MATLAB: How Can I put some numbers in a sym and sum its cells

integration

I have the matrix [A]= [ a*(x^2)+y , b(y^3)+x ; d*(x^2)*y , c*y ].

and I have the matrix [B]=[1 2;3 4] which the first column of [B] is x and the socond culomn Of [B] is y .

I want to put x=1 and y=2 then x=3 and y=4 and sum A11. then do it for other cells.

Best Answer

syms a b c d 
B = [ 1 2 ; 3 4] ; 
x = reshape(B(:,1),1,1,[]); 
y = reshape(B(:,2),1,1,[]); 
A = [ a*(x.^2)+y , b*(y.^3)+x ; d*(x.^2).*y , c*y ] ; 
a = arrayfun(@(z) sum(sum(A(:,:,z))), 1:size(A,3),'un',0);
celldisp(a)

Related Solutions

MATLAB: How can i use a cell array in the symbolic variables

Wanted = num2cell(symvar(B))

edit: After your comment.

>> syms a b c d x y z
>> A = [ a*(x^2) , b*(y^3) ; d*(x^2)*y , c ]
 
A =
 
[   a*x^2, b*y^3]
[ d*x^2*y,     c]
 
>> B = repelem({A},3,1)
B =
  3×1 cell array
    {2×2 sym}
    {2×2 sym}
    {2×2 sym}
>>

MATLAB: How to subs 2 symbolic vectors in 1 comand

You defined ‘Z’ to require 4 different arguments, so the substitution has to match them, either using subs or using ‘Z’ as a function:

syms a b c d
X=[a,b]; Y=[c,d];
Z=[X;Y];
X0=[1,2]; Y0=[3,4];
Zs = subs(Z,{a,b,c,d},{X0(1),X0(2),Y0(1),Y0(2)})
syms a b c d
X=[a,b]; Y=[c,d];
Z(X,Y)=[X;Y];
X0=[1,2]; Y0=[3,4];
Zs = Z(X0(1),X0(2),Y0(1),Y0(2))

However if you defined ‘Z’ differently, these would work:

syms a b c d
X=a; Y=c;
Z=[X;Y];
X0=[1,2]; Y0=[3,4];
Zs = subs(Z,{X,Y},{X0,Y0})
syms a b c d
X=a; Y=c;
Z(X,Y)=[X;Y];
X0=[1,2]; Y0=[3,4];
Zs = Z(X0,Y0)

Best Answer

Related Solutions

MATLAB: How can i use a cell array in the symbolic variables

MATLAB: How to subs 2 symbolic vectors in 1 comand

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