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/*
* Project: silx: filtered backprojection
*
* Copyright (C) 2016-2017 European Synchrotron Radiation Facility
* Grenoble, France
*
* Principal authors: A. Mirone
* P. Paleo
*
*
* 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.
*/
/*******************************************************************************/
/************************ GPU VERSION (with textures) **************************/
/*******************************************************************************/
#ifndef DONT_USE_TEXTURES
kernel void backproj_kernel(
int num_proj,
int num_bins,
float axis_position,
global float *d_SLICE,
read_only image2d_t d_sino,
float gpu_offset_x,
float gpu_offset_y,
global float * d_cos_s, // precalculated cos(theta[i])
global float* d_sin_s, // precalculated sin(theta[i])
global float* d_axis_s, // array of axis positions (n_projs)
local float* shared2) // 768B of local mem
{
const sampler_t sampler = CLK_NORMALIZED_COORDS_FALSE | CLK_ADDRESS_CLAMP_TO_EDGE | CLK_FILTER_LINEAR;
const int tidx = get_local_id(0); //threadIdx.x;
const int bidx = get_group_id(0); //blockIdx.x;
const int tidy = get_local_id(1); //threadIdx.y;
const int bidy = get_group_id(1); //blockIdx.y;
local float sh_cos[256];
local float sh_sin[256];
local float sh_axis[256];
float pcos, psin;
float h0, h1, h2, h3;
const float apos_off_x= gpu_offset_x - axis_position ;
const float apos_off_y= gpu_offset_y - axis_position ;
float acorr05;
float res0 = 0, res1 = 0, res2 = 0, res3 = 0;
const float bx00 = (32 * bidx + 2 * tidx + 0 + apos_off_x ) ;
const float by00 = (32 * bidy + 2 * tidy + 0 + apos_off_y ) ;
int read=0;
for(int proj=0; proj<num_proj; proj++) {
if(proj>=read) {
barrier(CLK_LOCAL_MEM_FENCE);
int ip = tidy*16+tidx;
if( read+ip < num_proj) {
sh_cos [ip] = d_cos_s[read+ip] ;
sh_sin [ip] = d_sin_s[read+ip] ;
sh_axis[ip] = d_axis_s[read+ip] ;
}
read=read+256; // 256=16*16 block size
barrier(CLK_LOCAL_MEM_FENCE);
}
pcos = sh_cos[256-read + proj] ;
psin = sh_sin[256-read + proj] ;
acorr05 = sh_axis[256 - read + proj] ;
h0 = (acorr05 + bx00*pcos - by00*psin);
h1 = (acorr05 + (bx00+0)*pcos - (by00+1)*psin);
h2 = (acorr05 + (bx00+1)*pcos - (by00+0)*psin);
h3 = (acorr05 + (bx00+1)*pcos - (by00+1)*psin);
if(h0>=0 && h0<num_bins) res0 += read_imagef(d_sino, sampler, (float2) (h0 +0.5f,proj +0.5f)).x; // tex2D(texprojs,h0 +0.5f,proj +0.5f);
if(h1>=0 && h1<num_bins) res1 += read_imagef(d_sino, sampler, (float2) (h1 +0.5f,proj +0.5f)).x; // tex2D(texprojs,h1 +0.5f,proj +0.5f);
if(h2>=0 && h2<num_bins) res2 += read_imagef(d_sino, sampler, (float2) (h2 +0.5f,proj +0.5f)).x; // tex2D(texprojs,h2 +0.5f,proj +0.5f);
if(h3>=0 && h3<num_bins) res3 += read_imagef(d_sino, sampler, (float2) (h3 +0.5f,proj +0.5f)).x; // tex2D(texprojs,h3 +0.5f,proj +0.5f);
}
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+0) + bidx*32 + tidx*2 + 0] = res0;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+1) + bidx*32 + tidx*2 + 0] = res1;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+0) + bidx*32 + tidx*2 + 1] = res2;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+1) + bidx*32 + tidx*2 + 1] = res3;
}
#endif
/*******************************************************************************/
/********************* CPU VERSION (without textures) **************************/
