Finds the index of the element with the largest absolute value in a vector.
void iamax(queue &exec_queue, std::int64_t n, buffer<T, 1> &x, std::int64_t incx, buffer<std::int64_t, 1> &result);
iamax supports the following precisions and devices:
T | Devices Supported |
---|---|
float | Host, CPU, and GPU |
double | Host, CPU, and GPU |
std::complex<float> | Host, CPU, and GPU |
std:complex<double> | Host, CPU, and GPU |
The iamax routines return an index i such that x[i] has the maximum absolute value of all elements in vector x (real variants), or such that |Re(x[i])| + |Im(x[i])| is maximal (complex variants).
If either n or incx are not positive, the routine returns 0.
If more than one vector element is found with the same largest 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.
The queue where the routine should be executed.
The number of elements in vector x.
The buffer that holds the input vector x. The buffer must be of size at least (1 + (n - 1)*abs(incx)). See Matrix and Vector Storage for more details.
The stride of vector x.
The buffer where the zero-based index i of the maximal element is stored.
An example of how to use iamaxcan be found in the Intel® oneMKL installation directory, under:
examples/sycl/blas/iamax.cpp