21 lines
564 B
Fortran
21 lines
564 B
Fortran
FUNCTION ERFCX(X)
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C =================
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C
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C complementary error function
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C expression from Abramowitz and Stegun, p.299, Eq. 7.1.26
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C
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INCLUDE 'IMPLIC.FOR'
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PARAMETER (P = 0.3275911D0,
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* A1 = 0.254829592D0,
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* A2 =-0.284496736D0,
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* A3 = 1.421413741D0,
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* A4 =-1.453152027D0,
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* A5 = 1.061405429D0,
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* UN = 1.D0)
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T=UN/(UN+P*X)
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ERFCX=0.
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IF(X.GT.13.) RETURN
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ERFCX=T*(A1+T*(A2+T*(A3+T*(A4+T*A5))))*EXP(-X*X)
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RETURN
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END
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