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bessK

bessK (n,x [, algorithm [, accuracy ]])​

warning

Obsolete -- use Besselk.

The bessK function returns the modified Bessel function of the second kind, Kn (x), of order n and argument x.

For real x, the optional parameter algorithm selects between a faster, less accurate calculation method and slower, more accurate methods. In addition, when algorithm is zero or absent, the order n is truncated to an integer.

When algorithm is included and is 1, accuracy can be used to specify the desired fractional accuracy. See below for details about algorithms.

If x is complex, a complex result is returned. In this case, algorithm and accuracy are ignored. The order n can be fractional, and must be real.

Details​

See the bessI function for details on algorithms, accuracy and speed of execution.

When algorithm is 1, pairs of values for bessJ and bessY are calculated simultaneously. The values are stored, and a subsequent call to bessJ after a call to bessK (or vice-versa) with the same n, x, and accuracy will be very fast.