Forums

freq. components of a matrix

Started by kianogo December 15, 2003
Hi,

I want to find fractions of vertical and horizontal frequencies of
"a" by the following commands:
a=
1 4 7 10
2 5 8 11
3 6 9 12
13 14 15 16

pt(a); % fft of the matrix "a" in row-direction
aT=a.';
qt(aT); % fft of "a" in column-direction
K=sqrt(p.^2+q.^2); % total frequency
u=j*p/K; % freq. of rows
v=j*q/K; % freq. of columns, where j=sqrt(-1)

Here Matlab returnes inf-values for u and v! It also produce an error
message I don't understand:
(Warning: Matrix is singular to working precision.)
(Type "warning off MATLAB:singularMatrix" to suppress this warning.)

Anyone can please tell me why I get u and v to be inf-values? or how
I can get the u and v without this error in matlab?

thanx a lot



chek out fft2

--- kianogo <> wrote:
> Hi,
>
> I want to find fractions of vertical and horizontal frequencies of
> "a" by the following commands:
> a=
> 1 4 7 10
> 2 5 8 11
> 3 6 9 12
> 13 14 15 16
>
> pt(a); % fft of the matrix "a" in row-direction
> aT=a.';
> qt(aT); % fft of "a" in column-direction
> K=sqrt(p.^2+q.^2); % total frequency
> u=j*p/K; % freq. of rows
> v=j*q/K; % freq. of columns, where j=sqrt(-1)
>
> Here Matlab returnes inf-values for u and v! It also produce an
> error
> message I don't understand:
> (Warning: Matrix is singular to working precision.)
> (Type "warning off MATLAB:singularMatrix" to suppress this
> warning.)
>
> Anyone can please tell me why I get u and v to be inf-values? or
> how
> I can get the u and v without this error in matlab?
>
> thanx a lot >


=====
-
Its not life that weighs us down,
Its how we carry it. __________________________________