# Gentler transformation from real to positive

**URL:** <https://discourse.julialang.org/t/gentler-transformation-from-real-to-positive/33695>\
**Category:** Optimization (Mathematical)\
**Tags:** question\
**Created:** [January 23, 2020, 11:13am UTC](https://discourse.julialang.org/t/gentler-transformation-from-real-to-positive/33695 "2020-01-23T11:13:00Z")\
**Posts on this page:** 1\
**Showing post:** 11

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [January 23, 2020, 1:07pm UTC](https://discourse.julialang.org/t/gentler-transformation-from-real-to-positive/33695/11 "2020-01-23T13:07:47Z")

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> [@Tamas\_Papp](#):
>
> I should have specified, but I need a bijection (continuous, monotone; does not need to be continuously differentiable but that would be nice, too).

Why? Finding a root of f(p²) means that every root is doubled, but if Newton converges to a negative root you can just flip the sign.

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