lightning/docs/source-pytorch/common/precision_basic.rst

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.. _precision_basic:
#######################
N-Bit Precision (Basic)
#######################
**Audience:** Users looking to train models faster and consume less memory.
----
If you're looking to run models faster or consume less memory, consider tweaking the precision settings of your models.
Lower precision, such as 16-bit floating-point, requires less memory and enables training and deploying larger models.
Higher precision, such as the 64-bit floating-point, can be used for highly sensitive use-cases.
----
****************
16-bit Precision
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Use 16-bit mixed precision to lower your memory consumption by up to half so that you can train and deploy larger models. If your GPUs are [`Tensor Core <https://docs.nvidia.com/deeplearning/performance/mixed-precision-training/index.html>`_] GPUs, you can also get a ~3x speed improvement. Half precision can sometimes lead to unstable training.
.. code::
Trainer(precision='16-mixed')
----
****************
32-bit Precision
****************
32-bit precision is the default used across all models and research. This precision is known to be stable in contrast to lower precision settings.
.. testcode::
Trainer(precision='32-true')
# or
Trainer(precision='32')
# or
Trainer(precision=32)
----
****************
64-bit Precision
****************
For certain scientific computations, 64-bit precision enables more accurate models. However, doubling the precision from 32 to 64 bit also doubles the memory requirements.
.. testcode::
Trainer(precision='64-true')
# or
Trainer(precision='64')
# or
Trainer(precision=64)
.. note::
Since in deep learning, memory is always a bottleneck, especially when dealing with a large volume of data and with limited resources.
It is recommended using single precision for better speed. Although you can still use it if you want for your particular use-case.
----
********************************
Precision support by accelerator
********************************
.. list-table:: Precision with Accelerators
:widths: 20 20 20 20 20
:header-rows: 1
* - Precision
- CPU
- GPU
- TPU
- IPU
* - 16 Mixed
- No
- Yes
- No
- Yes
* - BFloat16 Mixed
- Yes
- Yes
- Yes
- No
* - 32 True
- Yes
- Yes
- Yes
- Yes
* - 64 True
- Yes
- Yes
- No
- No