Thread Subject: randn usage error

Hello all,

This is my first post so if its in an inappropriate section, my apologies.
 So this is the situation, I'm working on my postgrad project which involves locating a cell phone and I use Time Difference of Arrival with wavelet denoising filtering. I came across someone else's work which is similar to mine but in a diff technology. So I took up to study his code to get an idea of what I'm supposed to do.

In this test program.
this line is not working

randn('state', 2*(i+j));
        noi1_real=sqrt(pow/(2*oran))*randn(1,1024);

And the error is
??? Error using ==> randn
State must be a double scalar or the output of RANDN('state').

Error in ==> tez5 at 36
        randn('state', t);

Can anyone throw some light on what I'm supposed to do.

Thanks in advance

Cheers
Vi

"Vijayalayan T.R." <xcitingindian@yahoo.com> wrote in message <hcs392$4ve$1@fred.mathworks.com>...
> Hello all,
>
> This is my first post so if its in an inappropriate section, my apologies.
> So this is the situation, I'm working on my postgrad project which involves locating a cell phone and I use Time Difference of Arrival with wavelet denoising filtering. I came across someone else's work which is similar to mine but in a diff technology. So I took up to study his code to get an idea of what I'm supposed to do.
>
> In this test program.
> this line is not working
>
> randn('state', 2*(i+j));
> noi1_real=sqrt(pow/(2*oran))*randn(1,1024);
>
> And the error is
> ??? Error using ==> randn
> State must be a double scalar or the output of RANDN('state').
>
> Error in ==> tez5 at 36
> randn('state', t);
>
> Can anyone throw some light on what I'm supposed to do.
>
> Thanks in advance
>
> Cheers
> Vi

Hi, what are i and j equal to? If you don't assign these in your code, then by default they will be the complex number 0 + 1.0000i and you will get the above error.
Wayne

Vijayalayan T.R. wrote:

> randn('state', 2*(i+j));

> And the error is
> ??? Error using ==> randn
> State must be a double scalar or the output of RANDN('state').

As Wayne said, if i and j may be referring to complex values. But even if you fix that, there may be a bigger issue. If your intention is that i and j are loop counters, you almost certainly do _not_ want to be reseeding the generator every time though the loop(s). The only reason for wanting to do that is to ensure a certain kind of reproducability -- so that you can reproduce the results of any given iteration without going through the whole loop.

Take to heart this note in the (current version of the) help:

    Resetting the default stream to the same fixed state allows computations
    to be repeated. Setting the stream to different states leads to unique
    computations, however, it does not improve any statistical properties.