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//CL//
/*
* Project: SILX: Alogorithms for image processing
*
* Copyright (C) 2013-2018 European Synchrotron Radiation Facility
* Grenoble, France
*
* Principal authors: J. Kieffer (kieffer@esrf.fr)
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/* Single kernel histogram for float array.
*
* Can perform histograming in log-scale (using the arcsinh)
Parameters:
- data: buffer with the image content in float (input)
- data_size: input
- mini: Lower bound of the first bin
- maxi: upper bouns of the last bin
- map_operation: Type of pre-processor to use. if if set to !=0, use log scale
- hist: resulting histogram (ouptut)
- hist_size: number of bins
- tmp_hist: temporary storage of size hist_size*num_groups
- processed: temporary storage of size 1 initialially set to 0
- local_hist: local storage of size hist_size
Grid information:
* use the largest WG size. If it is larger than the number of bins (hist_size),
take the power of 2 immediately above
*Schedule as many WG as the device has compute engines. No need to schuedule more,
it is just a waist of memory
* The histogram should fit in shared (local) memory and tmp_hist can be large!
Assumes:
hist and local_hist have size hist_size
edges has size hist_size+2
tmp_hist has size hist_size*num_groups
processed is of size one and initially set to 0
*/
static float preprocess(float value, int code)
{
//This function can be modified to have more scales
if (code!=0)
{
return asinh(value);
}
else
{
return value;
}
}
kernel void histogram(global float *data,
int data_size,
float mini,
float maxi,
int map_operation,
global int *hist,
global float *edges,
int hist_size,
global int *tmp_hist,
global int *processed,
local int *local_hist)
{
// each thread
int lid = get_local_id(0);
int ws = get_local_size(0);
int nb_engine = get_num_groups(0);
int engine_id = get_group_id(0);
// memset the local_hist array
for (int i=0; i<hist_size; i+=ws)
{
int j = i + lid;
if (j<hist_size)
{
local_hist[j] = 0;
}
}
barrier(CLK_LOCAL_MEM_FENCE);
// Process the local data and accumulate in shared memory
int bloc_size = (int) ceil((float)data_size/(float)nb_engine);
int start = bloc_size * engine_id;
int stop = min(start + bloc_size, data_size);
float vmini = preprocess(mini, map_operation);
float vscale = (float)hist_size/(preprocess(maxi, map_operation) -vmini);
for (int i = start; i<stop; i+=ws)
{
int address = i + lid;
if (address < stop)
{
float value = data[address];
if ((!isnan(value)) && (value>=mini) && (value<=maxi))
{
float vvalue = (preprocess(value, map_operation)-vmini)*vscale;
int idx = clamp((int) vvalue, 0, hist_size - 1);
atomic_inc(&local_hist[idx]);
}
}
}
barrier(CLK_LOCAL_MEM_FENCE);
//Now copy result into the right place and reset the first value of the shared array
for (int i=0; i<hist_size; i+=ws)
{
int j = i + lid;
if (j<hist_size)
{
tmp_hist[hist_size * engine_id + j] = local_hist[j];
}
}
barrier(CLK_LOCAL_MEM_FENCE);
local_hist[0] = 0;
barrier(CLK_LOCAL_MEM_FENCE);
//Increment the system wide shared variable processed and share the result with the workgroup
if (lid == 0)
{
local_hist[0] = atomic_inc(processed);
}
barrier(CLK_LOCAL_MEM_FENCE);
// If we are the engine last to work, perform the concatenation of all results
if ((local_hist[0] + 1) == nb_engine)
{
for (int i=0; i<hist_size; i+=ws)
{
int j = i + lid;
int lsum = 0;
if (j<hist_size)
{
for (int k=0; k<nb_engine; k++)
{
lsum += tmp_hist[hist_size * k + j];
}
hist[j] = lsum;
edges[j] = vmini + j/vscale;
}
}
// Finally reset the counter
if (lid == 0)
{
processed[0] = 0;
edges[hist_size] = vmini + hist_size/vscale;;
}
}
}
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