# Cosine Integral (G Dataflow)

Version:

Evaluates the cosine integral for any real nonnegative number.

## x

A real nonnegative number.

## error in

Error conditions that occur before this node runs. The node responds to this input according to standard error behavior.

Default: No error

## Ci(x)

Result of the calculation of the cosine integral for the given value of x.

## error out

Error information. The node produces this output according to standard error behavior.

## Algorithm for Evaluating the Cosine Integral

The following equation defines the cosine integral.

$Ci\left(x\right)=\gamma +\mathrm{ln}\left(|x|\right)+{\int }_{0}^{x}\frac{\mathrm{cos}\left(t\right)-1}{t}dt$

where $\gamma$ is the Euler constant.

The following illustration shows the graph of the cosine integral in the interval (0, 15).

Where This Node Can Run:

Desktop OS: Windows

FPGA: Not supported