19 lines
447 B
Mathematica
19 lines
447 B
Mathematica
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function ellk=ellkVec(k)
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% Computes polynomial approximation for the complete elliptic
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% integral of the first kind (Hasting's approximation):
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m1=1-k.*k;
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m1(m1<eps)=eps;
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a0=1.38629436112;
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a1=0.09666344259;
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a2=0.03590092383;
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a3=0.03742563713;
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a4=0.01451196212;
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b0=0.5;
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b1=0.12498593597;
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b2=0.06880248576;
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b3=0.03328355346;
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b4=0.00441787012;
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ek1=a0+m1.*(a1+m1.*(a2+m1.*(a3+m1*a4)));
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ek2=(b0+m1.*(b1+m1.*(b2+m1.*(b3+m1*b4)))).*log(m1);
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ellk=ek1-ek2;
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