iamin

Finds the index of the element with the smallest absolute value.

Description

The iamin routines return an index i such that x[i] has the minimum absolute value of all elements in vector x (real variants), or such that (|Re(x[i])| + |Im(x[i])|) is minimal (complex variants).

The index is zero-based if base is set to oneapi::math::index_base::zero (default) or one-based if it is set to oneapi::math::index_base::one.

If either n or incx is not positive, the routine returns 0, regardless of the base of the index selected.

If more than one vector element is found with the same smallest absolute value, the index of the first one encountered is returned.

If the vector contains NaN values, then the routine returns the index of the first NaN.

iamin supports the following precisions.

T
float
double
std::complex<float>
std::complex<double>

iamin (Buffer Version)

Syntax

namespace oneapi::math::blas::column_major {
    void iamin(sycl::queue &queue,
               std::int64_t n,
               sycl::buffer<T,1> &x,
               std::int64_t incx,
               sycl::buffer<std::int64_t,1> &result,
               oneapi::math::index_base base = oneapi::math::index_base::zero)
}

namespace oneapi::math::blas::row_major {
    void iamin(sycl::queue &queue,
               std::int64_t n,
               sycl::buffer<T,1> &x,
               std::int64_t incx,
               sycl::buffer<std::int64_t,1> &result,
               oneapi::math::index_base base = oneapi::math::index_base::zero)
}

Input Parameters

queue

The queue where the routine should be executed.

n

Number of elements in vector x.

x

Buffer holding input vector x. The buffer must be of size at least (1 + (n - 1)*abs(incx)). See Matrix Storage for more details.

incx

Stride of vector x.

base

Indicates how the output value is indexed. If omitted, defaults to zero-based indexing.

Output Parameters

result

Buffer where the index i of the minimum element will be stored.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::math::invalid_argument

oneapi::math::unsupported_device

oneapi::math::host_bad_alloc

oneapi::math::device_bad_alloc

oneapi::math::unimplemented

iamin (USM Version)

Syntax

namespace oneapi::math::blas::column_major {
    sycl::event iamin(sycl::queue &queue,
                      std::int64_t n,
                      const T *x,
                      std::int64_t incx,
                      std::int64_t *result,
                      oneapi::math::index_base base = oneapi::math::index_base::zero,
                      const std::vector<sycl::event> &dependencies = {})
}

namespace oneapi::math::blas::row_major {
    sycl::event iamin(sycl::queue &queue,
                      std::int64_t n,
                      const T *x,
                      std::int64_t incx,
                      std::int64_t *result,
                      oneapi::math::index_base base = oneapi::math::index_base::zero,
                      const std::vector<sycl::event> &dependencies = {})
}

Input Parameters

queue

The queue where the routine should be executed.

n

Number of elements in vector x.

x

The pointer to input vector x. The array holding input vector x must be of size at least (1 + (n - 1)*abs(incx)). See Matrix Storage for more details.

incx

Stride of vector x.

base

Indicates how the output value is indexed. If omitted, defaults to zero-based indexing.

dependencies

List of events to wait for before starting computation, if any. If omitted, defaults to no dependencies.

Output Parameters

result

Pointer to where the index i of the minimum element will be stored.

Return Values

Output event to wait on to ensure computation is complete.

Throws

This routine shall throw the following exceptions if the associated condition is detected. An implementation may throw additional implementation-specific exception(s) in case of error conditions not covered here.

oneapi::math::invalid_argument

oneapi::math::unsupported_device

oneapi::math::host_bad_alloc

oneapi::math::device_bad_alloc

oneapi::math::unimplemented

Parent topic: BLAS Level 1 Routines