# Spatial Pooler Implementation for MNIST Dataset

**URL:** <https://discourse.numenta.org/t/spatial-pooler-implementation-for-mnist-dataset/2317>\
**Category:** Implementations\
**Tags:** spatial-pooling, htm-implementations\
**Created:** [May 13, 2017, 4:23pm UTC](https://discourse.numenta.org/t/spatial-pooler-implementation-for-mnist-dataset/2317 "2017-05-13T16:23:22Z")\
**Posts on this page:** 1\
**Showing post:** 32

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**Author:** ![dmac](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.numenta.org/dmac/32/5842_2.png) [@dmac](https://discourse.numenta.org/u/dmac)\
**Post date:** [August 16, 2020, 3:14pm UTC](https://discourse.numenta.org/t/spatial-pooler-implementation-for-mnist-dataset/2317/32 "2020-08-16T15:14:36Z")

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Hi Shiva,

HTM.Core currently only implements the “exp” and “none” boosting functions.  
In the past, Breznak and I have tried to make the boosting function changeable, but that work never made it into the main branch of the project. For personal experimentation, you can modify the C++ function which controls boosting.

The boosting function is located at:  
File: `github/htm.core/src/htm/algorithms/SpatialPooler.cpp`  
Line 766:  
`output[i] = exp((targetDensity - actualDensity[i]) * boost);`

Hope This Helps

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