1 |
************************************************************************* |
2 |
* |
3 |
* Subroutine inter_B_inner.f |
4 |
* |
5 |
* it computes the magnetic field in a chosen point x,y,z inside the |
6 |
* magnetic cavity, using a trilinear interpolation of |
7 |
* B field measurements (read before by means of ./read_B.f) |
8 |
* the value is computed for two different inner maps and then averaged |
9 |
* |
10 |
* needs: |
11 |
* - ../common/common_B_inner.f |
12 |
* |
13 |
* input: coordinates in m |
14 |
* output: magnetic field in T |
15 |
* |
16 |
************************************************************************* |
17 |
|
18 |
subroutine inter_B_inner(x,y,z,res) !coordinates in m, magnetic field in T |
19 |
|
20 |
implicit double precision (a-h,o-z) |
21 |
include './common_B_inner.for' |
22 |
|
23 |
|
24 |
c------------------------------------------------------------------------ |
25 |
c |
26 |
c local variables |
27 |
c |
28 |
c------------------------------------------------------------------------ |
29 |
|
30 |
real*8 x,y,z !point of interpolation |
31 |
real*8 res(3) !interpolated B components: res = (Bx, By, Bz) |
32 |
real*8 res1(3),res2(3) !interpolated B components for the two maps |
33 |
|
34 |
integer ic !index for B components: |
35 |
! ic=1 ---> Bx |
36 |
! ic=2 ---> By |
37 |
! ic=3 ---> Bz |
38 |
|
39 |
integer cube(3) !vector of indexes identifying the cube |
40 |
! containing the point of interpolation |
41 |
! (see later...) |
42 |
|
43 |
real*8 xl,xh,yl,yh,zl,zh !cube vertexes coordinates |
44 |
|
45 |
real*8 xr,yr,zr !reduced variables (coordinates of the |
46 |
! point of interpolation inside the cube) |
47 |
|
48 |
real*8 Bp(8) !vector of values of B component |
49 |
! being computed, on the eight cube vertexes |
50 |
|
51 |
|
52 |
c------------------------------------------------------------------------ |
53 |
c |
54 |
c *** FIRST MAP *** |
55 |
c |
56 |
c------------------------------------------------------------------------ |
57 |
|
58 |
do ic=1,3 !loops on the three B components |
59 |
|
60 |
c------------------------------------------------------------------------ |
61 |
c |
62 |
c chooses the coordinates interval containing the input point |
63 |
c |
64 |
c------------------------------------------------------------------------ |
65 |
c e.g.: |
66 |
c |
67 |
c x1 x2 x3 x4 x5... |
68 |
c |-----|-+---|-----|-----|---- |
69 |
c ~~~~~~~~x |
70 |
c |
71 |
c in this case the right interval is identified by indexes 2-3, so the |
72 |
c value assigned to cube variable is 2 |
73 |
|
74 |
cube(1)=INT((nx-1)*(x-px1min(ic))/(px1max(ic)-px1min(ic))) +1 |
75 |
cube(2)=INT((ny-1)*(y-py1min(ic))/(py1max(ic)-py1min(ic))) +1 |
76 |
cube(3)=INT((nz-1)*(z-pz1min(ic))/(pz1max(ic)-pz1min(ic))) +1 |
77 |
|
78 |
c------------------------------------------------------------------------ |
79 |
c |
80 |
c if the point falls beyond the extremes of the grid... |
81 |
c |
82 |
c------------------------------------------------------------------------ |
83 |
c |
84 |
c ~~~~~~~~~~x1 x2 x3... |
85 |
c - - + - - |-----|-----|---- |
86 |
c ~~~~x |
87 |
c |
88 |
c in the case cube = 1 |
89 |
c |
90 |
c |
91 |
c ...nx-2 nx-1 nx |
92 |
c ----|-----|-----| - - - + - - |
93 |
c ~~~~~~~~~~~~~~~~~~~~~~~~x |
94 |
c |
95 |
c in this case cube = nx-1 |
96 |
|
97 |
if (cube(1).le.0) cube(1) = 1 |
98 |
if (cube(2).le.0) cube(2) = 1 |
99 |
if (cube(3).le.0) cube(3) = 1 |
100 |
if (cube(1).ge.nx) cube(1) = nx-1 |
101 |
if (cube(2).ge.ny) cube(2) = ny-1 |
102 |
if (cube(3).ge.nz) cube(3) = nz-1 |
103 |
|
104 |
|
105 |
c------------------------------------------------------------------------ |
106 |
c |
107 |
c temporary variables definition for field computation |
108 |
c |
109 |
c------------------------------------------------------------------------ |
110 |
|
111 |
xl = px1(cube(1),ic) !X coordinates of cube vertexes |
112 |
