MATLAB: Attribute to an array of symbolic variables an array with their values

symbolicSymbolic Math Toolbox

HI all

Is there a trick to do this in MATLAB ?

[R1 R2 R3 VA VB VG]=[8 2 4 12 -6 0]

I want to assign to all sym variables the values on right

Best Answer

 V = num2cell([8 2 4 12 -6 0]);
 [R1 R2 R3 VA VB VG] = deal(V{:});

This does not have anything to do with the symbolic toolbox ? Or are you wanting to subs() like that? If so then

subs(TheExpression, [R1 R2 R3 VA VB VG], [8 2 4 12 -6 0])

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MATLAB: How to modify this code for combining matrices

[m,n] = size(A);
Y1 = reshape(permute(cat(3,A,circshift(A,[0 -1])),[3,2,1]),2,[]); % 
Y2 = flip(Y1,1);
Bp = permute(B,[2,3,1]);
X = reshape(any([all(bsxfun(@eq,Y1,Bp));all(bsxfun(@eq,Y2,Bp))]),m*n,[])';
C = reshape(max(bsxfun(@times,X,(1:size(B,1))')),[],m)'-1;

MATLAB: Check for missing argument or incorrect argument data type in call to function ‘solve’. Error in LinearProject (line 35) I=solve(eq1, eq2, eq3, eq4); The program just print the first 4 i’s. The program should print 44 i’s. How to solve

syms i1 i2 i3 i4 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11;

i1 i2 i3 i4 start out as symbolic

    eq1 = 3-V(j,1)*(i1)-V(j,2)*(i1-i4)-V(j,3)*(i1+i2)-V(j,4)*i1==0;
    eq2 = 3-V(j,4)*(i2 + i3)-V(j,8)*(i2+i4)-V(j,3)*(i2+i1)-V(j,5)*(i2)-V(j,6)*(i2+i3)== 0;
    eq3 = 3-V(j,7)*(i2+i3)-V(j,10)*(i3-i4)-V(j,6)*(i3+i2)-V(j,9)*i3==0;
    eq4 = V(j,2)*(i4-i1)+V(j,8)*(i2+i4)+V(j,10)*(i4-i3)+V(j,11)*i4==0;

and get used in those equations, so those start out as symbolic equations

    i1=0;
    i2=0;
    i3=0;
    i4=0;

Now they are assigned numeric, so they are no longer symbolic. So when you loop back to eq1 etc, those become expressions of numeric values == numeric values, which gives a logical result, not symbolic.

Best Answer

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MATLAB: How to modify this code for combining matrices

MATLAB: Check for missing argument or incorrect argument data type in call to function ‘solve’. Error in LinearProject (line 35) I=solve(eq1, eq2, eq3, eq4); The program just print the first 4 i’s. The program should print 44 i’s. How to solve

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