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annotate +time/+rk4/rungekutta_4.m @ 1227:02dfe3a56742 feature/poroelastic

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Add Upwind ElasticAnisotropic schemes. Seem to work really well!
author Martin Almquist <malmquist@stanford.edu>
date Sat, 16 Nov 2019 14:26:06 -0800
parents 48b6fb693025
children
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48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
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1 % Takes one time step of size k using the rungekutta method
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
parents:
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2 % starting from v_0 and where the function F(v,t) gives the
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
parents:
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3 % time derivatives.
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
parents:
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4 function v = rungekutta_4(v, t , k, F)
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
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5 k1 = F(v ,t );
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Jonatan Werpers <jonatan@werpers.com>
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6 k2 = F(v+0.5*k*k1,t+0.5*k);
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
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7 k3 = F(v+0.5*k*k2,t+0.5*k);
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
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8 k4 = F(v+ k*k3,t+ k);
48b6fb693025 Initial commit.
Jonatan Werpers <jonatan@werpers.com>
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9 v = v + (1/6)*(k1+2*(k2+k3)+k4)*k;
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Jonatan Werpers <jonatan@werpers.com>
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10 end