1 2 #ifndef lint 3 static char vcid[] = "$Id: baijfact.c,v 1.6 1996/02/20 18:52:30 curfman Exp bsmith $"; 4 #endif 5 6 /* 7 This file creating by running f2c 8 linpack. this version dated 08/14/78 9 cleve moler, university of new mexico, argonne national lab. 10 11 Computes the inverse of a matrix given its factors and pivots 12 calculated by Linpack_DGEFA(). 13 */ 14 15 #include "petsc.h" 16 17 int Linpack_DGEDI(Scalar *a,int n,int *ipvt,Scalar *work) 18 { 19 int a_offset, i__2,kb, kp1, nm1,i, j, k, l, ll; 20 Scalar t, *aa,*ax,*ay,tmp; 21 22 --work; 23 --ipvt; 24 a_offset = n + 1; 25 a -= a_offset; 26 27 /* compute inverse(u) */ 28 29 for (k = 1; k <= n; ++k) { 30 a[k + k * n] = 1. / a[k + k * n]; 31 t = -a[k + k * n]; 32 i__2 = k - 1; 33 /* dscal_(&i__2, &t, &a[k * n + 1], &c__1); */ 34 aa = &a[k * n + 1]; 35 for ( ll=0; ll<i__2; ll++ ) aa[ll] *= t; 36 kp1 = k + 1; 37 if (n < kp1) continue; 38 ax = aa; 39 for (j = kp1; j <= n; ++j) { 40 t = a[k + j * n]; 41 a[k + j * n] = 0.; 42 /* daxpy_(&k, &t, &a[k * n + 1], &c__1, &a[j * n + 1], &c__1);*/ 43 ay = &a[j * n + 1]; 44 for ( ll=0; ll<k; ll++ ) { 45 ay[ll] += t*ax[ll]; 46 } 47 } 48 } 49 50 /* form inverse(u)*inverse(l) */ 51 52 nm1 = n - 1; 53 if (nm1 < 1) { 54 return 0; 55 } 56 for (kb = 1; kb <= nm1; ++kb) { 57 k = n - kb; 58 kp1 = k + 1; 59 aa = a + k * n; 60 for (i = kp1; i <= n; ++i) { 61 work[i] = aa[i]; 62 aa[i] = 0.; 63 } 64 for (j = kp1; j <= n; ++j) { 65 t = work[j]; 66 /* daxpy_(n, &t, &a[j * n + 1], &c__1, &a[k * n + 1], &c__1);*/ 67 ax = &a[j * n + 1]; 68 ay = &a[k * n + 1]; 69 for ( ll=0; ll<n; ll++ ) { 70 ay[ll] += t*ax[ll]; 71 } 72 } 73 l = ipvt[k]; 74 if (l != k) { 75 /* dswap_(n, &a[k * n + 1], &c__1, &a[l * n + 1], &c__1); */ 76 ax = &a[k * n + 1]; 77 ay = &a[l * n + 1]; 78 for ( ll=0; ll<n; ll++ ) { 79 tmp = ax[ll]; 80 ax[ll] = ay[ll]; 81 ay[ll] = tmp; 82 } 83 } 84 } 85 return 0; 86 } 87 88