calling a callback function from script

Question

vishnuvardhan naidu tanga 2020-2-7

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https://ww2.mathworks.cn/matlabcentral/answers/504196-calling-a-callback-function-from-script

编辑： JESUS DAVID ARIZA ROYETH 2020-2-7

hello everyone,

I am trying to calculate the steam table data using the XSteam.m script. I have written a callback loop to calculate the density of the steam at perticular temperature and pressure values. the function is as follows.

where a is the final pressure

When i am trying to run the script it gives an error as

Error using zeros

Maximum variable size allowed by the program is exceeded.

Error in Untitled2 (line 5)

y = zeros(1:((a-1)/b));

Please check the script and help me with it.

With regards.

a = 10;
b = 0.01;
T = 200;
y = zeros(1:((a-1)/b));
L = length(y);
for i = 0:L
    p(i)= 1+b*i;
    y(i) =XSteam('rho_pT',i,T);
end

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Stephen23 2020-2-7

在 MATLAB Online 中打开

This code

zeros(1:((a-1)/b))

defines an array with size

zeros(1,2,3,4,5,6,7,8,9,10,11,...,900)

which would require so much memory that it can't even be calculated using double numeric class. Impressive, but unlikely to be very useful. Perhaps you meant:

zeros(1,((a-1)/b));
%      ^ comma

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Answer 1

JESUS DAVID ARIZA ROYETH 2020-2-7

0
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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/504196-calling-a-callback-function-from-script#answer_414318

编辑：JESUS DAVID ARIZA ROYETH 2020-2-7

在 MATLAB Online 中打开

is y = zeros(1,((a-1)/b)); you have ":" instead of a ","

a = 10;
b = 0.01;
T = 200;
y = zeros(1,((a-1)/b));
L = length(y);
for i = 1:L
    p(i)= 1+b*i;
    y(i) =XSteam('rho_pT',i,T);
end

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Steven Lord 2020-2-7

在 MATLAB Online 中打开

There's no such thing as element 0 in an array in MATLAB. The first element of p is p(1) not p(0).

In this case there's no need to create p inside the for loop.

p = 1 + b*(0:L);

I don't know whether your XSteam function can accept a vector of values as its second input. If it can (and returns a vector the same size as that second input, where each element of the output is the result of operating on the corresponding element of that second input) you could eliminate the loop altogether.

y = XSteam('rho_pT', 0:L, T);

vishnuvardhan naidu tanga 2020-2-7