function [besi1eresult,x]=besi1e(x);
besi1eresult=[];
persistent ai12cs ai1cs besi1e bi1cs first firstCall ntai1 ntai12 nti1 xmin xsml y ; if isempty(firstCall),firstCall=1;end;
if isempty(ai12cs), ai12cs=zeros(1,22); end;
if isempty(ai1cs), ai1cs=zeros(1,21); end;
if isempty(besi1eresult), besi1eresult=0; end;
if isempty(bi1cs), bi1cs=zeros(1,11); end;
if isempty(xmin), xmin=0; end;
if isempty(xsml), xsml=0; end;
if isempty(y), y=0; end;
if isempty(ntai1), ntai1=0; end;
if isempty(ntai12), ntai12=0; end;
if isempty(nti1), nti1=0; end;
%***BEGIN PROLOGUE BESI1E
%***PURPOSE Compute the exponentially scaled modified (hyperbolic)
% Bessel function of the first kind of order one.
%***LIBRARY SLATEC (FNLIB)
%***CATEGORY C10B1
%***TYPE SINGLE PRECISION (BESI1E-S, DBSI1E-D)
%***KEYWORDS EXPONENTIALLY SCALED, FIRST KIND, FNLIB,
% HYPERBOLIC BESSEL FUNCTION, MODIFIED BESSEL FUNCTION,
% ORDER ONE, SPECIAL FUNCTIONS
%***AUTHOR Fullerton, W., (LANL)
%***DESCRIPTION
%
% BESI1E(X) calculates the exponentially scaled modified (hyperbolic)
% Bessel function of the first kind of order one for real argument X;
% i.e., EXP(-ABS(X))*I1(X).
%
% Series for BI1 on the interval 0. to 9.00000D+00
% with weighted error 2.40E-17
% log weighted error 16.62
% significant figures required 16.23
% decimal places required 17.14
%
% Series for AI1 on the interval 1.25000D-01 to 3.33333D-01
% with weighted error 6.98E-17
% log weighted error 16.16
% significant figures required 14.53
% decimal places required 16.82
%
% Series for AI12 on the interval 0. to 1.25000D-01
% with weighted error 3.55E-17
% log weighted error 16.45
% significant figures required 14.69
% decimal places required 17.12
%
%***REFERENCES (NONE)
%***ROUTINES CALLED CSEVL, INITS, R1MACH, XERMSG
%***REVISION HISTORY (YYMMDD)
% 770401 DATE WRITTEN
% 890210 REVISION DATE from Version 3.2
% 891214 Prologue converted to Version 4.0 format. (BAB)
% 900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
% 900326 Removed duplicate information from DESCRIPTION section.
% (WRB)
% 920618 Removed space from variable names. (RWC, WRB)
%***end PROLOGUE BESI1E
if isempty(first), first=false; end;
if firstCall, bi1cs(1)=[-.001971713261099859e0]; end;
if firstCall, bi1cs(2)=[.40734887667546481e0]; end;
if firstCall, bi1cs(3)=[.034838994299959456e0]; end;
if firstCall, bi1cs(4)=[.001545394556300123e0]; end;
if firstCall, bi1cs(5)=[.000041888521098377e0]; end;
if firstCall, bi1cs(6)=[.000000764902676483e0]; end;
if firstCall, bi1cs(7)=[.000000010042493924e0]; end;
if firstCall, bi1cs(8)=[.000000000099322077e0]; end;
if firstCall, bi1cs(9)=[.000000000000766380e0]; end;
if firstCall, bi1cs(10)=[.000000000000004741e0]; end;
if firstCall, bi1cs(11)=[.000000000000000024e0]; end;
if firstCall, ai1cs(1)=[-.02846744181881479e0]; end;
if firstCall, ai1cs(2)=[-.01922953231443221e0]; end;
if firstCall, ai1cs(3)=[-.00061151858579437e0]; end;
if firstCall, ai1cs(4)=[-.00002069971253350e0]; end;
if firstCall, ai1cs(5)=[.00000858561914581e0]; end;
if firstCall, ai1cs(6)=[.00000104949824671e0]; end;
if firstCall, ai1cs(7)=[-.00000029183389184e0]; end;
if firstCall, ai1cs(8)=[-.00000001559378146e0]; end;
if firstCall, ai1cs(9)=[.00000001318012367e0]; end;
