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NAG[s18cdc] NAG[nag_bessel_k1_scaled] - Scaled modified Bessel function ](/support/helpjp/helpview.aspx?si=9767/file08667/math6.png)
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Calling Sequence
s18cdc(x, 'fail'=fail)
nag_bessel_k1_scaled(. . .)
Parameters
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x - float;
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On entry: the argument  of the function.
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Constraint:  . If x is too close to zero, there is a danger of overflow, and a failure will occur. .
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'fail'=fail - table; (optional)
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The NAG error argument, see the documentation for NagError.
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Description
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Purpose
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nag_bessel_k1_scaled (s18cdc) returns a value of the scaled modified Bessel function ](/support/helpjp/helpview.aspx?si=9767/file08667/math50.png) .
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Error Indicators and Warnings
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"NE_REAL_ARG_LE"
On entry, x must not be less than or equal to 0.0:  .
![k[1]](/support/helpjp/helpview.aspx?si=9767/file08667/math86.png) is undefined and the function returns zero.
"NE_REAL_ARG_TOO_SMALL"
On entry, x must be greater than  :  . The function returns the value of the function at the smallest permitted value of the argument.
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Accuracy
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Relative errors in the argument are attenuated when propagated into the function value. When the accuracy of the argument is essentially limited by the machine precision, the accuracy of the function value will be similarly limited by at most a small multiple of the machine precision.
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Examples
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>
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x := 0.4:
NAG:-s18cdc(x);
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