| 1 | ************************************************************************* | 
| 2 | * | 
| 3 | *     Subroutine inter_B_outer.f | 
| 4 | * | 
| 5 | *     it computes the magnetic field in a chosen point x,y,z OUTSIDE 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 the outer map | 
| 9 | * | 
| 10 | *     needs: | 
| 11 | *     - ../common/common_B_outer.f | 
| 12 | * | 
| 13 | *     input: coordinates in m | 
| 14 | *     output: magnetic field in T | 
| 15 | * | 
| 16 | ************************************************************************* | 
| 17 |  | 
| 18 | subroutine inter_B_outer(x,y,z,res) !coordinates in m, magnetic field in T | 
| 19 |  | 
| 20 | IMPLICIT DOUBLE PRECISION (A-H,O-Z) | 
| 21 | #include "gpfield.inc" | 
| 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 zin | 
| 33 |  | 
| 34 | integer ic | 
| 35 | c     !index for B components: | 
| 36 | c     ! ic=1 ---> Bx | 
| 37 | c     ! ic=2 ---> By | 
| 38 | c     ! ic=3 ---> Bz | 
| 39 |  | 
| 40 | integer cube(3) | 
| 41 | c     !vector of indexes identifying the cube | 
| 42 | c     ! containing the point of interpolation | 
| 43 | c     ! (see later...) | 
| 44 |  | 
| 45 | real*8 xl,xh,yl,yh,zl,zh  !cube vertexes coordinates | 
| 46 |  | 
| 47 | real*8 xr,yr,zr | 
| 48 | c     !reduced variables (coordinates of the | 
| 49 | c     ! point of interpolation inside the cube) | 
| 50 |  | 
| 51 | real*8 Bp(8) | 
| 52 | c     !vector of values of B component | 
| 53 | c     ! being computed, on the eight cube vertexes | 
| 54 |  | 
| 55 |  | 
| 56 | c     LOWER MAP | 
| 57 | c     ---> up/down simmetry | 
| 58 | zin=z | 
| 59 | if(zin.le.edgelzmax)z=-z | 
| 60 |  | 
| 61 | c------------------------------------------------------------------------ | 
| 62 | c | 
| 63 | c     *** MAP *** | 
| 64 | c | 
| 65 | c------------------------------------------------------------------------ | 
| 66 |  | 
| 67 | do ic=1,3                 !loops on the three B components | 
| 68 |  | 
| 69 | c------------------------------------------------------------------------ | 
| 70 | c | 
| 71 | c     chooses the coordinates interval containing the input point | 
| 72 | c | 
| 73 | c------------------------------------------------------------------------ | 
| 74 | c     e.g.: | 
| 75 | c | 
| 76 | c     x1    x2    x3    x4    x5...               xN | 
| 77 | c     |-----|-+---|-----|-----|---- ... ----|-----| | 
| 78 | c     ~~~~~~~~x | 
| 79 | c | 
| 80 | c     in this case the right interval is identified by indexes 2-3, so the | 
| 81 | c     value assigned to cube variable is 2 | 
| 82 |  | 
| 83 | cube(1)=INT((nox-1)*(x-poxmin(ic))/(poxmax(ic)-poxmin(ic))) +1 | 
| 84 | cube(2)=INT((noy-1)*(y-poymin(ic))/(poymax(ic)-poymin(ic))) +1 | 
| 85 | cube(3)=INT((noz-1)*(z-pozmin(ic))/(pozmax(ic)-pozmin(ic))) +1 | 
| 86 |  | 
| 87 | c------------------------------------------------------------------------ | 
| 88 | c | 
| 89 | c     if the point falls beyond the extremes of the grid... | 