if firstCall, ai1cs(10)=[-.00000000144842341e0]; end;
if firstCall, ai1cs(11)=[-.00000000029085122e0]; end;
if firstCall, ai1cs(12)=[.00000000012663889e0]; end;
if firstCall, ai1cs(13)=[-.00000000001664947e0]; end;
if firstCall, ai1cs(14)=[-.00000000000166665e0]; end;
if firstCall, ai1cs(15)=[.00000000000124260e0]; end;
if firstCall, ai1cs(16)=[-.00000000000027315e0]; end;
if firstCall, ai1cs(17)=[.00000000000002023e0]; end;
if firstCall, ai1cs(18)=[.00000000000000730e0]; end;
if firstCall, ai1cs(19)=[-.00000000000000333e0]; end;
if firstCall, ai1cs(20)=[.00000000000000071e0]; end;
if firstCall, ai1cs(21)=[-.00000000000000006e0]; end;
if firstCall, ai12cs(1)=[.02857623501828014e0]; end;
if firstCall, ai12cs(2)=[-.00976109749136147e0]; end;
if firstCall, ai12cs(3)=[-.00011058893876263e0]; end;
if firstCall, ai12cs(4)=[-.00000388256480887e0]; end;
if firstCall, ai12cs(5)=[-.00000025122362377e0]; end;
if firstCall, ai12cs(6)=[-.00000002631468847e0]; end;
if firstCall, ai12cs(7)=[-.00000000383538039e0]; end;
if firstCall, ai12cs(8)=[-.00000000055897433e0]; end;
if firstCall, ai12cs(9)=[-.00000000001897495e0]; end;
if firstCall, ai12cs(10)=[.00000000003252602e0]; end;
if firstCall, ai12cs(11)=[.00000000001412580e0]; end;
if firstCall, ai12cs(12)=[.00000000000203564e0]; end;
if firstCall, ai12cs(13)=[-.00000000000071985e0]; end;
if firstCall, ai12cs(14)=[-.00000000000040836e0]; end;
if firstCall, ai12cs(15)=[-.00000000000002101e0]; end;
if firstCall, ai12cs(16)=[.00000000000004273e0]; end;
if firstCall, ai12cs(17)=[.00000000000001041e0]; end;
if firstCall, ai12cs(18)=[-.00000000000000382e0]; end;
if firstCall, ai12cs(19)=[-.00000000000000186e0]; end;
if firstCall, ai12cs(20)=[.00000000000000033e0]; end;
if firstCall, ai12cs(21)=[.00000000000000028e0]; end;
if firstCall, ai12cs(22)=[-.00000000000000003e0]; end;
if firstCall, first=[true]; end;
firstCall=0;
%***FIRST EXECUTABLE STATEMENT BESI1E
if( first )
[nti1 ,bi1cs]=inits(bi1cs,11,0.1.*r1mach(3));
[ntai1 ,ai1cs]=inits(ai1cs,21,0.1.*r1mach(3));
[ntai12 ,ai12cs]=inits(ai12cs,22,0.1.*r1mach(3));
%
xmin = 2.0.*r1mach(1);
xsml = sqrt(4.5.*r1mach(3));
end;
first = false;
%
y = abs(x);
if( y>3.0 )
%
if( y<=8. )
besi1eresult =(.375+csevl((48../y-11.)./5.,ai1cs,ntai1))./sqrt(y);
end;
if( y>8. )
besi1eresult =(.375+csevl(16../y-1.0,ai12cs,ntai12))./sqrt(y);
end;
besi1eresult = (abs(besi1eresult).*sign(x));
else;
%
besi1eresult = 0.0;
if( y==0.0 )
csnil=dbstack(1); csnil=csnil(1).name(1)~='@';
if csnil&&~isempty(inputname(1)), assignin('caller','FUntemp',x); evalin('caller',[inputname(1),'=FUntemp;']); end
return;
end;
%
if( y<=xmin )
xermsg('SLATEC','BESI1E','ABS(X) SO SMALL I1 UNDERFLOWS',1,1);
end;
if( y>xmin )
besi1eresult = 0.5.*x;
end;
if( y>xsml )
besi1eresult = x.*(.875+csevl(y.*y./4.5-1.,bi1cs,nti1));
end;
besi1eresult = exp(-y).*besi1eresult;
csnil=dbstack(1); csnil=csnil(1).name(1)~='@';
if csnil&&~isempty(inputname(1)), assignin('caller','FUntemp',x); evalin('caller',[inputname(1),'=FUntemp;']); end
return;
end;
%
csnil=dbstack(1); csnil=csnil(1).name(1)~='@';
if csnil&&~isempty(inputname(1)), assignin('caller','FUntemp',x); evalin('caller',[inputname(1),'=FUntemp;']); end
end
%DECK BESI1