/*******************************************************************************/
#define CLIP_MAX(x, N) (fmin(fmax(x, 0.0f), (N - 1.0f)))
#define FLOORCEIL_x(x) {\
xm = (int) floor(x);\
xp = (int) ceil(x);\
}
#define ADJACENT_PIXELS_VALS(arr, Nx, y, xm, xp) ((float2) (arr[y*Nx+xm], arr[y*Nx+xp]))
//Simple linear interpolator for working on the GPU
static float linear_interpolation(float2 vals,
float x,
int xm,
int xp)
{
if (xm == xp)
return vals.s0;
else
return (vals.s0 * (xp - x)) + (vals.s1 * (x - xm));
}
/**
*
* Same kernel as backproj_kernel, but targets the CPU (no texture)
*
**/
kernel void backproj_cpu_kernel(
int num_proj,
int num_bins,
float axis_position,
global float *d_SLICE,
global float* d_sino,
float gpu_offset_x,
float gpu_offset_y,
global float * d_cos_s, // precalculated cos(theta[i])
global float * d_sin_s, // precalculated sin(theta[i])
global float * d_axis_s, // array of axis positions (n_projs)
local float* shared2) // 768B of local mem
{
const int tidx = get_local_id(0); //threadIdx.x;
const int bidx = get_group_id(0); //blockIdx.x;
const int tidy = get_local_id(1); //threadIdx.y;
const int bidy = get_group_id(1); //blockIdx.y;
local float sh_cos[256];
local float sh_sin[256];
local float sh_axis[256];
float pcos, psin;
float h0, h1, h2, h3;
const float apos_off_x= gpu_offset_x - axis_position ;
const float apos_off_y= gpu_offset_y - axis_position ;
float acorr05;
float res0 = 0, res1 = 0, res2 = 0, res3 = 0;
const float bx00 = (32 * bidx + 2 * tidx + 0 + apos_off_x ) ;
const float by00 = (32 * bidy + 2 * tidy + 0 + apos_off_y ) ;
int read=0;
for(int proj=0; proj<num_proj; proj++) {
if(proj>=read) {
barrier(CLK_LOCAL_MEM_FENCE);
int ip = tidy*16+tidx;
if( read+ip < num_proj) {
sh_cos [ip] = d_cos_s[read+ip] ;
sh_sin [ip] = d_sin_s[read+ip] ;
sh_axis[ip] = d_axis_s[read+ip] ;
}
read=read+256; // 256=16*16 block size
barrier(CLK_LOCAL_MEM_FENCE);
}
pcos = sh_cos[256-read + proj] ;
psin = sh_sin[256-read + proj] ;
acorr05 = sh_axis[256 - read + proj] ;
h0 = (acorr05 + bx00*pcos - by00*psin);
h1 = (acorr05 + (bx00+0)*pcos - (by00+1)*psin);
h2 = (acorr05 + (bx00+1)*pcos - (by00+0)*psin);
h3 = (acorr05 + (bx00+1)*pcos - (by00+1)*psin);
float x;
int ym, xm, xp;
ym = proj;
float2 vals;
if(h0>=0 && h0<num_bins) {
x = CLIP_MAX(h0, num_bins);
FLOORCEIL_x(x);
vals = ADJACENT_PIXELS_VALS(d_sino, num_bins, ym, xm, xp);
res0 += linear_interpolation(vals, x, xm, xp);
}
if(h1>=0 && h1<num_bins) {
x = CLIP_MAX(h1, num_bins);
FLOORCEIL_x(x);
vals = ADJACENT_PIXELS_VALS(d_sino, num_bins, ym, xm, xp);
res1 += linear_interpolation(vals, x, xm, xp);
}
if(h2>=0 && h2<num_bins) {
x = CLIP_MAX(h2, num_bins);
FLOORCEIL_x(x);
vals = ADJACENT_PIXELS_VALS(d_sino, num_bins, ym, xm, xp);
res2 += linear_interpolation(vals, x, xm, xp);
}
if(h3>=0 && h3<num_bins) {
x = CLIP_MAX(h3, num_bins);
FLOORCEIL_x(x);
vals = ADJACENT_PIXELS_VALS(d_sino, num_bins, ym, xm, xp);
res3 += linear_interpolation(vals, x, xm, xp);
}
}
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+0) + bidx*32 + tidx*2 + 0] = res0;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+1) + bidx*32 + tidx*2 + 0] = res1;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+0) + bidx*32 + tidx*2 + 1] = res2;
d_SLICE[ 32*get_num_groups(0)*(bidy*32+tidy*2+1) + bidx*32 + tidx*2 + 1] = res3;
}
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