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Re: matlab compatibility of od45 with adaptive stepping
From: |
Carlo De Falco |
Subject: |
Re: matlab compatibility of od45 with adaptive stepping |
Date: |
Sun, 11 Oct 2015 11:22:33 +0000 |
On 11 Oct 2015, at 12:57, Sebastian Schoeps <address@hidden> wrote:
> But Carlo indicated that we might have to rewrite a lot.
Actually we need to delete a lot of code, but the new version will be much
simpler in the end.
In pseudo code the new version should be something as simple as:
---------------------------------------------------------------
function [t, x] = adaptive (fun, stepper, tspan, x0)
fixed_times = numel (tspan) > 2;
t_new = t_old = t = tspan(1);
x_new = x_old = x = x0;
dt = initial_step ();
iout = istep = 1;
while (t_old < tspan(end))
[t_new, x_new, error] = stepper (fun, t_old, x_old);
if (error < tol)
t_old = t_new;
x_old = x_new;
if (fixed_times)
t_caught = find ((t(iout:end) > t_old) & (t(iout:end) <= t_new));
if (! isempty (t_caught))
iout = max (t_caught);
x(:, t_caught) = interpolate ([t_old, t_new], [x_old, x_new],
t(t_caught));
istep++;
endif
else
t(++istep) = t_old = t_new;
x(:, istep) = x_old = x_new;
iout = istep;
endif
endif
dt = new_step (dt, error, tol);
endwhile
endfunction
---------------------------------------------------------------
The main difficulty in writing the patch is understanding all the output flags
and maintaining
compatibility so that high level interface functions such as ode45 do not
require too many modifications.
c.
- Re: matlab compatibility of od45 with adaptive stepping, Sebastian Schöps, 2015/10/15
- Re: matlab compatibility of od45 with adaptive stepping, Carlo De Falco, 2015/10/11
- Re: matlab compatibility of od45 with adaptive stepping, Sebastian Schoeps, 2015/10/15
- Re: matlab compatibility of od45 with adaptive stepping, Jacopo Corno, 2015/10/15
- Re: matlab compatibility of od45 with adaptive stepping, Sebastian Schoeps, 2015/10/15
- Re: matlab compatibility of od45 with adaptive stepping, Carlo De Falco, 2015/10/11
- Re: matlab compatibility of od45 with adaptive stepping,
Carlo De Falco <=
- Re: matlab compatibility of od45 with adaptive stepping, Carlo De Falco, 2015/10/15
- Re: matlab compatibility of od45 with adaptive stepping, Carlo De Falco, 2015/10/11