OpenCL Type Mapping#

Scalar Types#

For ease of use, a the cltypes module provides convenient mapping from OpenCL type names to their equivalent numpy types. This saves you from referring back to the OpenCL spec to see that a cl_long is 64 bit unsigned integer. Use the module as follows:

>>> import numpy as np
>>> import pyopencl as cl
>>> import pyopencl.cltypes
>>> cl_uint = cl.cltypes.uint(42)   # maps to numpy.uint32
>>> cl_long = cl.cltypes.long(1235) # maps to numpy.int64
>>> floats = np.empty((128,), dtype=cl.cltypes.float) # array of numpy.float32


The OpenCL type bool does not have a corresponding numpy type defined here, because OpenCL does not specify the in-memory representation (or even the storage size) for this type.

Vector Types#

The corresponding vector types are also made available in the same package, allowing you to easily create numpy arrays with the appropriate memory layout.

>>> import numpy as np
>>> array_of_float16 = np.empty((128,), dtype=cl.cltypes.float16) # array of float16