how to use command"matlabFunction" in loop and handle function in loop

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tony kevine
tony kevine 2015-4-17
评论： Star Strider 2015-4-20
syms x y
rr=[x^2+y^2,x^2+1,y^2+2,3*x^3;
y^7+2,x^2+y,x^4+y^7,2]
for i=1:8
f(i)=matlabFunction(rr(i))
ma(i)=dblquad(f(i),-1,1,-1,1)
end
Can anyone help!! i really need help!! Above is my code!! my aim is to double integral(dblquad) the code have error when i run it .can any help me to modify it!! rr is my assumption.ecactly rr is big so i use a small matrix to replace
  2 个评论
Star Strider
Star Strider 2015-4-20
Go to the MATLAB Index and search for the function. The approximate release when it first appeared is at the end of the documentation page for it. That is new with the documentation for the R2015a release that is the current online documentation.

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采纳的回答

Star Strider
Star Strider 2015-4-17
It’s best not to bother with the numeric integrations and just keep it symbolic:
syms x y
rr=[x^2+y^2,x^2+1,y^2+2,3*x^3;
y^7+2,x^2+y,x^4+y^7,2]
ma_x = int(rr, x, -1, 1);
ma = int(ma_x, y, -1, 1)
produces:
ma =
[ 8/3, 16/3, 28/3, 0]
[ 8, 4/3, 4/5, 8]
  2 个评论
tony kevine
tony kevine 2015-4-17
dear Star Strider.
above rr is sample matrix ,exactly my matrix is so big and it need to numerically method to solve it.thanks you answer my issue
Star Strider
Star Strider 2015-4-17
My pleasure.
Have you tried this on your much larger matrix?
I attempted a number of numerical integration routines (including those available in R2015a, such as integral with the 'ArrayValued',1 option) and I could not get it to run without throwing an error.
The only other option I can think of is to integrate each element of your matrix separately, creating a separate anonymous function for each element.

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更多回答（1 个）

Sean de Wolski
Sean de Wolski 2015-4-17
Use cells to store the function handles
syms x y
rr=[x^2+y^2,x^2+1,y^2+2,3*x^3;
y^7+2,x^2+y,x^4+y^7,2]
f = cell(8,1)
for i=1:8
f{i}=matlabFunction(rr(i))
ma(i)=dblquad(f{i},-1,1,-1,1)
end
This won't fix the fact that your functions need different inputs so you'll need to figure that out.
  1 个评论
tony kevine
tony kevine 2015-4-17
hi,why need more inputs.actualy my real matrix is so big .above is my assumption i just ran your code,and it occur error.can you explain again(i am asian so please use some simple words)

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