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/* ************************************************************************
* Copyright 2013 Advanced Micro Devices, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
* ************************************************************************/
static const char *iamax_kernel = "
#pragma OPENCL EXTENSION cl_amd_printf:enable
#ifdef DOUBLE_PRECISION
#ifdef cl_khr_fp64
#pragma OPENCL EXTENSION cl_khr_fp64 : enable
#else
#pragma OPENCL EXTENSION cl_amd_fp64 : enable
#endif
#define MIN 0x1.0p-1022 // Min in case of d/z (values from khronos site)
#else
#define MIN 0x1.0p-126f // Min in case od s/c
#endif
/******************************************************
* Implementations available for REDUCTION_BY_MAX
0 - ATOMIC_FLI
1 - REG_FLI,
2 - ATOMIC_FHI,
3 - REG_FHI
Implementation available for REDUCE_MAX
0 - FHI
1 - FLI
***************************************************/
__kernel void i%PREFIXamax_kernel( __global %TYPE *_X, __global %PTYPE *_scratchBuf,
uint N, uint offx, int incx)
{
__global %TYPE *X = _X + offx;
__global %PTYPE *scratchBufVal = _scratchBuf;
int numGrps = get_num_groups(0);
__global uint *scratchBufIndex = (__global uint*)(&_scratchBuf[numGrps]);
#ifdef RETURN_ON_INVALID
// Incase of incx<1, index will be zero
if( get_global_id(0) == 0 ) {
scratchBufVal[0] = (%PTYPE)0.0;
scratchBufIndex[0] = 0;
}
return;
#endif
%PTYPE maxVal = MIN, val = MIN;
uint index = 0, maxIndex = 0;
%TYPE%V vReg1;
%PTYPE%V pReg1;
int gOffset;
for( gOffset=(get_global_id(0) * %V); (gOffset + %V - 1)<N; gOffset+=( get_global_size(0) * %V ) )
{
#ifdef INCX_NONUNITY
%VLOADWITHINCX( vReg1, (X + (gOffset*incx)), incx);
#else
vReg1 = %VLOAD( 0, (X + (gOffset * incx)) );
#endif
pReg1 = %VABS(vReg1);
%REDUCE_MAX(pReg1,val,index,1); // Find max within a vector
if(val > maxVal)
{
maxVal = val;
maxIndex = (gOffset + index);
}
}
// Loop for the last thread to handle the tail part of the vector
// Using the same gOffset used above
for( ; gOffset<N; gOffset++ )
{
%TYPE sReg1;
sReg1 = X[gOffset * incx];
if(%VABS(sReg1) > maxVal)
{
maxVal = %VABS(sReg1);
maxIndex = gOffset;
}
}
// Note: this has to be called outside any if-conditions- because REDUCTION uses barrier
#ifdef REDUCE_MAX_WITH_INDEX_ATOMICS
%REDUCTION_BY_MAX(maxVal,maxIndex,0);
#else
%REDUCTION_BY_MAX(maxVal,maxIndex,1);
#endif
if(get_local_id(0) == 0)
{
scratchBufVal[get_group_id(0)] = maxVal;
scratchBufIndex[get_group_id(0)] = maxIndex + 1; // because 0 is reserved for error
}
}";
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