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BESSK0.PAS
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Wrap
Pascal/Delphi Source File
|
1991-04-29
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518b
|
17 lines
FUNCTION bessk0(x: real): real;
VAR
y,ans: double;
BEGIN
IF (x <= 2.0) THEN BEGIN
y := x*x/4.0;
ans := (-ln(x/2.0)*bessi0(x))+(-0.57721566+y*(0.42278420
+y*(0.23069756+y*(0.3488590e-1+y*(0.262698e-2
+y*(0.10750e-3+y*0.74e-5)))))) END
ELSE BEGIN
y := (2.0/x);
ans := (exp(-x)/sqrt(x))*(1.25331414+y*(-0.7832358e-1
+y*(0.2189568e-1+y*(-0.1062446e-1+y*(0.587872e-2
+y*(-0.251540e-2+y*0.53208e-3)))))) END;
bessk0 := sngl(ans)
END;