Initalization and Information

gpu::getCudaEnabledDeviceCount

Returns the number of installed CUDA-enabled devices.

C++: int gpu::getCudaEnabledDeviceCount()

Use this function before any other GPU functions calls. If OpenCV is compiled without GPU support, this function returns 0.

gpu::setDevice

Sets a device and initializes it for the current thread.

C++: void gpu::setDevice(int device)

Parameters:

• device – System index of a GPU device starting with 0.

If the call of this function is omitted, a default device is initialized at the fist GPU usage.

gpu::getDevice

Returns the current device index set by gpu::setDevice() or initialized by default.

C++: int gpu::getDevice()

gpu::resetDevice

Explicitly destroys and cleans up all resources associated with the current device in the current process.

C++: void gpu::resetDevice()

Any subsequent API call to this device will reinitialize the device.

gpu::FeatureSet

Enumeration providing GPU computing features.

enum FeatureSet
{
    FEATURE_SET_COMPUTE_10,
    FEATURE_SET_COMPUTE_11,
    FEATURE_SET_COMPUTE_12,
    FEATURE_SET_COMPUTE_13,
    FEATURE_SET_COMPUTE_20,
    FEATURE_SET_COMPUTE_21,
    GLOBAL_ATOMICS,
    SHARED_ATOMICS,
    NATIVE_DOUBLE
};

gpu::TargetArchs

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:

C++: static bool gpu::TargetArchs::builtWith(FeatureSet feature_set)

Parameters:

• feature_set – Features to be checked. See gpu::FeatureSet.

There is a set of methods to check whether the module contains intermediate (PTX) or binary GPU code for the given architecture(s):

C++: static bool gpu::TargetArchs::has(int major, int minor)

C++: static bool gpu::TargetArchs::hasPtx(int major, int minor)

C++: static bool gpu::TargetArchs::hasBin(int major, int minor)

C++: static bool gpu::TargetArchs::hasEqualOrLessPtx(int major, int minor)

C++: static bool gpu::TargetArchs::hasEqualOrGreater(int major, int minor)

C++: static bool gpu::TargetArchs::hasEqualOrGreaterPtx(int major, int minor)

C++: static bool gpu::TargetArchs::hasEqualOrGreaterBin(int major, int minor)

Parameters:

• major – Major compute capability version.
• 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”.

gpu::DeviceInfo

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(FeatureSet feature) const;
    bool isCompatible() const;

    int deviceID() const;
};

gpu::DeviceInfo::DeviceInfo

The constructors.

C++: gpu::DeviceInfo::DeviceInfo()

C++: gpu::DeviceInfo::DeviceInfo(int device_id)

Parameters:

• device_id – System index of the GPU device starting with 0.

Constructs the DeviceInfo object for the specified device. If device_id parameter is missed, it constructs an object for the current device.

gpu::DeviceInfo::name

Returns the device name.

C++: string gpu::DeviceInfo::name() const

gpu::DeviceInfo::majorVersion

Returns the major compute capability version.

C++: int gpu::DeviceInfo::majorVersion()

gpu::DeviceInfo::minorVersion

Returns the minor compute capability version.

C++: int gpu::DeviceInfo::minorVersion()

gpu::DeviceInfo::multiProcessorCount

Returns the number of streaming multiprocessors.

C++: int gpu::DeviceInfo::multiProcessorCount()

gpu::DeviceInfo::freeMemory

Returns the amount of free memory in bytes.

C++: size_t gpu::DeviceInfo::freeMemory()

gpu::DeviceInfo::totalMemory

Returns the amount of total memory in bytes.

C++: size_t gpu::DeviceInfo::totalMemory()

gpu::DeviceInfo::supports

Provides information on GPU feature support.

C++: bool gpu::DeviceInfo::supports(FeatureSet feature_set) const

Parameters:

• feature_set – Features to be checked. See gpu::FeatureSet.

This function returns true if the device has the specified GPU feature. Otherwise, it returns false .

gpu::DeviceInfo::isCompatible

Checks the GPU module and device compatibility.

C++: bool gpu::DeviceInfo::isCompatible()

This function returns true if the GPU module can be run on the specified device. Otherwise, it returns false .

gpu::DeviceInfo::deviceID

Returns system index of the GPU device starting with 0.

C++: int gpu::DeviceInfo::deviceID()