xh = px1(cube(1)+1,ic) |
113 |
|
114 |
yl = py1(cube(2),ic) !Y coordinates of cube vertexes |
115 |
yh = py1(cube(2)+1,ic) |
116 |
|
117 |
zl = pz1(cube(3),ic) !Z coordinates of cube vertexes |
118 |
zh = pz1(cube(3)+1,ic) |
119 |
|
120 |
xr = (x-xl) / (xh-xl) !reduced variables |
121 |
yr = (y-yl) / (yh-yl) |
122 |
zr = (z-zl) / (zh-zl) |
123 |
|
124 |
Bp(1) = b1(cube(1) ,cube(2) ,cube(3) ,ic) !ic-th component of B |
125 |
Bp(2) = b1(cube(1)+1,cube(2) ,cube(3) ,ic) ! on the eight cube |
126 |
Bp(3) = b1(cube(1) ,cube(2)+1,cube(3) ,ic) ! vertexes |
127 |
Bp(4) = b1(cube(1)+1,cube(2)+1,cube(3) ,ic) |
128 |
Bp(5) = b1(cube(1) ,cube(2) ,cube(3)+1,ic) |
129 |
Bp(6) = b1(cube(1)+1,cube(2) ,cube(3)+1,ic) |
130 |
Bp(7) = b1(cube(1) ,cube(2)+1,cube(3)+1,ic) |
131 |
Bp(8) = b1(cube(1)+1,cube(2)+1,cube(3)+1,ic) |
132 |
|
133 |
c------------------------------------------------------------------------ |
134 |
c |
135 |
c computes interpolated ic-th component of B in (x,y,z) |
136 |
c |
137 |
c------------------------------------------------------------------------ |
138 |
|
139 |
res1(ic) = |
140 |
+ Bp(1)*(1-xr)*(1-yr)*(1-zr) + |
141 |
+ Bp(2)*xr*(1-yr)*(1-zr) + |
142 |
+ Bp(3)*(1-xr)*yr*(1-zr) + |
143 |
+ Bp(4)*xr*yr*(1-zr) + |
144 |
+ Bp(5)*(1-xr)*(1-yr)*zr + |
145 |
+ Bp(6)*xr*(1-yr)*zr + |
146 |
+ Bp(7)*(1-xr)*yr*zr + |
147 |
+ Bp(8)*xr*yr*zr |
148 |
|
149 |
|
150 |
enddo |
151 |
|
152 |
c------------------------------------------------------------------------ |
153 |
c |
154 |
c *** SECOND MAP *** |
155 |
c |
156 |
c------------------------------------------------------------------------ |
157 |
|
158 |
c second map is rotated by 180 degree along the Z axis. so change sign |
159 |
c of x and y coordinates and then change sign to Bx and By components |
160 |
c to obtain the correct result |
161 |
|
162 |
x=-x |
163 |
y=-y |
164 |
|
165 |
do ic=1,3 |
166 |
|
167 |
cube(1)=INT((nx-1)*(x-px2min(ic))/(px2max(ic)-px2min(ic))) +1 |
168 |
cube(2)=INT((ny-1)*(y-py2min(ic))/(py2max(ic)-py2min(ic))) +1 |
169 |
cube(3)=INT((nz-1)*(z-pz2min(ic))/(pz2max(ic)-pz2min(ic))) +1 |
170 |
|
171 |
if (cube(1).le.0) cube(1) = 1 |
172 |
if (cube(2).le.0) cube(2) = 1 |
173 |
if (cube(3).le.0) cube(3) = 1 |
174 |
if (cube(1).ge.nx) cube(1) = nx-1 |
175 |
if (cube(2).ge.ny) cube(2) = ny-1 |
176 |
if (cube(3).ge.nz) cube(3) = nz-1 |
177 |
|
178 |
xl = px2(cube(1),ic) |
179 |
xh = px2(cube(1)+1,ic) |
180 |
|
181 |
yl = py2(cube(2),ic) |
182 |
yh = py2(cube(2)+1,ic) |
183 |
|
184 |
zl = pz2(cube(3),ic) |
185 |
zh = pz2(cube(3)+1,ic) |
186 |
|
187 |
xr = (x-xl) / (xh-xl) |
188 |
yr = (y-yl) / (yh-yl) |
189 |
zr = (z-zl) / (zh-zl) |
190 |
|
191 |
Bp(1) = b2(cube(1) ,cube(2) ,cube(3) ,ic) |
192 |
Bp(2) = b2(cube(1)+1,cube(2) ,cube(3) ,ic) |
193 |
Bp(3) = b2(cube(1) ,cube(2)+1,cube(3) ,ic) |
194 |
Bp(4) = b2(cube(1)+1,cube(2)+1,cube(3) ,ic) |
195 |
Bp(5) = b2(cube(1) ,cube(2) ,cube(3)+1,ic) |
196 |
Bp(6) = b2(cube(1)+1,cube(2) ,cube(3)+1,ic) |
197 |
Bp(7) = b2(cube(1) ,cube(2)+1,cube(3)+1,ic) |
198 |
Bp(8) = b2(cube(1)+1,cube(2)+1,cube(3)+1,ic) |
199 |
|
200 |
res2(ic) = |
201 |
+ Bp(1)*(1-xr)*(1-yr)*(1-zr) + |
202 |
+ Bp(2)*xr*(1-yr)*(1-zr) + |
203 |
+ Bp(3)*(1-xr)*yr*(1-zr) + |
204 |
+ Bp(4)*xr*yr*(1-zr) + |
205 |
+ Bp(5)*(1-xr)*(1-yr)*zr + |
206 |
+ Bp(6)*xr*(1-yr)*zr + |
207 |
+ Bp(7)*(1-xr)*yr*zr + |
208 |
+ Bp(8)*xr*yr*zr |
209 |
|
210 |
enddo |
211 |
|
212 |
c change Bx and By components sign |
213 |
res2(1)=-res2(1) |
214 |
res2(2)=-res2(2) |
215 |
|
216 |
c change back the x and y coordinate signs |
217 |
x=-x |
218 |
y=-y |
219 |
|
220 |
|
221 |
c------------------------------------------------------------------------ |
222 |
c |
223 |
c average the two maps results |
224 |
c |
225 |
c------------------------------------------------------------------------ |
226 |
|
227 |
do ic=1,3 |
228 |
res(ic)=(res1(ic)+res2(ic))/2 |
229 |
enddo |
230 |
|
231 |
|
232 |
return |
233 |
end |