1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
|
/*******************************************************************************
*
* McStas, neutron ray-tracing package
* Copyright 1997-2006, All rights reserved
* Risoe National Laboratory, Roskilde, Denmark
* Institut Laue Langevin, Grenoble, France
*
* Component: MeanPollambda_monitor
*
* %I
* Written by: Peter Christiansen
* Date: July 2006
* Origin: Risoe
*
* Polarisation and wavelength sensitive monitor.
*
* %D A square single monitor that measures the MEAN projection of the
* polarisation along a given normalized m-vector (mx, my, mz) as a
* function of wavelength.
*
* Example: MeanPollambda_monitor(xwidth=0.1, yheight=0.1, npol=11, my=1, filename="meanpollambdaMon.data")
*
* %P
* INPUT PARAMETERS:
*
* xwidth: [m] Width of detector
* yheight: [m] Height of detector
* mx: [1] X-component of monitor vector (can be negative)
* my: [1] Y-component of monitor vector (can be negative)
* mz: [1] Z-component of monitor vector (can be negative)
* nL: [1] Number of bins in wavelength
* Lmin: [AA] Minimum wavelength detected
* Lmax: [AA] Maximum wavelength detected
* filename: [string] Name of file in which to store the data
* restore_neutron: [1] If set, the monitor does not influence the neutron state
* nowritefile: [1] If set, monitor will skip writing to disk
*
* CALCULATED PARAMETERS:
*
* PolL_N: [1] Array of neutron counts
* PolL_p: [1] Array of neutron weight counts
* PolL_p2: [1] Array of second moments
* HelpArray: [1] Array of weight counts used for normalization
*
* %E
*******************************************************************************/
DEFINE COMPONENT MeanPolLambda_monitor
SETTING PARAMETERS (xwidth=0.1, yheight=0.1, int nL=20, int restore_neutron=0, string filename=0, int nowritefile=0, mx=0, my=0, mz=0, Lmin, Lmax)
/* Neutron parameters: (x,y,z,vx,vy,vz,t,sx,sy,sz,p) */
DECLARE
%{
DArray1d PolL_N;
DArray1d PolL_p;
DArray1d PolL_p2;
DArray1d HelpArray;
%}
INITIALIZE
%{
// Check that input parameteters makes sense
if (Lmax<=Lmin) {
fprintf(stderr, "Pol_monitor: %s: l1 <= l0!\n"
"ERROR. Exiting",
NAME_CURRENT_COMP);
exit(1);
}
if (mx==0 && my==0 && mz==0) {
fprintf(stderr, "Pol_monitor: %s: NULL vector defined!\n"
"ERROR (mx, my, mz). Exiting",
NAME_CURRENT_COMP);
exit(1);
}
if ((xwidth<=0) || (yheight <= 0)) {
fprintf(stderr, "Pol_monitor: %s: Null detection area !\n"
"ERROR (xwidth,yheight). Exiting",
NAME_CURRENT_COMP);
exit(1);
}
// Initialize variables
NORM(mx, my, mz);
PolL_N = create_darr1d(nL);
PolL_p = create_darr1d(nL);
PolL_p2 = create_darr1d(nL);
HelpArray = create_darr1d(nL);
// Use instance name for monitor output if no input was given
if (!strcmp(filename,"\0")) sprintf(filename,"%s",NAME_CURRENT_COMP);
%}
TRACE
%{
int i;
double pol_proj;
double lambda;
PROP_Z0;
lambda = (2*PI/V2K)/sqrt(vx*vx + vy*vy + vz*vz);
if (inside_rectangle(x, y, xwidth, yheight) &&
lambda > Lmin && lambda < Lmax) {
pol_proj = scalar_prod(mx, my, mz, sx, sy, sz);
i= floor((lambda - Lmin)*nL/(Lmax - Lmin));
double p2 = p*p;
#pragma acc atomic
PolL_N[i] = PolL_N[i]+1;
#pragma acc atomic
HelpArray[i] = HelpArray[i] + p;
#pragma acc atomic
PolL_p[i] = PolL_p[i] + pol_proj*p;
#pragma acc atomic
PolL_p2[i] = PolL_p2[i] + pol_proj*pol_proj*p; /* Shouldn't this be p2?? */
SCATTER;
}
if (restore_neutron) {
RESTORE_NEUTRON(INDEX_CURRENT_COMP, x, y, z, vx, vy, vz, t, sx, sy, sz, p);
}
%}
SAVE
%{
if (!nowritefile) {
int i;
double mpifactor=1;
/*1st order correction: As polarisation is not an additive signal we should downweight by the node count.
This asssumes that all nodes have equal weight sum.*/
#ifdef USE_MPI
mpifactor=mpi_node_count;
#endif
// Average output
for (i=0; i<nL; i++) {
if(HelpArray[i] == 0)
continue;
PolL_p[i] /= HelpArray[i]*mpifactor;
// Mcstas uses the error sigma**2=sum p_i**2 for intensities
// But here we have the mean so the error**2 should be VAR/N:
// sigma**2 = [sum s_i*s_i*p_i/sum p_i - (sum s_i*p_i/sum p_i)**2]/N
PolL_p2[i] /= HelpArray[i]*mpifactor;
PolL_p2[i] -= PolL_p[i]*PolL_p[i];
PolL_p2[i] /= PolL_N[i];
}
DETECTOR_OUT_1D("Pol-wavelength monitor",
"Wavelength [AA]",
"Mean Polarisation",
"Wavelength", Lmin, Lmax, nL,
&PolL_N[0],&PolL_p[0],&PolL_p2[0],
filename);
}
%}
FINALLY
%{
destroy_darr1d(PolL_N);
destroy_darr1d(PolL_p);
destroy_darr1d(PolL_p2);
%}
MCDISPLAY
%{
rectangle("xy", 0, 0, 0, xwidth, yheight);
%}
END
|
