# Changing a placeholder between gradient steps

**URL:** <https://discourse.edwardlib.org/t/changing-a-placeholder-between-gradient-steps/674>\
**Category:** General\
**Created:** [March 13, 2018, 9:13pm UTC](https://discourse.edwardlib.org/t/changing-a-placeholder-between-gradient-steps/674 "2018-03-13T21:13:05Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![www3cam](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.edwardlib.org/www3cam/32/262_2.png) [@www3cam](https://discourse.edwardlib.org/u/www3cam)\
**Post date:** [March 13, 2018, 9:13pm UTC](https://discourse.edwardlib.org/t/changing-a-placeholder-between-gradient-steps/674/1 "2018-03-13T21:13:05Z")

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I have an algorithm I want to use edward for. However, I need to change the value of a placeholder after every gradient step. I know I can do the gradient steps one at a time with `inference.update()` however I don’t know how to change the value of the placeholder after I take the gradient step without running `ed.VariationalInference({z: qz}, data={x: x_train, beta: qbeta})` which would ruin my parameter values. Thanks,

Cameron

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**Author:** ![www3cam](https://yyz1.discourse-cdn.com/flex035/user_avatar/discourse.edwardlib.org/www3cam/32/262_2.png) [@www3cam](https://discourse.edwardlib.org/u/www3cam)\
**Post date:** [March 13, 2018, 9:14pm UTC](https://discourse.edwardlib.org/t/changing-a-placeholder-between-gradient-steps/674/2 "2018-03-13T21:14:34Z")

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Never mind I found it here after one second of googling: [http://edwardlib.org/api/inference-data-subsampling](http://edwardlib.org/api/inference-data-subsampling)