Set initial value in Matlab Function block

2014 4 17
2 个回答
更新时间：2018 12 4
2 次查看（30 天）

0 个投票

How can I set the initial value for UP? UPI is my initial value input to the block. How can I make sure UP will accepts thhs value only once (start of the simulation)? Thanks
funciton UP=[UPI]
*UP=UPI;
%#close safety_relieve_valve
SRV=0;
if (UP>UL)
Val=0;
UP=RD;
else
Val=1;
UP=RU;
end
if (UP<LL) & (Val==0)
UP=RD+0.1;
disp(UP);
Val=1;
elseif (UP>=LL) & (Val==1)
UP=UP+0.1;
end*

5 个评论
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William
William 2014-4-17
The issue of the if statement is resolved. Is there any block to extract a single element from the vector (entered from "From Workspace" block) to set as the input to the ML Fctn block?
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
What do you mean? the same single element each iteration, or the first, then the second, and so on ?
William
William 2014-4-17
I am required to enter input interactively so I used the "From Workspace" block. This block can only input with vector instead of scalar value. I would like to extract a single element from this vector then.
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
have you tried Ports and Data Manager?
William
William 2014-4-17
The input is set as Inherit: same as Simulink. I kept getting error "Expecting scalr...." I changed the type to "double" but no avail.

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回答（2 个）

Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
编辑：Azzi Abdelmalek 2014-4-17

1 个投票

You can use persistent declaration
function UP=fcn(UPI)
persistent UPI1
if isempty(UPI1)
UP=UPI
else
UP=UPI1
end
%your code
UPI1=UP;

11 个评论
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William
William 2014-4-17
What is UP1 & UPI1?
Thanks.
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
UP1 does not exist (The answer was edited) UPI1 is an intermediate variable
William
William 2014-4-17
Referring to my code above, my if (UP>UL) is not executed. I checked the value of UP & it is greater than UL during the simulation. Any suggestion?
Thanks.
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
编辑：Azzi Abdelmalek 2014-4-17
What UL and other variables represent? If they are constants from workspace, use Ports and Data Manager
William
William 2014-4-17
UL, LL & UPI are all constants. I tried different opitons with Port and Data manager but the "if (UP>UL) is still not executed. BTW, does size matter (it is currently set at -1)? Thanks.
William
William 2014-4-17
UL equals to 18 & its sapling size is inf.
Azzi Abdelmalek
Azzi Abdelmalek 2014-4-17
its sapling size is inf ? what is that ?
William
William 2014-4-17
I meant sampling time in the property box of constant block.
William
William 2014-4-17
Instead of using the 'elseif' statement, I created another 'if' statement & it worked. But there are some other issues I would like to resolve. I will post it later. Thanks again.
William
William 2014-5-19
编辑：Azzi Abdelmalek 2014-5-19
function UP = UPC(t,LL,u1,u2,u3,u4,u5,u6,u7,u8)
%#codegen
persistent LLI
if isempty(LLI)
UP=LL;
else
UP=LLI;
end
My code
LLI=UP;
Azzi, I kept getting the error message "LLI is not defined..." when I attempted to run the simulation. "LL" is my IC for UP. Any idea? Thanks.

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Danilo Teran
Danilo Teran 2018-12-4

1 个投票

Hi
I have a similar problem, could you find a real solution.
Best regards?

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提问:

William
William
2014-4-17

回答：

Danilo Teran
Danilo Teran
2018-12-4

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