# \#clpr

**URL:** https://swi-prolog.discourse.group/tag/clpr/80.md

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## [CLPR fails for 3d change of basis (precision / epsilon error ?)](https://swi-prolog.discourse.group/t/clpr-fails-for-3d-change-of-basis-precision-epsilon-error/6640)

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**Author:** [@BorisBocquet](https://swi-prolog.discourse.group/u/BorisBocquet)\
**Replies:** 6\
**Last updated:** [June 20, 2023, 8:37pm UTC](https://swi-prolog.discourse.group/t/clpr-fails-for-3d-change-of-basis-precision-epsilon-error/6640 "2023-06-20T20:37:11Z")

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I’m using: SWI-Prolog version 9.0.4 I want the code to: Implementation of a 3d change of basis. This is the formula : a\_M\_c = a\_M\_b \* b\_M\_c Where the matrices are 4x4 homogeneous matrices where the first 3x3 is the …

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## [{X + Y \>= 1} fails - bug?](https://swi-prolog.discourse.group/t/x-y-1-fails-bug/5193)

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**Author:** [@brebs](https://swi-prolog.discourse.group/u/brebs)\
**Replies:** 1\
**Last updated:** [March 31, 2022, 7:06am UTC](https://swi-prolog.discourse.group/t/x-y-1-fails-bug/5193 "2022-03-31T07:06:58Z")

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Given (as per example in docs): ?- use\_module(library(clpr)). ?- {X + Y \>= 1}. In swi-prolog 8.5.8 and 8.5.9 it fails: false. But in 8.4.2 and 8.5.7 it succeeds: {Y=1.0-X+\_A, \_A\>=0.0}. The 8.5.8 announcement did me…

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## [Clpr](https://swi-prolog.discourse.group/t/clpr/3485)

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**Author:** [@anniepoo](https://swi-prolog.discourse.group/u/anniepoo)\
**Replies:** 13\
**Last updated:** [January 14, 2021, 3:54pm UTC](https://swi-prolog.discourse.group/t/clpr/3485 "2021-01-14T15:54:48Z")

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Experimenting with clpr. Suppose I have two circles with radii R1 and R2 and centers AX,AY and BX,BY respectively, then I should be able to find their intersection circles :- R1 = 5, R2 = 5, AX = 0, AY…