Calling for a matrix value

I need to call for values for values from teh matix Qsol every hour of the day but when i try it it gives me an error "??? Subscript indices must either be real positive integers or logicals."

t = 0:1:24

Qsol = [0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 32,71,5,5,9; 57,472,38,38,119; 83,651,68,63,286; 87,679,107,82,454; 97, 606,209,97,595; 107,457,318,107,704; 114,252,394,114,772; 116,126,420,126,795; 114,114,394,252,772; 107,107,318,457,704; 97,97,209,606,595; 87,82,107,679,454; 83,63,68,651,286; 57,38,38,472,119; 32,5,5,71,9; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0];

-Qsol(t,1)

Any help will be most appreciated :)

Thanks

Answer 1

[Fangjun Jiang]

t can not contain 0.

Maybe t should be 1:24?

You can use this syntax to get the first column of Qsol

Qsol(:,1)

[Hussein]

Thanks a lot :)

[Hussein]

I got another question, I am building a program that solves 22 equations for each hour of the day, and each hour of the day some values change in the equations until now i have come to this,

Tomax = 37;

Tomin = 25;

hi = 4.25;

ho = 2.85;

hr = 1.5;

Ks = 0.72;

Kc = 1;

Kg = 0.72;

Xs = 0.0015;

Xc = 0.2;

Xg = 0.003;

Cs = Ks/Xs;

Cc = Kc/Xc;

Cg = Kg/Xg;

Cp = 1;

Kair = 0.0257;

Dair = 1.2;

Ar = 80;

An = 20;

As = 20;

Aw = 25;

Ae = 25;

Af = 80;

Ws = 3;

Ww = 1.5;

We = 1.5;

ACH = 0.5;

V = 200;

t = 1:24

Qgen = [140,140,140,140,140,140,140,140,2140,70,70,70,70,70,70,70,70,70,140,2140,140,140,140,140];

To = (Tomax+Tomin)/2 + (Tomax-Tomin)/2*sin(3.14/12*(t-9));

Tsky = To - 5;

Qsol = [0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 32,71,5,5,9;

57,472,38,38,119; 83,651,68,63,286; 87,679,107,82,454; 97, 606,209,97,595;

107,457,318,107,704; 114,252,394,114,772; 116,126,420,126,795; 114,114,394,252,772;

107,107,318,457,704; 97,97,209,606,595; 87,82,107,679,454; 83,63,68,651,286;

57,38,38,472,119; 32,5,5,71,9; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0; 0,0,0,0,0]

Coef = [-hr-ho-Cs,Cs,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

Cs,-Cs-Cc,Cc,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

0,Cc,-Cg-Cc,Cg,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

0,0,Cg,-Cg-hi,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,hi,0;

0,0,0,0,-hr-ho-Cs,Cs,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,Cs,-Cs-Cc,Cc,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,0,Cc,-Cg-Cc,Cg,0,0,0,0,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,0,0,Cg,-Cg-hi,0,0,0,0,0,0,0,0,0,0,0,0,hi,0;

0,0,0,0,0,0,0,0,-hr-ho-Cs,Cs,0,0,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,Cs,-Cs-Cc,Cc,0,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,0,Cc,-Cg-Cc,Cg,0,0,0,0,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,0,0,Cg,-Cg-hi,0,0,0,0,0,0,0,0,hi,0;

0,0,0,0,0,0,0,0,0,0,0,0,-hr-ho-Cs,Cs,0,0,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,0,0,0,0,Cs,-Cs-Cc,Cc,0,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,Cc,-Cg-Cc,Cg,0,0,0,0,0,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,Cg,-Cg-hi,0,0,0,0,hi,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-hr-ho-Cc,Cc,0,0,0,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,Cc,-Cc-Cg,Cg,0,0,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,Cg,-Cg-hi,0,hi,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-Af*(hi+hr),Af*(hi+hr),0;

0,0,0,hi,0,0,0,hi,0,0,0,hi,0,0,0,hi,0,0,hi,hi,-6*hi,0;

0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,ACH*V*Dair*Cp,1]

Cons = [-Qsol(t,1) - Tsky*hr - To*ho;0;0;0;

-Qsol(t,2) - Tsky*hr - To*ho;0;0;0;

-Qsol(t,3) - Tsky*hr - To*ho;0;0;0;

-Qsol(t,4) - Tsky*hr - To*ho;0;0;0;

-Qsol(t,5) - Tsky*hr - To*ho;0;0;

-Ws*Qsol(t,3) - We*Qsol(t,2) - Ww*Qsol(t,4);

-Qgen(t) - Qinf;

ACH*V*Dair*Cp*To]

When i run it it gives me Error using ==> minus

Matrix dimensions must agree.

Can you help me ?

Thanks

[Fangjun Jiang]

In the last statement, Qsol(t,1) is a 24 by 1 vector, but Tsky*hr is a 1 by 24 vector. That causes the problem. If you save the above code in a script and run it, it will tell you which line cause the problem. Also, you can set a break point and run the code line by line. In the M-editor, click menu Debug.

[Hussein]

Thanks :) I am going to try it right away and how do i switch the Qsol(t,1) from 24 by 1 to 1 by 24

Thanks :)

[Fangjun Jiang]

Use function transpose(), in many case, use the single quote symbol,'

A=1:5; B=A';