# coqueraux: Fast, conceptually simple, iterative scheme for Weierstrass P... In elliptic: Weierstrass and Jacobi Elliptic Functions

## Description

Fast, conceptually simple, iterative scheme for Weierstrass P functions, following the ideas of Robert Coqueraux

## Usage

 `1` ```coqueraux(z, g, N = 5, use.fpp = FALSE, give = FALSE) ```

## Arguments

 `z` Primary complex argument `g` Invariants; if an object of type `parameters` is supplied, the invariants will be extracted appropriately `N` Number of iterations to use `use.fpp` Boolean, with default `FALSE` meaning to not reduce `z` to the fpp. Setting to `TRUE` reduces `z` to the fpp via `parameters()`: this is more accurate (see example) but slower `give` Boolean, with `TRUE` meaning to return an estimate of the error, and `FALSE` meaning to return just the value

## Author(s)

Robin K. S. Hankin

## References

R. Coqueraux, 1990. Iterative method for calculation of the Weierstrass elliptic function, IMA Journal of Numerical Analysis, volume 10, pp119-128

## Examples

 ```1 2 3 4 5 6 7``` ``` z <- seq(from=1+1i,to=30-10i,len=55) p <- P(z,c(0,1)) c.true <- coqueraux(z,c(0,1),use.fpp=TRUE) c.false <- coqueraux(z,c(0,1),use.fpp=FALSE) plot(1:55,abs(p-c.false)) points(1:55,abs(p-c.true),pch=16) ```

### Example output ```Attaching package: 'elliptic'

The following objects are masked from 'package:stats':

sd, sigma

The following object is masked from 'package:base':

is.primitive
```

elliptic documentation built on May 2, 2019, 9:37 a.m.