Can I assign a variable to a number in a matrix from another matrix?
조회 수: 3 (최근 30일)
이전 댓글 표시
Using the matrix that comes from eig(), I would like to assign individual values in it to 3 separate variables, and then plug those into a separate matrix. However, I get an error. How do I do this?
E = eig(A)
E(1,1) = w1;
E(2,1) = w2;
E(3,1) = w3;
ans = [m1*w1^2 0 0;
0 m2*w2^2 0;
0 0 m3*w3^2 0]
Unrecognized function or variable 'w1'.
Error in eigen (line 23)
E(1,1) = w1;
댓글 수: 0
채택된 답변
Walter Roberson
2021년 3월 2일
A = magic(7)
E = eig(A)
w1 = E(1,1)
w2 = E(2,1)
w3 = E(3,1)
m1 = 3; m2 = 11; m3 = -7;
output = [
m1*w1^2 0 0;
0 m2*w2^2 0;
0 0 m3*w3^2]
댓글 수: 6
Walter Roberson
2021년 3월 11일
syms k
A = [2*k -k -k;
-k 2*k -k;
-k -k 2*k];
E = eig(A)
If you are expecting 2.449 then your k would have to be roughly 0.816
추가 답변 (1개)
Steven Lord
2021년 3월 2일
There's a way to do this without creating 2*n individual variables.
A = magic(7);
E = eig(A);
w = E(1:3);
m = [3; 11; -7];
output1 = diag(m.*(w.^2))
w1 = E(1,1);
w2 = E(2,1);
w3 = E(3,1);
m1 = 3; m2 = 11; m3 = -7;
output2 = [ m1*w1^2 0 0;
0 m2*w2^2 0;
0 0 m3*w3^2]
You can compare output1 and output2. The first block of code scales to larger matrices with more eigenvalues.
댓글 수: 0
참고 항목
카테고리
Help Center 및 File Exchange에서 Creating and Concatenating Matrices에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!