Multiplication of complex matrices
91 views (last 30 days)
Show older comments
Vage Karakhanyan
on 24 Oct 2019
Commented: Vage Karakhanyan
on 24 Oct 2019
I have noticed that when I multiply 2 matrices with complex elements A*B, Matlab takes the complex conjugate of matrix B and multiplies A to conj(B).
For example I have a complex vector a = [2+0.3i, 6+0.2i], so the multiplication a*(a') gives 40.13 which is not correct. However, when I want to calculate square of the norm of vector 'a' norm_square = a*conj(a)' I get complex number which is a sum of squares of the vector components.
My question is: is it a bug or I just dont get the way matlab works with complex numbers?
1 Comment
James Tursa
on 24 Oct 2019
"when I multiply 2 matrices with complex elements A*B, Matlab takes the complex conjugate of matrix B and multiplies A to conj(B)"
No, it doesn't.
Accepted Answer
James Tursa
on 24 Oct 2019
Edited: James Tursa
on 24 Oct 2019
There are two different operators:
' is the complex conjugate transpose
.' is the straight transpose (no complex conjugate), notice the dot
Use the operator that is appropriate for your application. If you only want the transpose with no conjugation, then use the dot version .'
Side Note: Related to this, the dot( ) function effectively uses the ' operation internally ... i.e., it does a complex conjugate of the first argument.
More Answers (0)
See Also
Categories
Find more on Operators and Elementary Operations in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!