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view +time/+rk4/get_rk4_time_step.m @ 87:0a29a60e0b21

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In Curve: Rearranged for speed. arc_length_fun is now a property of Curve. If it is not supplied, it is computed via the derivative and spline fitting. Switching to the arc length parameterization is much faster now. The new stuff can be tested with testArcLength.m (which should be deleted after that).
author Martin Almquist <martin.almquist@it.uu.se>
date Sun, 29 Nov 2015 22:23:09 +0100
parents 48b6fb693025
children
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% Calculate the size of the largest time step given the largest evalue for a operator with pure imaginary e.values.
function k = get_rk4_time_step(lambda,l_type)
    default_arg('l_type','complex')

    rad = abs(lambda);
    if strcmp(l_type,'real')
        % Real eigenvalue
        % kl > -2.7852
        k = 2.7852/rad;

    elseif strcmp(l_type,'imag')
        % Imaginary eigenvalue
        % |kl| < 2.8284
        k = 2.8284/rad;
    elseif strcmp(l_type,'complex')
        % |kl| < 2.5
        k = 2.5/rad;
    else
        error('l_type must be one of ''real'',''imag'' or ''complex''.')
    end
end