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annotate +time/+rkparameters/rk4.m @ 1118:07d0caf915e4 feature/poroelastic

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Introduce optFlag so that one can choose not to build the optimization-related cell of matrices called B. It is too computationally costly and should probably be done in a different way.
author Martin Almquist <malmquist@stanford.edu>
date Sun, 05 May 2019 19:05:31 -0700
parents ee4cfb37534d
children
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ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
Martin Almquist <malmquist@stanford.edu>
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1 function [a,b,c,s] = rk4()
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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2
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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3 % Butcher tableau for classical RK$
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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4 s = 4;
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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5 a = sparse(s,s);
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6 a(2,1) = 1/2;
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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7 a(3,2) = 1/2;
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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8 a(4,3) = 1;
ee4cfb37534d Merge with feature/d1_staggered to get RK timestepper for discrete data.
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9 b = 1/6*[1; 2; 2; 1];
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10 c = [0; 1/2; 1/2; 1];
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parents:
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