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QL10.FOR
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1985-11-29
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C
C ..................................................................
C
C SUBROUTINE QL10
C
C PURPOSE
C TO COMPUTE INTEGRAL(EXP(-X)*FCT(X), SUMMED OVER X FROM 0
C TO INFINITY).
C
C USAGE
C CALL QL10(FCT,Y)
C PARAMETER FCT REQUIRES AN EXTERNAL STATEMENT
C
C DESCRIPTION OF PARAMETERS
C FCT - THE NAME OF AN EXTERNAL FUNCTION SUBPROGRAM USED.
C Y - THE RESULTING INTEGRAL VALUE.
C
C REMARKS
C NONE
C
C SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED
C THE EXTERNAL FUNCTION SUBPROGRAM FCT(X) MUST BE FURNISHED
C BY THE USER.
C
C METHOD
C EVALUATION IS DONE BY MEANS OF 10-POINT GAUSSIAN-LAGUERRE
C QUADRATURE FORMULA, WHICH INTEGRATES EXACTLY WHENEVER
C FCT(X) IS A POLYNOMIAL UP TO DEGREE 19.
C FOR REFERENCE, SEE
C V.I.KRYLOV, APPROXIMATE CALCULATION OF INTEGRALS,
C MACMILLAN, NEW YORK/LONDON, 1962, PP.130-132 AND 347-352.
C
C ..................................................................
C
SUBROUTINE QL10(FCT,Y)
C
C
X=29.92070
Y=.9911827E-12*FCT(X)
X=21.99659
Y=Y+.1839565E-8*FCT(X)
X=16.27926
Y=Y+.4249314E-6*FCT(X)
X=11.84379
Y=Y+.2825923E-4*FCT(X)
X=8.330153
Y=Y+.7530084E-3*FCT(X)
X=5.552496
Y=Y+.009501517*FCT(X)
X=3.401434
Y=Y+.06208746*FCT(X)
X=1.808343
Y=Y+.2180683*FCT(X)
X=.7294545
Y=Y+.4011199*FCT(X)
X=.1377935
Y=Y+.3084411*FCT(X)
RETURN
END