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annotate +time/+expint/Magnus_mp.m @ 510:71908bbce2e1 feature/quantumTriangles

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tried to add 4th order magnus integrator which does not work
author Ylva Rydin <ylva.rydin@telia.com>
date Fri, 02 Jun 2017 17:46:01 +0200
parents 566304a5733e
children 4ef2d2a493f1
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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49bc2929dfb1 Added the midpont magnus exponential integrator
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1 % Takes one time step of size k using the magnus midpoinr
49bc2929dfb1 Added the midpont magnus exponential integrator
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2 % starting from v_0 and where the function F(v,t) gives the
49bc2929dfb1 Added the midpont magnus exponential integrator
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3 % time derivatives.
49bc2929dfb1 Added the midpont magnus exponential integrator
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4 function v = Magnus_mp(v,D, t , k)
49bc2929dfb1 Added the midpont magnus exponential integrator
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5
49bc2929dfb1 Added the midpont magnus exponential integrator
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6 if isa(D,'function_handle')
49bc2929dfb1 Added the midpont magnus exponential integrator
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7 % v = krylov(k*D(t +k/2*t),v);
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566304a5733e changed the magnus midpoint rule
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8 v = expm(k*D(t +k/2))*v;
505
49bc2929dfb1 Added the midpont magnus exponential integrator
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9 else
49bc2929dfb1 Added the midpont magnus exponential integrator
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10 %v = krylov(k*D,v);
49bc2929dfb1 Added the midpont magnus exponential integrator
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11 v = expm(k*D)*v;
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12 end
49bc2929dfb1 Added the midpont magnus exponential integrator
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13
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14 end