Error using vertcat Dimensions of arrays being concatenated are not consistent.

Question

Dursman Mchabe 2018-8-15

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/414912-error-using-vertcat-dimensions-of-arrays-being-concatenated-are-not-consistent

评论： Dursman Mchabe 2018-8-15

采纳的回答： Jan

simultaneousEquations1.m

High everyone, I am unsuccessful in getting consistent dimensions for t and y in this code:

https://www.dropbox.com/s/7sz6gli891k0u4l/simultaneousEquations1.m?dl=0

What can I do?

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Dennis 2018-8-15

在 MATLAB Online 中打开

On the bright side: i found out which lines caused the error, however i have no clue why. My fix seems to be voodoo aswell.....

function yp = revisedModelode(t,y)
yp=[(1/1.5e-6)*((1.67e-5*6.51e-2)-((1.67e-5)*(y(1))))-(((y(1))*(8.314)*(323.15)-(149*(y(8))))/((1/4.14e-6)+(149/((1+(1.39e-9*(y(9)))/(2.89e-9*(y(3))))*8.4e-4))))
1/1.5e-6*(-1.67e-5*(y(2)))-(9.6e-4*(1+(1.39e-9*(y(9)))/(3.53e-9*(y(4))))*((y(2))*8.314*323.15/5.15e3-(y(10))))
(((y(1))*8.314*323.15-149*(y(8)))/(1/4.14e-6)+(149/((1+(1.39e-9*(y(9)))/(2.89e-9*(y(3))))*8.4e-4))-(0.162*exp(5153/323.15)*((((y(9))*(y(11)))/1.1e-7)- 1)*(10/(((y(9))*(y(11)))/1.1e-7))))
(9.6e-4*(1+ (1.39e-9*(y(9)))/(3.53e-9*(y(4))))*((y(2))* 8.314*323.15/5.15e3 - (y(10))))-(-8.825e-3*12.54*100.0869*(y(6))*(y(12))*(1-(0.84*(y(12)))/(1+0.84*(y(12)))))
(-8.825e-3*12.54*100.0869*(y(6))*(y(12))*(1-(0.84*(y(12)))/(1+0.84*(y(12)))))- (0*162*exp(-5153/323.15)*((((y(9))*(y(11)))/1.1e-7)-1*(10/(((y(9))*(y(11)))/1.1e-7))))
-(y(6))*(-8.825e-3*12.54*100.0869*(y(6))*(y(12)) *(1-(0.84*(y(12)))/(1+0.84*(y(12)))))*100.0869/2703
(-8.825e-3*12.54*100.0869*(y(6))*(y(12)) *(1- (0.84*(y(12)))/(1+0.84*(y(12)))))*258.30/2540
(y(12))+2*(y(9))-(((y(3))*6.24*(y(12)))/((y(12))^2 + 6.24*(y(12))+ 6.24*5.68e-5))-2*(((y(3))*6.24*5.68e-5)/((y(12))^2 + 6.24*(y(12))+6.24*5.68e-5))-(((y(4))*1.7e-3*(y(12)))/((y(12))^2 + 1.7e-3*(y(12)) + 1.7e-3*6.55e-8))-2*(((y(4))*1.7e-3*6.55e-8)/((y(12))^2 + 1.7e-3*(y(12))+ 1.7e-3*6.55e-8))- 5.3e-8/(y(12))
%1.7e-3 -(y(12))*(y(14))/(y(10))
%6.55e-8 -(y(12))*(y(15))/(y(14))
1.7e-3 - y(12)*y(14)/y(10)
6.55e-8 - y(12)*y(15)/y(14)
6.24-(y(12))*(y(13))/(y(8))
5.68e-5-(y(12))*(y(11))/(y(13))
5.3e-8 - (y(12))*(y(16))
(y(3))-(y(8))-(y(13))-(y(11)) 
(y(4))-(y(10))-(y(14))-(y(15)) 
(y(5))-(y(10))-(y(14))-(y(15))];

Stephen23 2018-8-15

编辑：Stephen23 2018-8-15

"however i have no clue why"

https://www.mathworks.com/help/matlab/matlab_prog/case-and-space-sensitivity.html

No Voodoo required, just reading the MATLAB documentation.

Dursman Mchabe 2018-8-15

Thanks a lot for the comments, I will improve my spacing, and try to run the code again.

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Answer 1

Jan 2018-8-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/414912-error-using-vertcat-dimensions-of-arrays-being-concatenated-are-not-consistent#answer_332830

在 MATLAB Online 中打开

I prefer spaces around each operator and keeping the parentheses only, where they improve the readability. Compare:

1.7e-3 -(y(12))*(y(14))/(y(10))
6.55e-8 -(y(12))*(y(15))/(y(14))
6.24-(y(12))*(y(13))/(y(8))
5.68e-5-(y(12))*(y(11))/(y(13))
5.3e-8 - (y(12))*(y(16))
(y(3))-(y(8))-(y(13))-(y(11)) 
(y(4))-(y(10))-(y(14))-(y(15)) 
(y(5))-(y(10))-(y(14))-(y(15))];

with

1.7e-3  - y(12) * y(14)) / y(10); ...
6.55e-8 - y(12) * y(15)) / y(14); ...
6.24    - y(12) * y(13)  / y(8); ...
5.68e-5 - y(12) * y(11)  / y(13); ...
5.3e-8  - y(12) * y(16); ...
y(3) - y(8)  - y(13) - y(11); ...
y(4) - y(10) - y(14) - y(15); ...
y(5) - y(10) - y(14) - y(15)];

Consider Stephen's advice to avoid ambiguities in the code. The less readable the code is, the harder is it to debug. Splitting the calculations into separate lines is a good idea.

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Dursman Mchabe 2018-8-15

Thanks a lot. I will do exactly that.

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Answer 2

Stephen23 2018-8-15

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/414912-error-using-vertcat-dimensions-of-arrays-being-concatenated-are-not-consistent#answer_332826

编辑：Stephen23 2018-8-15

在 MATLAB Online 中打开

The problem is how you have written your vector with random space characters. For example this:

1.7e-3 -(y(12))*(y(14))/(y(10))...
      ^^ ouch!!!

MATLAB will interpret X -Y as equivalent to X,-Y. Why is this a problem? Because you have lots of lines with no spaces (giving only one column) and then some lines with spaces (giving multiple columns). Clearly these cannot be vertically concatenated together in any sensible way:

yp = [...
     A-B-C   % no spaces -> one column
     A -B-C  % space -> two columns
     ...]

This is clearly documented:

https://www.mathworks.com/help/matlab/matlab_prog/case-and-space-sensitivity.html

I recommend that you use consistent spacing, either one of these will work:

A - B
A-B

but you should NOT try to mix the two! I recommend that when concatenating like that, you should use explicit commas and semi-colons to delimit all elements of the matrix, e.g.:

yp = [...
     A+B;
     C-D-E;
     F+G;
     ...]

This makes it clear what your intent was, whereas A -B-C is totally ambiguous: is it a mistake, or is that gap intentional? Using commas and semi-colons makes the code intent much clearer. Clearer code is easier to understand, and is much less buggy.

But in this case, because your calculations are quite verbose, I think it would be clearer to use indexing, like this:

yp = y;
yp(1) = A+B;
yp(2) = C-D-E;
yp(3) = F+G;
...

This has the major advantage that if there is any syntax error it will indicate the particular line on which the error occurs, making your debugging much simpler.