Is there any build in function to perform polynomials multiplication?

1 view (last 30 days)
Abdulatif Alabdulatif
Abdulatif Alabdulatif on 9 Nov 2014
Commented: Abdulatif Alabdulatif on 10 Nov 2014
Hi,
I try to find a build in function that satisfy the following:
(x1,y1) , (x2,y2)
result in:
( 0 , (x1*x2) , (x1*y2) + (y1*x2) , (y1*y2) )
I did it using while loop but it is useless! it take to long time : (
Thank you
  2 Comments
Jan
Jan on 9 Nov 2014
Claiming that the loop takes too long is not useful, when you do not post the code. Perhaps you did only forget to pre-allocate the result. In addition it is not clear if "x1" and "x2" are two variables with inconvenient names or the elements of a vector. The less the readers have to guess, the more useful will be the answers.
Abdulatif Alabdulatif
Abdulatif Alabdulatif on 10 Nov 2014
This is the code:
vector1 = [232,334];
vector2 = [121,523];
M = sym(1000000000000);
A1 = length(vector1);
A2 = length(vector2);
A3 = length(vector1)+ length(vector2);
result = sym(zeros(1,A3));
mult=sym(0);
index=0;
% Set the first value of result vector to (0)
result(1,i) = 0;
% perform polynomials multiplication
i=1;
j=1;
while i < A1+1
while j < A2+1
index = i + j;
mult = sym((vector1(1,i) * vector2(1,j)));
mult = sym(rem(mult,M));
result(1,index) = result(1,index) + mult;
j=j+1;
end
j=1;
i = i+1;
end
produce:
result = [0, x1, x2, x3], where x1,x2 and x3 are variables.
As I implement clustering algorithm, I have to run this code around 4000 times which takes long time.
Sorry for inconvenient explanation!

Sign in to comment.

Sign in to answer this question.

Accepted Answer

Rick Rosson
Rick Rosson on 9 Nov 2014
u = [ x1 ; y1 ];
v = [ x2 ; y2 ];
z = conv(u,v);

More Answers (0)

Categories

Find more on Polynomials in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!