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annotate +time/+expint/Magnus_mp.m @ 506:2047ff9640b3 feature/quantumTriangles

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tried to make a symmetric scheme
author Ylva Rydin <ylva.rydin@telia.com>
date Mon, 29 May 2017 13:54:16 +0200
parents 49bc2929dfb1
children 566304a5733e
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505
49bc2929dfb1 Added the midpont magnus exponential integrator
Ylva Rydin <ylva.rydin@telia.com>
parents:
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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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parents:
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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
Ylva Rydin <ylva.rydin@telia.com>
parents:
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3 % time derivatives.
49bc2929dfb1 Added the midpont magnus exponential integrator
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parents:
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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
Ylva Rydin <ylva.rydin@telia.com>
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7 % v = krylov(k*D(t +k/2*t),v);
49bc2929dfb1 Added the midpont magnus exponential integrator
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parents:
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8 v = expm(k*D(t +k/2*t))*v;
49bc2929dfb1 Added the midpont magnus exponential integrator
Ylva Rydin <ylva.rydin@telia.com>
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9 else
49bc2929dfb1 Added the midpont magnus exponential integrator
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parents:
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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;
49bc2929dfb1 Added the midpont magnus exponential integrator
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12 end
49bc2929dfb1 Added the midpont magnus exponential integrator
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13
49bc2929dfb1 Added the midpont magnus exponential integrator
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14 end