| 13 |
|
|
| 14 |
|
static double m4tmp[4][4]; /* for efficiency */ |
| 15 |
|
|
| 16 |
+ |
#ifdef BSD |
| 17 |
|
#define copymat4(m4a,m4b) bcopy((char *)m4b,(char *)m4a,sizeof(m4tmp)) |
| 18 |
+ |
#else |
| 19 |
+ |
#define copymat4(m4a,m4b) (void)memcpy((char *)m4a,(char *)m4b,sizeof(m4tmp)) |
| 20 |
+ |
extern char *memcpy(); |
| 21 |
+ |
#endif |
| 22 |
|
|
| 23 |
|
|
| 24 |
|
setident4(m4) |
| 56 |
|
register double v3b[3]; |
| 57 |
|
register double m4[4][4]; |
| 58 |
|
{ |
| 59 |
< |
register int i; |
| 59 |
> |
m4tmp[0][0] = v3b[0]*m4[0][0] + v3b[1]*m4[1][0] + v3b[2]*m4[2][0]; |
| 60 |
> |
m4tmp[0][1] = v3b[0]*m4[0][1] + v3b[1]*m4[1][1] + v3b[2]*m4[2][1]; |
| 61 |
> |
m4tmp[0][2] = v3b[0]*m4[0][2] + v3b[1]*m4[1][2] + v3b[2]*m4[2][2]; |
| 62 |
|
|
| 56 |
– |
for (i = 0; i < 3; i++) |
| 57 |
– |
m4tmp[0][i] = v3b[0]*m4[0][i] + |
| 58 |
– |
v3b[1]*m4[1][i] + |
| 59 |
– |
v3b[2]*m4[2][i]; |
| 60 |
– |
|
| 63 |
|
v3a[0] = m4tmp[0][0]; |
| 64 |
|
v3a[1] = m4tmp[0][1]; |
| 65 |
|
v3a[2] = m4tmp[0][2]; |
| 81 |
|
#ifdef INVMAT |
| 82 |
|
/* |
| 83 |
|
* invmat - computes the inverse of mat into inverse. Returns 1 |
| 84 |
< |
* if there exists an inverse, 0 otherwise. It uses Gause Elimination |
| 85 |
< |
* method. |
| 84 |
> |
* if there exists an inverse, 0 otherwise. It uses Gaussian Elimination |
| 85 |
> |
* method with partial pivoting. |
| 86 |
|
*/ |
| 87 |
|
|
| 88 |
|
invmat(inverse,mat) |
| 89 |
|
double mat[4][4],inverse[4][4]; |
| 90 |
|
{ |
| 91 |
|
#define SWAP(a,b,t) (t=a,a=b,b=t) |
| 92 |
+ |
#define ABS(x) (x>=0?x:-(x)) |
| 93 |
|
|
| 94 |
|
register int i,j,k; |
| 95 |
|
register double temp; |
| 96 |
|
|
| 94 |
– |
setident4(inverse); |
| 97 |
|
copymat4(m4tmp, mat); |
| 98 |
+ |
setident(inverse); |
| 99 |
|
|
| 100 |
|
for(i = 0; i < 4; i++) { |
| 101 |
< |
if(m4tmp[i][i] == 0) { /* Pivot is zero */ |
| 102 |
< |
/* Look for a raw with pivot != 0 and swap raws */ |
| 103 |
< |
for(j = i + 1; j < 4; j++) |
| 104 |
< |
if(m4tmp[j][i] != 0) { |
| 105 |
< |
for( k = 0; k < 4; k++) { |
| 106 |
< |
SWAP(m4tmp[i][k],m4tmp[j][k],temp); |
| 107 |
< |
SWAP(inverse[i][k],inverse[j][k],temp); |
| 108 |
< |
} |
| 109 |
< |
break; |
| 110 |
< |
} |
| 111 |
< |
if(j == 4) /* No replacing raw -> no inverse */ |
| 112 |
< |
return(0); |
| 113 |
< |
} |
| 101 |
> |
/* Look for row with largest pivot and swap rows */ |
| 102 |
> |
temp = 0; j = -1; |
| 103 |
> |
for(k = i; k < 4; k++) |
| 104 |
> |
if(ABS(m4tmp[k][i]) > temp) { |
| 105 |
> |
temp = ABS(m4tmp[k][i]); |
| 106 |
> |
j = k; |
| 107 |
> |
} |
| 108 |
> |
if(j == -1) /* No replacing row -> no inverse */ |
| 109 |
> |
return(0); |
| 110 |
> |
if (j != i) |
| 111 |
> |
for(k = 0; k < 4; k++) { |
| 112 |
> |
SWAP(m4tmp[i][k],m4tmp[j][k],temp); |
| 113 |
> |
SWAP(inverse[i][k],inverse[j][k],temp); |
| 114 |
> |
} |
| 115 |
|
|
| 116 |
|
temp = m4tmp[i][i]; |
| 117 |
|
for(k = 0; k < 4; k++) { |
| 129 |
|
} |
| 130 |
|
} |
| 131 |
|
return(1); |
| 132 |
+ |
|
| 133 |
+ |
#undef ABS |
| 134 |
+ |
#undef SWAP |
| 135 |
|
} |
| 136 |
|
#endif |
