in_range#

Defined in the <cuda/utility> header.

namespace cuda {

template <typename T>
[[nodiscard]] __host__ __device__ constexpr
bool in_range(T value, T start, T end) noexcept;

} // namespace cuda

Checks whether a value value is within the range [start, end], inclusive.

Template Parameters

  • T: the type of the value and the range bounds.

Parameters

  • value: the value to check if it’s within the range.

  • start: the lower bound of the range.

  • end: the upper bound of the range.

Return Value

  • true if value is in the range [start, end], false otherwise.

Constraints

  • T must be an integer or floating point type.

Preconditions

  • end must be greater than or equal to start.

Note

For floating-point types, NaN is considered a valid value. The function returns false if any input is NaN.

Performance considerations

  • The function is optimized when value is an unsigned integer type. The optimization is useful when start and end are known at compile-time, or when in_range is used multiple times with the same range.

Example#

#include <cuda/utility>
#include <cuda/std/cassert>

__global__ void in_range_kernel() {
    // unsigned integers
    assert(cuda::in_range(5u, 1u, 10u));   // 5  is in the range     [1, 10]
    assert(!cuda::in_range(15u, 1u, 10u)); // 15 is NOT in the range [1, 10]
    assert(cuda::in_range(1u, 1u, 10u));   // 1  is in the range     [1, 10]
    assert(cuda::in_range(10u, 1u, 10u));  // 10 is in the range     [1, 10]
    assert(cuda::in_range(10u, 10u, 10u)); // 10 is in the range     [10, 10]

    // signed integers
    assert(cuda::in_range(-5, -10, 0));    // -5 is in the range    [-10, 0]
    assert(!cuda::in_range(5, -10, 0));    // 5 is NOT in the range [-10, 0]
}

int main() {
    in_range_kernel<<<1, 1>>>();
    cudaDeviceSynchronize();
    return 0;
}

See the example in Compiler Explorer 🔗

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