# Powell optimizer cannot work properly

**URL:** https://discourse.itk.org/t/powell-optimizer-cannot-work-properly/6014
**Category:** Algorithms
**Tags:** itk, registration
**Created:** [June 24, 2023, 8:48am UTC](https://discourse.itk.org/t/powell-optimizer-cannot-work-properly/6014 "2023-06-24T08:48:18Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![suzume](https://discourse.itk.org/letter_avatar_proxy/v4/letter/s/6a8cbe/32.png) [@suzume](https://discourse.itk.org/u/suzume)
#### Post date: [June 24, 2023, 8:48am UTC](https://discourse.itk.org/t/powell-optimizer-cannot-work-properly/6014/1 "2023-06-24T08:48:18Z")

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Hi, I want to use the PowellOptimizer as the optimizer in registration. However, when I use PowellOptimizer, the registration cannot start and it stuck at the beginning as shown below:

 ![截屏2023-06-24 16.36.12](https://discourse.itk.org/uploads/default/original/2X/d/dd4fd98223856df68f027976202cdff86b2cc3db.png)  
It always staying the “Starting the registration now…”.  
I have tested the use of PowellOptimizer in itkPowellOptimizerTest.cxx and got the “test passed” results.  
 ![截屏2023-06-24 16.34.32](https://discourse.itk.org/uploads/default/original/2X/7/730733aa19b27b6004df6b5b9338de38ca4ab699.png)

On the other hand, when the AmoebaOptimizer was used as the optimizer in registration, the registration can normally work. So I think it may not by the problem of the registration.

 ![截屏2023-06-24 16.44.48](https://discourse.itk.org/uploads/default/original/2X/8/8a803fa0e0a8b04d6f336875d2d7ff5773fa93ad.png)

I want to know why the PowellOptimizer cannot work properly in registation?