Re: What should I do to fix "warning: implicit conversion from real matrix to real scalar"?

[John B. Thoo]

On Jul 8, 2009, at 8:12 AM, Carlo de Falco wrote:

> On 8 Jul 2009, at 16:25, John B. Thoo wrote:
>
> > 1;
> >
> > function y = h (x)
> >
> > load ht_tf8M160ord9visc01.mat u;
> > x = u(:,5);
> >
> >   y = x.^2;
> >
> > endfunction
> >
> > quad ("h", 0, 1)
>
> the integrand function you pass to quad should return a scalar  
> output when given scalar input while your function h always returns  
> THE SAME vector ( u(:,5).^2 as stored in the file  
> ht_tf8M160ord9visc01.mat ) regardless of the input.
> c.

Hi, Carlo.  Thanks for the tip.  So, then, is using "trapz" in the  
following way my only recourse to find  \int H(u(:,t)) dx  for some  
function  H(x)  where  u(x,t)  is a matrix?

%%--------begin energy.m---------
clear all

global u;
load ht_tf8M160ord9visc01.mat;

function y = h (x)
global u;

  U = u(:,5);
  y = (U.^2).';

endfunction

trapz (x, h (x))
%%---------end energy.m----------

Or is there a way I can use either "quad" or "quadl"?  Thanks again.

---John.