[ADMB Users] Implementing a convolution in the GLOBAL_SECTION

[Weihai Liu]

should move
 dvar_vector y(1,n+m-1);

after following lines
  m=size_count(x);
  n=size_count(h);


weihai

On Fri, May 25, 2012 at 4:41 AM, Øigård Tor Arne
<tor.arne.oeigaard at imr.no>wrote:

> Hi all,
>
> I tried to implement a convolution in the GLOBAL_SECTION so that I can
> call a function conv(x,h) in the PROCEDURE_SECTION. The program compiles,
> but does not run, get the error message "size of file cmpdiff.tmp = 0" in
> the log.
>
> I read in two vectors x and h in the DATA_SECTION and want to create a
> vector y = conv(x,h) in the PROCEDURE_SECTION. The variable y has been
> declared as a vector in the PARAMETER_SECTION. In the GLOBAL_SECTION i
> added:
>
> #include <admodel.h>
>
>   dvar_vector conv1(const dvar_vector& x, const dvar_vector& h)
>   {
>
>   int k,j,m,n;
>   dvector lowerlimit(1,2);
>   dvector upperlimit(1,2);
>   dvar_vector y(1,n+m-1);
>
>   m=size_count(x);
>   n=size_count(h);
>
>   for(k=1;k<=(int) (m+n-1);k++)
>    {
>    y(k) = 0;
>    lowerlimit(1) = 1;
>    lowerlimit(2) = k+1-n;
>    upperlimit(1) = k;
>    upperlimit(2) = m;
>
>     for(j=max(lowerlimit);j<=(int) min(upperlimit);j++)
>        {
>        y(k) = y(k) + x(j)*h(k-j+1);
>        }
>    }
>
>  return y;
>
>   }
>
> So the local variable y in the function is declared as a dvar_vector, and
> the function is declared as a dvar_vector. I wonder if the problem has
> something to do with that.
>
> I tried to make another conv-function (below) which only returns one
> element of the output vector y, i.e., y_i, instead of the whole vector y,
> and then run a loop in the PROCEDURE_SECTION (the first loop in the
> conv1-function was moved to the PROCEDURE_SECTION). In this scenario the
> function conv2 is declared as a dvariable, and the local variable y
> (scalar) is declared as a dvariable. In this case it worked like a charm.
> Hence, it looks like I do something wrong when declaring the variables for
> the conv1-function. I also tried to replace the dvar_vector declaration for
> the conv1 and the local y vector with a dvector, but that did not help much.
>
>
>    dvariable conv2(const dvar_vector& x, const dvar_vector& h, const
> double& k)
>   {
>
>   int j,m,n;
>   dvector lowerlimit(1,2);
>   dvector upperlimit(1,2);
>   dvariable y;
>
>   m=size_count(x);
>   n=size_count(h);
>
>    y = 0;
>    lowerlimit(1) = 1;
>    lowerlimit(2) = k+1-n;
>    upperlimit(1) = k;
>    upperlimit(2) = m;
>
>
>     for(j=max(lowerlimit);j<=(int) min(upperlimit);j++)
>        {
>        y = y + x(j)*h(k-j+1);
>        }
>
>  return y;
>
>   }
>
> Any good advice is very much appreciated.
>
> Kind regards,
> Tor Arne
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