23 lines
545 B
Python
23 lines
545 B
Python
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# Verfahren von Heun zur numerischen Lösung von Anfangswertaufgaben.
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def heun(xk,yk,h,ys):
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xk1 = xk + h
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yk1p = yk + h * ys(xk,yk)
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yk1 = 0.5*(yk+yk1p+h*ys(xk1,yk1p))
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return (xk1,yk1p)
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def run_heun(K,h,x0,y0,ys):
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if not isinstance(ys,list): ys = [ys]
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if not isinstance(y0,list): y0 = [y0]
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xk = x0
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yk = y0
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xks = x0
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yks = [ [v] for v in y0 ]
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for i in range(K):
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for j in range(len(ys)):
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xk,yk[j] = heun(xk,yk[j],h,ys[i])
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xks.append(xk)
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yks[j].append(yk[j])
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