# hub.darcs.net :: basilisk -> basilisk -> files

Basilisk source code

## root / src / myc.h

 ```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 ``` ``````/*-----------------------------------------------------* *MYC - Mixed Youngs and Central Scheme * *-----------------------------------------------------*/ /* Known problems: the index [0,0,0], i.e. the central cell in the block, never occurs: neither in the central scheme nor in Youngs' method. Therefore an isolated droplet will have a normal with all components to zero. I took care of the division-by-zero issue, but not of this one. Ruben */ coord mycs (Point point, scalar c) { double m1,m2,m[4][3],t0,t1,t2; int cn; /* write the plane as: sgn(mx) X = my Y + mz Z + alpha m00 X = m01 Y + m02 Z + alpha */ m1 = c[-1,0,-1] + c[-1,0,1] + c[-1,-1,0] + c[-1,1,0] + c[-1,0,0]; m2 = c[1,0,-1] + c[1,0,1] + c[1,-1,0] + c[1,1,0] + c[1,0,0]; m[0][0] = m1 > m2 ? 1. : -1.; m1 = c[-1,-1,0]+ c[1,-1,0]+ c[0,-1,0]; m2 = c[-1,1,0]+ c[1,1,0]+ c[0,1,0]; m[0][1] = 0.5*(m1-m2); m1 = c[-1,0,-1]+ c[1,0,-1]+ c[0,0,-1]; m2 = c[-1,0,1]+ c[1,0,1]+ c[0,0,1]; m[0][2] = 0.5*(m1-m2); /* write the plane as: sgn(my) Y = mx X + mz Z + alpha m11 Y = m10 X + m12 Z + alpha */ m1 = c[-1,-1,0] + c[-1,1,0] + c[-1,0,0]; m2 = c[1,-1,0] + c[1,1,0] + c[1,0,0]; m[1][0] = 0.5*(m1-m2); m1 = c[0,-1,-1] + c[0,-1,1] + c[1,-1,0] + c[-1,-1,0] + c[0,-1,0]; m2 = c[0,1,-1] + c[0,1,1] + c[1,1,0] + c[-1,1,0] + c[0,1,0]; m[1][1] = m1 > m2 ? 1. : -1.; m1 = c[0,-1,-1]+ c[0,0,-1]+ c[0,1,-1]; m2 = c[0,-1,1]+ c[0,0,1]+ c[0,1,1]; m[1][2] = 0.5*(m1-m2); /* write the plane as: sgn(mz) Z = mx X + my Y + alpha m22 Z = m20 X + m21 Y + alpha */ m1 = c[-1,0,-1]+ c[-1,0,1]+ c[-1,0,0]; m2 = c[1,0,-1]+ c[1,0,1]+ c[1,0,0]; m[2][0] = 0.5*(m1-m2); m1 = c[0,-1,-1]+ c[0,-1,1]+ c[0,-1,0]; m2 = c[0,1,-1]+ c[0,1,1]+ c[0,1,0]; m[2][1] = 0.5*(m1-m2); m1 = c[-1,0,-1] + c[1,0,-1] + c[0,-1,-1] + c[0,1,-1] + c[0,0,-1]; m2 = c[-1,0,1] + c[1,0,1] + c[0,-1,1] + c[0,1,1] + c[0,0,1]; m[2][2] = m1 > m2 ? 1. : -1.; /* normalize each set (mx,my,mz): |mx|+|my|+|mz| = 1 */ t0 = fabs(m[0][0]) + fabs(m[0][1]) + fabs(m[0][2]); m[0][0] /= t0; m[0][1] /= t0; m[0][2] /= t0; t0 = fabs(m[1][0]) + fabs(m[1][1]) + fabs(m[1][2]); m[1][0] /= t0; m[1][1] /= t0; m[1][2] /= t0; t0 = fabs(m[2][0]) + fabs(m[2][1]) + fabs(m[2][2]); m[2][0] /= t0; m[2][1] /= t0; m[2][2] /= t0; /* choose among the three central scheme */ t0 = fabs(m[0][0]); t1 = fabs(m[1][1]); t2 = fabs(m[2][2]); cn = 0; if (t1 > t0) { t0 = t1; cn = 1; } if (t2 > t0) cn = 2; /* Youngs-CIAM scheme */ m1 = c[-1,-1,-1] + c[-1,1,-1] + c[-1,-1,1] + c[-1,1,1] + 2.*(c[-1,-1,0] + c[-1,1,0] + c[-1,0,-1] + c[-1,0,1]) + 4.*c[-1,0,0]; m2 = c[1,-1,-1] + c[1,1,-1] + c[1,-1,1] + c[1,1,1] + 2.*(c[1,-1,0] + c[1,1,0] + c[1,0,-1] + c[1,0,1]) + 4.*c[1,0,0]; m[3][0] = m1 - m2; m1 = c[-1,-1,-1] + c[-1,-1,1] + c[1,-1,-1] + c[1,-1,1] + 2.*( c[-1,-1,0] + c[1,-1,0] + c[0,-1,-1] + c[0,-1,1]) + 4.*c[0,-1,0]; m2 = c[-1,1,-1] + c[-1,1,1] + c[1,1,-1] + c[1,1,1] + 2.*(c[-1,1,0] + c[1,1,0] + c[0,1,-1] + c[0,1,1]) + 4.*c[0,1,0]; m[3][1] = m1 - m2; m1 = c[-1,-1,-1] + c[-1,1,-1] + c[1,-1,-1] + c[1,1,-1] + 2.*(c[-1,0,-1] + c[1,0,-1] + c[0,-1,-1] + c[0,1,-1]) + 4.*c[0,0,-1]; m2 = c[-1,-1,1] + c[-1,1,1] + c[1,-1,1] + c[1,1,1] + 2.*(c[-1,0,1] + c[1,0,1] + c[0,-1,1] + c[0,1,1]) + 4.*c[0,0,1]; m[3][2] = m1 - m2; /* normalize the set (mx,my,mz): |mx|+|my|+|mz| = 1 */ t0 = fabs(m[3][0]) + fabs(m[3][1]) + fabs(m[3][2]); if (t0 < 1e-30) { coord mxyz = {1., 0., 0.}; return mxyz; } m[3][0] /= t0; m[3][1] /= t0; m[3][2] /= t0; /* choose between the previous choice and Youngs-CIAM */ t0 = fabs (m[3][0]); t1 = fabs (m[3][1]); t2 = fabs (m[3][2]); if (t1 > t0) t0 = t1; if (t2 > t0) t0 = t2; if (fabs(m[cn][cn]) > t0) cn = 3; /* components of the normal vector */ coord mxyz = {m[cn][0], m[cn][1], m[cn][2]}; return mxyz; }``````