C315: Riemann Zeta Function

Author(s): K.S. Kölbig Library: MATHLIB
Submitter: Submitted: 07.06.1992
Language: Fortran Revised:

Function subprograms RRIZET and DRIZET calculate the Riemann zeta function

displaymath93

for real arguments tex2html_wrap_inline95 , where tex2html_wrap_inline97 is defined by analytic continuation for x < 1. For x = 1, tex2html_wrap_inline103 has a pole of order one.

On CDC and Cray computers, the double-precision version DRIZET is not available.

Structure:

FUNCTION subprograms
User Entry Names: RRIZET, DRIZET
Files Referenced: Unit 6
External References: GAMMA, DGAMMA, MTLMTR, ABEND

Usage:

In any arithmetic expression,

RRIZET(X) or DRIZET(X)

has the value tex2html_wrap_inline105 if tex2html_wrap_inline107 , and tex2html_wrap_inline109 if tex2html_wrap_inline111 , where RRIZET is of type REAL, DRIZET is of type DOUBLE PRECISION, and where X has the same type as the function name.

Method:

Rational Chebyshev approximation. For tex2html_wrap_inline113 the reflection formula for tex2html_wrap_inline115 is used.

Accuracy:

RRIZET (except on CDC and Cray computers) has full single-precision accuracy. For most values of the argument X, DRIZET (and RRIZET on CDC and Cray computers) has an accuracy of approximately one significant digit less than the machine precision.

Error handling:

Error C315.1: tex2html_wrap_inline117 . The function value is set to zero, and a message is written on Unit 6, unless subroutine MTLSET (N002) has been called.

References:

  1. W.J. Cody, K.E. Hillstrom, and H.C. Thather, Jr., Chebyshev approximations for the
    Riemann zeta function, Math. Comp. 25 (1971) 537-547.
tex2html_wrap_inline119

Michel Goossens Tue Jun 4 21:24:32 METDST 1996