+(a(9)./(xd(:,1))));
tow22=0;
tow23=(a(4)+(a(10)./(xd(:,1))));
tow31=(a(5)+(a(11)./(xd(:,1))));
tow32=(a(6)+(a(12)./(xd(:,1))));
tow33=0;
G11=exp(-alpha.*tow11);
G12=exp(-alpha.*tow12);
G13=exp(-alpha.*tow13);
G21=exp(-alpha.*tow21);
G22=exp(-alpha.*tow22);
G23=exp(-alpha.*tow23);
G31=exp(-alpha.*tow31);
G32=exp(-alpha.*tow32);
G33=exp(-alpha.*tow33);
a1=((xd(:,2).*tow11.*G11)+(xd(:,3).*tow21.*G21)+((1-xd(:,2)-xd(:,3)).*tow31.*G31))./((xd(:,2).*G11)+(xd(:,3).*G21)+((1-xd(:,2)-xd(:,3)).*G31));
a2=((xd(:,2).*G11)./((xd(:,2).*G11)+(xd(:,3).*G21)+((1-xd(:,2)-xd(:,3)).*G31))).*(tow11-(((xd(:,2).*tow11.*G11)+(xd(:,3).*tow21.*G21)+((1-xd(:,2)-xd(:,3)).*tow31.*G31))./((xd(:,2).*G11)+(xd(:,3).*G21)+((1-xd(:,2)-xd(:,3)).*G31))));
a3=((xd(:,3).*G12)./((xd(:,2).*G12)+(xd(:,3).*G22)+((1-xd(:,2)-xd(:,3)).*G32))).*(tow12-(((xd(:,2).*tow12.*G12)+(xd(:,3).*tow22.*G22)+((1-xd(:,2)-xd(:,3)).*tow32.*G32))./((xd(:,2).*G12)+(xd(:,3).*G22)+((1-xd(:,2)-xd(:,3)).*G32))));
a4=(((1-xd(:,2)-xd(:,3)).*G13)./((xd(:,2).*G13)+(xd(:,3).*G23)+((1-xd(:,2)-xd(:,3)).*G33))).*(tow13-(((xd(:,2).*tow13.*G13)+(xd(:,3).*tow23.*G23)+((1-xd(:,2)-xd(:,3)).*tow33.*G33))./((xd(:,2).*G13)+(xd(:,3).*G23)+((1-xd(:,2)-xd(:,3)).*G33))));
a5=((xd(:,2).*tow12.*G12)+(xd(:,3).*tow22.*G22)+((1-xd(:,2)-xd(:,3)).*tow32.*G32))./((xd(:,2).*G12)+(xd(:,3).*G22)+((1-xd(:,2)-xd(:,3)).*G32));
a6=((xd(:,2).*G21)./((xd(:,2).*G11)+(xd(:,3).*G21)+((1-xd(:,2)-xd(:,3)).*G31))).*(tow21-(((xd(:,2).*tow11.*G11)+(xd(:,3).*tow21.*G21)+((1-xd(:,2)-xd(:,3)).*tow31.*G31))./((xd(:,2).*G11)+(xd(:,3).*G21)+((1-xd(:,2)-xd(:,3)).*G31))));
a7=((xd(:,3).*G22)./((xd(:,2).*G12)+(xd(:,3).*G22)+((1-xd(:,2)-xd(:,3)).*G32))).*(tow22-(((xd(:,2).*tow12.*G12)+(xd(:,3).*tow22.*G22)+((1-xd(:,2)-xd(:,3)).*tow32.*G32))./((xd(:,2).*G12)+(xd(:,3).*G22)+((1-xd(:,2)-xd(:,3)).*G32))));
a8=(((1-xd(:,2)-xd(:,3)).*G23)./((xd(:,2).*G13)+(xd(:,3).*G23)+((1-xd(:,2)-xd(:,3)).*G33))).*(tow23-(((xd(:,2).*tow13.*G13)+(xd(:,3).*tow23.*G23)+((1-xd(:,2)-xd(:,3)).*tow33.*G33))./((xd(:,2).*G13)+(xd(:,3).*G23)+((1-xd(:,2)-xd(:,3)).*G33))));
gamma_one=exp(a1+a2+a3+a4);
gamma_two=exp(a5+a6+a7+a8);
yd=(xd(:,2).*gamma_one.*xd(:,4))+(xd(:,3).*gamma_two.*xd(:,5));
end
please help me out of this error:'You can not subscript a table using only one subscript. Table subscripting requires both row and variable subscripts.'
Thank you in advance.

请先登录，再回答此问题。

采纳的回答

Walter Roberson
Walter Roberson 2020-1-13
[a{K}, resnorm{K}]= lsqcurvefit( @(a,xd) curvefit_multiobjective_two(a, xd{K}), a0, xd{K} , yd{K}, lb, ub, options);
The xd inside the @ function definition is not the same xd as after the a0 in the call. The one after the a0 is a table object. When you access a table object with {} indexing, you must use two subscripts, such xd{K,:}
  3 个评论
显示 1更早的评论
Ashish Kundaliya
Ashish Kundaliya 2020-1-14
Thank you, sir for this helpful answer. Now this error has been resolved but my main Aim is to Data fit into This NRTL thermodynamic model for ternary mixture. While solving this above code i have to give some intial guess(Obvious) for getting that Constant (a Value). but i am getting trouble into giving its initial guess, as what initial guess will give me best fit. because till now i have tried number of intial guess and got the result but it was not upto the mark. so, is there any technique for Data fitting where that method will take initial guess on its own and give me best fit..???
Pl. note that constant a is a set of matrix which consist of 12 constant value in it. where principle diagonal value of matrix is Zero and so this is two sets of 3*3 matrix.

请先登录，再进行评论。

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Thermodynamics and Heat Transfer 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by