Device Class

2.1 Basic Information

• Class: HEaaN::Device

• Purpose: Unified management of CPU and GPU devices

2.2 API Reference

2.2.1 Constructors

Device(DeviceType type)
Device(DeviceType type, int device_id)

• Function: Creates a device object

• Usage Example:

//Create CPU device (uses CPU device)
Device cpu_device(DeviceType::CPU);

// Create GPU device (uses currently active GPU)
Device gpu_device(DeviceType::GPU);

//Create specific GPU device
Device sepcific_gpu(DeviceType::GPU, 1); // Use GPU 1

device_id is only allowed to use 0.

2.2.2 Device Information Retrieval

DeviceType type() const
int id() const

• Function: Retrieves device type and ID

• Usage Example:

Device device(DeviceType::GPU);
if(device.type() == DeviceType::GPU) {
    int gpuId = device.id();
}

2.2.3 Device Comparison

bool operator==(const Device &other) const
bool operator!=(const Device &other) const
bool operator<(const Device &other) const

• Function: Device object comparison

• Usage Example:

Device device1(DeviceType::GPU, 0);
Device device2(DeviceType::GPU, 1);
if(device1 != device2) {
    // Different devices
}

2.3 Utility Functions

2.3.1 Default Device

Device getDefaultDevice()

• Function: Returns the default CPU device.

• Return Value: Device object of CPU type

2.3.2 CUDA Device Management

Device getCurrentCudaDevice()
void setCurrentCudaDevice(int device_id)

• Functions: Retrieves and sets the current CUDA device

• Usage Example:

HEaaN::setCurrentCudaDevice(0);
Device currentDevice = HEaaN::getCurrentDevice();

2.4 ScopedCudaDeviceSelector

This class is used when allocating memory for different devices in a multi-GPU environment.

Within a specific scope, it stores the previous device, sets a new device, and then reverts back to the previous device when exiting that scope.