Multiple Vector

Hello Redgurl,

Matlab is finicky about syntax and so may gag at the lack of whitespace following the semicolons in your vectors. You may also wish to remove the trailing semicolon in vector Vb. Also try writing Va and Vb as row vectors (if for no other reason than that they're a bit easier on the eye).

Hence:

Va = [ 0 3 3 0 ]
Vb = [ 3 3 0 0 ]

Create a result vector having the same size as our operand vectors. N is the number of elements in Va (Vb would do just as well since they're the same size).

N = max(size(Va));
V1 = zeros(N,1);

For each pair of elements Va(k) and Vb(k), compute a result and place the result into vector V1 at element k.

for k = 1:N,
V1(k) = 7*Va(k) + 8*Vb(k);
end

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Now let's create a simple function, 'foo', that does the same thing (feel free to call 'foo' something else). Also note that comment delimiters '%' are not present. CR4's editor doesn't preserve the user's format, and so we would probably find our delimiters all over the map.

function [X] = foo(A,B)

N = max(size(A));
X = zeros(N);

for i = 1:N,
X(i) = 7*Va(i) + 8*Vb(i);
end

End function foo(A,B)

------------------------------------------------

Example of using function foo(A,B):

Va = [ 0 3 3 0 ]
Vb = [ 3 3 0 0 ]

Z = foo(Va,Vb);

Hope this helps.

-e

Erratum:

In function foo(A,B) the line:

X(i) = 7*Va(i) + 8*Vb(i);

should read:

X(i) = 7*A(i) + 8*B(i);

Matlab understands vectors so most of the time one doesn't need to use the "for..." construct. The following sequence will do it:

Va = [0 3 3 0];

Vb = [3 3 0 0];

V1 = 8*Va + 7*Vb;

% If you prefer column vectors instead of row:

Vout = V1';

% You may be aware of the following:

Va*Vb' % yields:

answer 9

% while

Va.*Vb % yields:

answer [0 9 0 0]

% once again, one doesn't need the "for..."

% cheers

Thanks, Daniel. This is good to know.