| 90 | c | 
| 91 | c------------------------------------------------------------------------ | 
| 92 | c | 
| 93 | c     ~~~~~~~~~~x1    x2    x3... | 
| 94 | c     - - + - - |-----|-----|---- | 
| 95 | c     ~~~~x | 
| 96 | c | 
| 97 | c     in the case cube = 1 | 
| 98 | c | 
| 99 | c | 
| 100 | c     ...nx-2  nx-1  nx | 
| 101 | c     ----|-----|-----| - - - + - - | 
| 102 | c     ~~~~~~~~~~~~~~~~~~~~~~~~x | 
| 103 | c | 
| 104 | c     in this case cube = nx-1 | 
| 105 |  | 
| 106 | if (cube(1).le.0) cube(1) = 1 | 
| 107 | if (cube(2).le.0) cube(2) = 1 | 
| 108 | if (cube(3).le.0) cube(3) = 1 | 
| 109 | if (cube(1).ge.nox) cube(1) = nox-1 | 
| 110 | if (cube(2).ge.noy) cube(2) = noy-1 | 
| 111 | if (cube(3).ge.noz) cube(3) = noz-1 | 
| 112 |  | 
| 113 |  | 
| 114 | c------------------------------------------------------------------------ | 
| 115 | c | 
| 116 | c     temporary variables definition for field computation | 
| 117 | c | 
| 118 | c------------------------------------------------------------------------ | 
| 119 |  | 
| 120 | xl = pox(cube(1),ic)    !X coordinates of cube vertexes | 
| 121 | xh = pox(cube(1)+1,ic) | 
| 122 |  | 
| 123 | yl = poy(cube(2),ic)    !Y coordinates of cube vertexes | 
| 124 | yh = poy(cube(2)+1,ic) | 
| 125 |  | 
| 126 | zl = poz(cube(3),ic)    !Z coordinates of cube vertexes | 
| 127 | zh = poz(cube(3)+1,ic) | 
| 128 |  | 
| 129 | xr = (x-xl) / (xh-xl)   !reduced variables | 
| 130 | yr = (y-yl) / (yh-yl) | 
| 131 | zr = (z-zl) / (zh-zl) | 
| 132 |  | 
| 133 | Bp(1) = bo(cube(1)  ,cube(2)  ,cube(3)  ,ic) !ic-th component of B | 
| 134 | Bp(2) = bo(cube(1)+1,cube(2)  ,cube(3)  ,ic) ! on the eight cube | 
| 135 | Bp(3) = bo(cube(1)  ,cube(2)+1,cube(3)  ,ic) ! vertexes | 
| 136 | Bp(4) = bo(cube(1)+1,cube(2)+1,cube(3)  ,ic) | 
| 137 | Bp(5) = bo(cube(1)  ,cube(2)  ,cube(3)+1,ic) | 
| 138 | Bp(6) = bo(cube(1)+1,cube(2)  ,cube(3)+1,ic) | 
| 139 | Bp(7) = bo(cube(1)  ,cube(2)+1,cube(3)+1,ic) | 
| 140 | Bp(8) = bo(cube(1)+1,cube(2)+1,cube(3)+1,ic) | 
| 141 |  | 
| 142 | c------------------------------------------------------------------------ | 
| 143 | c | 
| 144 | c     computes interpolated ic-th component of B in (x,y,z) | 
| 145 | c | 
| 146 | c------------------------------------------------------------------------ | 
| 147 |  | 
| 148 | res(ic) = | 
| 149 | +       Bp(1)*(1-xr)*(1-yr)*(1-zr) + | 
| 150 | +       Bp(2)*xr*(1-yr)*(1-zr) + | 
| 151 | +       Bp(3)*(1-xr)*yr*(1-zr) + | 
| 152 | +       Bp(4)*xr*yr*(1-zr) + | 
| 153 | +       Bp(5)*(1-xr)*(1-yr)*zr + | 
| 154 | +       Bp(6)*xr*(1-yr)*zr + | 
| 155 | +       Bp(7)*(1-xr)*yr*zr + | 
| 156 | +       Bp(8)*xr*yr*zr | 
| 157 |  | 
| 158 |  | 
| 159 | enddo | 
| 160 |  | 
| 161 | c     LOWER MAP | 
| 162 | c     ---> up/down simmetry | 
| 163 | if(zin.le.edgelzmax)then | 
| 164 | z=-z                   !back to initial ccoordinate | 
| 165 | res(3)=-res(3)         !invert BZ component | 
| 166 | endif | 
| 167 |  | 
| 168 | return | 
| 169 | end |