opencv/modules/gpu/doc/initalization_and_information.rst

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Initalization and Information
=============================
.. highlight:: cpp
.. index:: gpu::getCudaEnabledDeviceCount
gpu::getCudaEnabledDeviceCount
----------------------------------
.. ocv:function:: int getCudaEnabledDeviceCount()
Returns the number of installed CUDA-enabled devices. Use this function before any other GPU functions calls. If OpenCV is compiled without GPU support, this function returns 0.
.. index:: gpu::setDevice
gpu::setDevice
------------------
.. ocv:function:: void setDevice(int device)
Sets a device and initializes it for the current thread. If the call of this function is omitted, a default device is initialized at the fist GPU usage.
:param device: System index of a GPU device starting with 0.
.. index:: gpu::getDevice
gpu::getDevice
------------------
.. ocv:function:: int getDevice()
Returns the current device index set by ``{gpu::getDevice}`` or initialized by default.
.. index:: gpu::GpuFeature
gpu::GpuFeature
---------------
.. ocv:class:: gpu::GpuFeature
Class providing GPU computing features.
::
enum GpuFeature
{
COMPUTE_10, COMPUTE_11,
COMPUTE_12, COMPUTE_13,
COMPUTE_20, COMPUTE_21,
ATOMICS, NATIVE_DOUBLE
};
.. index:: gpu::DeviceInfo
gpu::DeviceInfo
---------------
.. ocv:class:: gpu::DeviceInfo
Class providing functionality for querying the specified GPU properties.
::
class CV_EXPORTS DeviceInfo
{
public:
DeviceInfo();
DeviceInfo(int device_id);
string name() const;
int majorVersion() const;
int minorVersion() const;
int multiProcessorCount() const;
size_t freeMemory() const;
size_t totalMemory() const;
bool supports(GpuFeature feature) const;
bool isCompatible() const;
};
.. index:: gpu::DeviceInfo::DeviceInfo
.. Comment: two lines below look like a bug
gpu::DeviceInfo::DeviceInfo
-------------------------------
.. ocv:function:: gpu::DeviceInfo::DeviceInfo()
.. ocv:function:: gpu::DeviceInfo::DeviceInfo(int device_id)
Constructs the ``DeviceInfo`` object for the specified device. If ``device_id`` parameter is missed, it constructs an object for the current device.
:param device_id: System index of the GPU device starting with 0.
.. index:: gpu::DeviceInfo::name
gpu::DeviceInfo::name
-------------------------
.. ocv:function:: string gpu::DeviceInfo::name()
Returns the device name.
.. index:: gpu::DeviceInfo::majorVersion
gpu::DeviceInfo::majorVersion
---------------------------------
.. ocv:function:: int gpu::DeviceInfo::majorVersion()
Returns the major compute capability version.
.. index:: gpu::DeviceInfo::minorVersion
gpu::DeviceInfo::minorVersion
---------------------------------
.. ocv:function:: int gpu::DeviceInfo::minorVersion()
Returns the minor compute capability version.
.. index:: gpu::DeviceInfo::multiProcessorCount
gpu::DeviceInfo::multiProcessorCount
----------------------------------------
.. ocv:function:: int gpu::DeviceInfo::multiProcessorCount()
Returns the number of streaming multiprocessors.
.. index:: gpu::DeviceInfo::freeMemory
gpu::DeviceInfo::freeMemory
-------------------------------
.. ocv:function:: size_t gpu::DeviceInfo::freeMemory()
Returns the amount of free memory in bytes.
.. index:: gpu::DeviceInfo::totalMemory
gpu::DeviceInfo::totalMemory
--------------------------------
.. ocv:function:: size_t gpu::DeviceInfo::totalMemory()
Returns the amount of total memory in bytes.
.. index:: gpu::DeviceInfo::supports
gpu::DeviceInfo::supports
-----------------------------
.. ocv:function:: bool gpu::DeviceInfo::supports(GpuFeature feature)
Provides information on GPU feature support. This function returns true if the device has the specified GPU feature. Otherwise, it returns false.
:param feature: Feature to be checked. See :ocv:class:`gpu::GpuFeature`.
.. index:: gpu::DeviceInfo::isCompatible
gpu::DeviceInfo::isCompatible
---------------------------------
.. ocv:function:: bool gpu::DeviceInfo::isCompatible()
Checks the GPU module and device compatibility. This function returns ``true`` if the GPU module can be run on the specified device. Otherwise, it returns false.
.. index:: gpu::TargetArchs
gpu::TargetArchs
----------------
.. ocv:class:: gpu::TargetArchs
Class providing a set of static methods to check what NVIDIA* card architecture the GPU module was built for.
The following method checks whether the module was built with the support of the given feature:
.. ocv:function:: static bool gpu::TargetArchs::builtWith(GpuFeature feature)
:param feature: Feature to be checked. See :ocv:class:`gpu::GpuFeature`.
There is a set of methods to check whether the module contains intermediate (PTX) or binary GPU code for the given architecture(s):
.. ocv:function:: static bool gpu::TargetArchs::has(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasPtx(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasBin(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasEqualOrLessPtx(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasEqualOrGreater(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasEqualOrGreaterPtx(int major, int minor)
.. ocv:function:: static bool gpu::TargetArchs::hasEqualOrGreaterBin(int major, int minor)
:param major: Major compute capability version.
:param minor: Minor compute capability version.
According to the CUDA C Programming Guide Version 3.2: "PTX code produced for some specific compute capability can always be compiled to binary code of greater or equal compute capability".