# PreciseSums v0.3

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## Accurate Floating Point Sums and Products

Most of the time floating point arithmetic does
approximately the right thing. When adding sums or having products
of numbers that greatly differ in magnitude, the floating point
arithmetic may be incorrect. This package implements the Kahan
(1965) sum <doi:10.1145/363707.363723>, Neumaier (1974) sum
<doi:10.1002/zamm.19740540106>, pairwise-sum (adapted from 'NumPy',
See Castaldo (2008) <doi:10.1137/070679946> for a discussion of
accuracy), and arbitrary precision sum (adapted from the fsum in
'Python' ; Shewchuk (1997)
<http://www.cs.berkeley.edu/~jrs/papers/robustr.pdf>). In addition,
products are changed to long double precision for accuracy, or
changed into a log-sum for accuracy.

## Functions in PreciseSums

Name | Description | |

neumaierSum | Using the Neumaier method, take a more accurate sum | |

fsum | Return an accurate floating point sum of values | |

kahanSum | Using the Kahan method, take a more accurate sum | |

psProd | Using PreciceSums's default method, take a product | |

psSetProd | Choose the type of product to use in PreciceSums. These are used in the PreciceSums prod blocks | |

psSetSum | Choose the type of sums to use for PreciceSums. | |

psSum | Using PreciceSums's default method, take a sum | |

pairwiseSum | Return an accurate floating point sum of values | |

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## Details

License | GPL (>= 2) |

Encoding | UTF-8 |

LazyData | true |

RoxygenNote | 6.0.1 |

NeedsCompilation | yes |

Packaged | 2018-04-12 16:16:37 UTC; FIDLEMA3 |

Repository | CRAN |

Date/Publication | 2018-04-12 17:03:06 UTC |

depends | R (>= 3.2) |

suggests | testthat |

Contributors | Jonathan Shewchuk, Raymond Hettinger, Julian Taylor, Nathaniel Smith, NumPy Team , Python Team |

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