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#/*##########################################################################
# Copyright (c) 2004-2016 European Synchrotron Radiation Facility
#
# 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.
#
#############################################################################*/
/*
Implementation of the algorithm SNIP in 1D described in
Miroslav Morhac et al. Nucl. Instruments and Methods in Physics Research A401 (1997) 113-132.
The original idea for 1D and the low-statistics-digital-filter (lsdf) come from
C.G. Ryan et al. Nucl. Instruments and Methods in Physics Research B34 (1988) 396-402.
*/
#include <stdlib.h>
#include <string.h>
#include <math.h>
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#define MAX(x, y) (((x) > (y)) ? (x) : (y))
void lls(double *data, int size);
void lls_inv(double *data, int size);
void snip1d(double *data, int n_channels, int snip_width);
void snip1d_multiple(double *data, int n_channels, int snip_width, int n_spectra);
void lsdf(double *data, int size, int fwhm, double f, double A, double M, double ratio);
void lls(double *data, int size)
{
int i;
for (i=0; i< size; i++)
{
data[i] = log(log(sqrt(data[i]+1.0)+1.0)+1.0);
}
}
void lls_inv(double *data, int size)
{
int i;
double tmp;
for (i=0; i< size; i++)
{
/* slightly different than the published formula because
with the original formula:
tmp = exp(exp(data[i]-1.0)-1.0);
data[i] = tmp * tmp - 1.0;
one does not recover the original data */
tmp = exp(exp(data[i])-1.0)-1.0;
data[i] = tmp * tmp - 1.0;
}
}
void lsdf(double *data, int size, int fwhm, double f, double A, double M, double ratio)
{
int channel, i, j;
double L, R, S;
int width;
double dhelp;
width = (int) (f * fwhm);
for (channel=width; channel<(size-width); channel++)
{
i = width;
while(i>0)
{
L=0;
R=0;
for(j=channel-i; j<channel; j++)
{
L += data[j];
}
for(j=channel+1; j<channel+i; j++)
{
R += data[j];
}
S = data[channel] + L + R;
if (S<M)
{
data[channel] = S /(2*i+1);
break;
}
dhelp = (R+1)/(L+1);
if ((dhelp < ratio) && (dhelp > (1/ratio)))
{
if (S<(A*sqrt(data[channel])))
{
data[channel] = S /(2*i+1);
break;
}
}
i=i-1;
}
}
}
void snip1d(double *data, int n_channels, int snip_width)
{
snip1d_multiple(data, n_channels, snip_width, 1);
}
void snip1d_multiple(double *data, int n_channels, int snip_width, int n_spectra)
{
int i;
int j;
int p;
int offset;
double *w;
i = (int) (0.5 * snip_width);
/* lsdf(data, size, i, 1.5, 75., 10., 1.3); */
w = (double *) malloc(n_channels * sizeof(double));
for (j=0; j < n_spectra; j++)
{
offset = j * n_channels;
for (p = snip_width; p > 0; p--)
{
for (i=p; i<(n_channels - p); i++)
{
w[i] = MIN(data[i + offset], 0.5*(data[i + offset - p] + data[ i + offset + p]));
}
for (i=p; i<(n_channels - p); i++)
{
data[i+offset] = w[i];
}
}
}
free(w);
}
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