Need help with eval

[Doug Stewart]

I am using qtoctave with octave 2.9.15

When I copy and paste the results into eval it work as expected, but 
when I try and do it inline in the code then it gives me errors.

here is part of the code so you can see how I am making the string.

        else
           if(abs(abs(c)-1)<10*eps)  ## if c=1
           if(c>=0)
                if(b/a<0)
                       ss(q,1)=cellstr(sprintf(" e.^(t) .*( 
cos(%g*t)    %g *sin(%g*t))",d,(b/a),d)) ;
                    else
                       ss(q,1)=cellstr(sprintf(" e.^(t) .*( cos(%g*t) + 
%g *sin(%g*t))",d,(b/a),d)) ;
                    endif
           else
                if(b/a<0)
                   ss(q,1)=cellstr(sprintf(" e.^(-t) .*( cos(%g*t)    
%g *sin(%g*t))",d,(b/a),d)) ;
                else
                   ss(q,1)=cellstr(sprintf(" e.^(-t) .*( cos(%g*t) + %g 
*sin(%g*t))",d,(b/a),d)) ;
                endif
           endif
           else
               if(b/a<0)
                 ss(q,1)=cellstr(sprintf(" e.^(%g *t) .* ( cos(%g*t)   
%g *sin(%g*t))",c,d,(b/a),d) );     
               else
                 ss(q,1)=cellstr(sprintf(" e.^(%g *t) .*( cos(%g*t) + 
%g *sin(%g*t))",c,d,(b/a),d) );
           endif
        endif     
        endif
    endif  
    q=q+1;
    k=k-2;
 endif
endif
endwhile


ss
%%w='f(t)  =  ';
w='yy= ';
for h=1:q-1
 w=strcat(w,strvcat( ss(h,1)));
endfor

t=1:.01:3;
w
eval(w);

plot(t,yy);
ret=w;

endfunction





As you can see I am using a cell array and then putting all the cells 
into one string at the last.
If I take and copy the screen results of w and use it in an eval( ) 
function at the command prompt it works!!
But this code gives:

w = yy= -0.0555556 * ( cos(3*t) + -1 *sin(3*t)) + 0.0555556 * e.^(-3*t)

error: operator .^: nonconformant arguments (op1 is 3x1, op2 is 1x201)

error: evaluating binary operator `.^' near line 209, column 62

error: evaluating binary operator `*' near line 209, column 59

error: evaluating binary operator `+' near line 209, column 47

error: evaluating assignment expression near line 209, column 3

error: called from `ilt' in file `E:\qtoctave-0.6.8\M\ilt.m'


you can get the code at  dougs dot homeip dot net/octave/ilt.m

Obviously it is my attemp at doing the inverse laplace transforms.

to run this example use
n=1

d=poly([ +3j -3j -3 ])

sys=tf(n,d);

ilt(sys,'i')



Thanks in advance.
Doug Stewart