function [tvals,yvals]=FixedRK(fname,t0,y0,h,k,n)
tvals=[];yvals=[];
// [tvals,yvals] = FixedRK(fname,t0,y0,h,k,n)
// Produces approximate solution to the initial value problem
// 
//      y'(t) = f(t,y(t))     y(t0) = y0
// 
// using a strategy that is based upon a k-th order
// Runge-Kutta method. Stepsize is fixed.
// 
// fname = string that names the function f.
// t0 = initial time.
// y0 = initial condition vector.
// h  = stepsize.
// k  = order of method. (1<=k<=5).
// n  = number of steps to be taken,
// 
// tvals is a column vector with tvals(j) = t0 + (j-1)h, j=1:n+1
// yvals is a matrix with yvals(j,:) = approximate solution at tvals(j), j=1:n+1
 
tc = t0;
yc = y0;
tvals = tc;
yvals = yc';
fc = evstr(fname+'(tc,yc)');
for j = 1:n
  [tc,yc,fc] = RKstep(fname,tc,yc,fc,h,k);
  yvals = [yvals;yc'];
  tvals = [tvals;tc];
end