Platforms: Unix, Windows
The config module contains many attributes that modify Theano’s behavior. Many of these attributes are consulted during the import of the theano module and many are assumed to be read-only.
As a rule, the attributes in this module should not be modified by user code.
Theano’s code comes with default values for these attributes, but you can override them from your .theanorc file, and override those values in turn by the THEANO_FLAGS environment variable.
The order of precedence is:
You can print out the current/effective configuration at any time by printing theano.config. For example, to see a list of all active configuration variables, type this from the command-line:
python -c 'import theano; print theano.config' | less
This is a list of comma-delimited key[=value] pairs that control Theano’s behavior. A key that appears without an ‘=value’ must be for a boolean value, and it acts as setting it to True.
For example, in bash, you can override your THEANORC defaults for <myscript>.py by typing this:
THEANO_FLAGS='floatX=float32,device=gpu0,nvcc.fastmath' python <myscript>.py
If a value is defined several times in THEANO_FLAGS, the right-most definition is used. So, for instance, if THEANO_FLAGS='device=cpu,device=gpu0', then gpu0 will be used.
The location[s] of the .theanorc file[s] in ConfigParser format. It defaults to $HOME/.theanorc.
Here is the .theanorc equivalent to the THEANO_FLAGS in the example above:
[global]
floatX = float32
device = gpu0
[nvcc]
fastmath = True
Multiple configuration files can be specified by separating them with ‘:’ characters (as in $PATH). Multiple configuration files will be merged, with later (right-most) files taking priority over earlier files in the case that multiple files specify values for a common configuration option. For example, to override system-wide settings with personal ones, set THEANORC=/etc/theanorc:~/.theanorc.
The rest of this page describes some of the more common and important flags that you might want to use. For the complete list (including documentation), import theano and print the config variable, as in:
python -c 'import theano; print theano.config' | less
String value: either ‘cpu’, ‘gpu0’, ‘gpu1’, ‘gpu2’, or ‘gpu3’
Choose the default compute device for theano graphs. Setting this to a gpu string will make the corresponding graphics device the default storage for shared tensor variables with dtype float32.
String value: either ‘float64’ or ‘float32’.
Default: ‘float64’
This sets the default dtype returned by tensor.matrix(), tensor.vector(), and similar functions. It also sets the default theano bit width for arguments passed as Python floating-point numbers.
String value: ‘FAST_RUN’, ‘FAST_COMPILE’, ‘PROFILE_MODE’, ‘DEBUG_MODE’
Default ‘FAST_RUN’
This sets the default compilation mode for theano functions.
Default: env-variable $HOME
This is used to compute the compiledir and base_compiledir attributes
Default: $HOME/.theano
This directory stores the architecture-dependent compilation directories.
Default: $HOME/.theano/<arch-identifier>
This directory stores dynamically-compiled modules for a particular architecture.
Default: ‘-lblas’
Link arguments to link against a (Fortran) level-3 blas implementation.
Default: $CUDA_ROOT or failing that, “/usr/local/cuda”
A directory with bin/, lib/, include/ folders containing cuda utilities.
Default: “”
Extra parameters to pass to gcc when compiling. Extra include paths, library paths, configuration options, etc.
Default: “”
A list of optimizer tags that we don’t want included in the default Mode. If multiple tags, separate them by ‘:’. Ex: to remove the elemwise inplace optimizer(slow for big graph)
use the flags: optimizer_excluding:inplace_opt inplace_opt is the name of that optimization.
Default: “”
A list of optimizer tags that we want included in the default Mode. If multiple tags, separate them by ‘:’.
Default: “”
A list of optimizer tags that we require for optimizer in the default Mode. If multiple tags, separate them by ‘:’.