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// =================================================================================================
// This file is part of the CLBlast project. The project is licensed under Apache Version 2.0. This
// project loosely follows the Google C++ styleguide and uses a tab-size of two spaces and a max-
// width of 100 characters per line.
//
// Author(s):
// Cedric Nugteren <www.cedricnugteren.nl>
//
// This file contains the Xscal kernel. It contains one fast vectorized version in case of unit
// strides (incx=1) and no offsets (offx=0). Another version is more general, but doesn't support
// vector data-types.
//
// This kernel uses the level-1 BLAS common tuning parameters.
//
// =================================================================================================
// Enables loading of this file using the C++ pre-processor's #include (C++11 standard raw string
// literal). Comment-out this line for syntax-highlighting when developing.
R"(
// =================================================================================================
// Full version of the kernel with offsets and strided accesses
__attribute__((reqd_work_group_size(WGS, 1, 1)))
__kernel void Xscal(const int n, const real alpha,
__global real* xgm, const int x_offset, const int x_inc) {
// Loops over the work that needs to be done (allows for an arbitrary number of threads)
#pragma unroll
for (int id = get_global_id(0); id<n; id += get_global_size(0)) {
real result;
Multiply(result, alpha, xgm[id*x_inc + x_offset]);
xgm[id*x_inc + x_offset] = result;
}
}
// =================================================================================================
// Faster version of the kernel without offsets and strided accesses. Also assumes that 'n' is
// dividable by 'VW', 'WGS' and 'WPT'.
__attribute__((reqd_work_group_size(WGS, 1, 1)))
__kernel void XscalFast(const int n, const real alpha,
__global realV* xgm) {
#pragma unroll
for (int w=0; w<WPT; ++w) {
const int id = w*get_global_size(0) + get_global_id(0);
realV result;
result = MultiplyVector(result, alpha, xgm[id]);
xgm[id] = result;
}
}
// =================================================================================================
// End of the C++11 raw string literal
)"
// =================================================================================================
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