# Re: st: assignment by indexing

 From "Michael Blasnik" To Subject Re: st: assignment by indexing Date Wed, 4 Feb 2004 11:19:37 -0500

```if p1, p2, etc.. just represent the same quantities at different times, I'm
not sure why you don't reshape long?

reshape long p, i(idvar) j(time)

then all your statements could be done in 2 steps:

replace p=invlogit(`lgtp1' ) in 1
replace p=p[_n-1]*`ka'+(1-p[_n-1])*`mu' in 2/l

Michael Blasnik
michael.blasnik@verizon.net

----- Original Message -----
From: "Ben Pelzer" <b.pelzer@maw.kun.nl>
To: <statalist@hsphsun2.harvard.edu>
Sent: Wednesday, February 04, 2004 9:10 AM
Subject: RE: st: assignment by indexing

> Nick,
>
> Your answer yesterday was clear. I was looking for a neat way to solve the
> problem, but finally decided to use the following set of commands for a
> similar, yet smaller, problem of only 13 timepoints:
>
>   quietly replace   `p1' = invlogit(`lgtp1');
>   quietly replace   `p2'  = `p1'  * `ka' + (1-`p1'  ) * `mu'
>   quietly replace   `p3'  = `p2'  * `ka' + (1-`p2'  ) * `mu'
>   quietly replace   `p4'  = `p3'  * `ka' + (1-`p3'  ) * `mu'
>   quietly replace   `p5'  = `p4'  * `ka' + (1-`p4'  ) * `mu'
>   quietly replace   `p6'  = `p5'  * `ka' + (1-`p5'  ) * `mu'
>   quietly replace   `p7'  = `p6'  * `ka' + (1-`p6'  ) * `mu'
>   quietly replace   `p8'  = `p7'  * `ka' + (1-`p7'  ) * `mu'
>   quietly replace   `p9'  = `p8'  * `ka' + (1-`p8'  ) * `mu'
>   quietly replace   `p10' = `p9'  * `ka' + (1-`p9'  ) * `mu'
>   quietly replace   `p11' = `p10' * `ka' + (1-`p10' ) * `mu'
>   quietly replace   `p12' = `p11' * `ka' + (1-`p11' ) * `mu'
>   quietly replace   `p13' = `p12' * `ka' + (1-`p12' ) * `mu'
>
> Here, ka and mu are the transition probs. Of course, following your
> matrix-suggestion would solve all problems but also cause some extra work,
> while copying statements is very fast... I didn't know the 'egen'
statement,
> so, I'll have a look at it right away. Thanks again, Ben.
>

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