HurwitzZeta

HurwitzZeta[s,a]

gives the Hurwitz zeta function .

Details

Mathematical function, suitable for both symbolic and numerical manipulation.
The Hurwitz zeta function is defined as an analytic continuation of .
HurwitzZeta is identical to Zeta for .
Unlike Zeta, HurwitzZeta has singularities at for non-negative integers .
HurwitzZeta has branch cut discontinuities in the complex plane running from to .
For certain special arguments, HurwitzZeta automatically evaluates to exact values.
HurwitzZeta can be evaluated to arbitrary numerical precision.
HurwitzZeta automatically threads over lists.

Examples

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Basic Examples (6)

Evaluate numerically:

Plot over a subset of the reals:

Plot over a subset of the complexes:

Series expansion at the origin:

Series expansion at Infinity:

Series expansion at a singular point:

Scope (33)

Numerical Evaluation (4)

Evaluate numerically:

Evaluate to high precision:

The precision of the output tracks the precision of the input:

Complex number input:

Evaluate efficiently at high precision:

Specific Values (5)

Simple exact values are generated automatically:

HurwitzZeta[s,a] for symbolic a:

HurwitzZeta[s,a] for symbolic s:

Values at zero:

Find a value of s for which HurwitzZeta[s,1]=1.05:

Visualization (3)

Plot the HurwitzZeta as a function of its parameter s:

Plot the HurwitzZeta function for various orders:

Plot the real part of HurwitzZeta function:

Plot the imaginary part of HurwitzZeta function:

Function Properties (11)

Real domain of :

For positive , this is simply :

For negative integer , the domain is just the negative integers:

Complex domain:

For positive , this is again :

Approximate function range of :

HurwitzZeta threads elementwise over lists:

HurwitzZeta is not an analytic function:

Nor is it meromorphic:

is neither non-decreasing nor non-increasing:

is not injective:

is surjective:

is not surjective:

is neither non-negative nor non-positive:

has both singularity and discontinuity for negative integers:

is neither convex nor concave:

TraditionalForm formatting:

Differentiation (3)

First derivative with respect to a:

Higher derivatives with respect to a:

Plot the higher derivatives with respect to a when s=3:

Formula for the derivative with respect to a:

Integration (3)

Compute the indefinite integral using Integrate:

Verify the anti-derivative:

Definite integral:

More integrals:

Series Expansions (2)

Find the Taylor expansion using Series:

Plots of the first three approximations around :

Taylor expansion at a generic point:

Function Identities and Simplifications (2)

HurwitzZeta is defined through the identity:

Recurrence identity:

Applications (1)

The word count in a text follows a Zipf distribution:

Fit a ZipfDistribution to the word frequency data:

Fit a truncated ZipfDistribution to counts at most 50 using rhohat as a starting value:

Visualize the CDFs up to the truncation value:

Estimate the proportion of the original data not included in the truncated model:

Properties & Relations (2)

HurwitzZeta can be generated by symbolic solvers:

For , two-argument Zeta coincides with HurwitzZeta:

Possible Issues (2)

HurwitzZeta differs from the two-argument form of Zeta by a different choice of branch cut:

HurwitzZeta includes singular terms, unlike Zeta:

Neat Examples (1)

ComplexPlot of HurwitzZeta function, as a function of with :

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