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Diffstat (limited to 'math/deboor/colpnt_io.f')
| -rw-r--r-- | math/deboor/colpnt_io.f | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/math/deboor/colpnt_io.f b/math/deboor/colpnt_io.f new file mode 100644 index 00000000..715541eb --- /dev/null +++ b/math/deboor/colpnt_io.f @@ -0,0 +1,65 @@ + subroutine colpnt(k,rho) +c from * a practical guide to splines * by c. de boor +c the k collocation points for the standard interval (-1,1) are sup- +c plied here as the zeros of the legendre polynomial of degree k , +c provided k .le. 8 . otherwise, uniformly spaced points are given. + integer k, j + real rho(k), fkm1o2 + if (k .gt. 8) go to 99 + go to (10,20,30,40,50,60,70,80),k + 10 rho(1) = 0. + return +c$ (single/double) dpdata + 20 rho(2) = .57735 02691 89626 d0 + rho(1) = - rho(2) + return + 30 rho(3) = .77459 66692 41483 d0 + rho(1) = - rho(3) + rho(2) = 0. + return + 40 rho(3) = .33998 10435 84856 d0 + rho(2) = - rho(3) + rho(4) = .86113 63115 94053 d0 + rho(1) = - rho(4) + return + 50 rho(4) = .53846 93101 05683 d0 + rho(2) = - rho(4) + rho(5) = .90617 98459 38664 d0 + rho(1) = - rho(5) + rho(3) = 0. + return + 60 rho(4) = .23861 91860 83197 d0 + rho(3) = - rho(4) + rho(5) = .66120 93864 66265 d0 + rho(2) = - rho(5) + rho(6) = .93246 95142 03152 d0 + rho(1) = - rho(6) + return + 70 rho(5) = .40584 51513 77397 d0 + rho(3) = - rho(5) + rho(6) = .74153 11855 99394 d0 + rho(2) = - rho(6) + rho(7) = .94910 79123 42759 d0 + rho(1) = - rho(7) + rho(4) = 0. + return + 80 rho(5) = .18343 46424 95650 d0 + rho(4) = - rho(5) + rho(6) = .52553 24099 16329 d0 + rho(3) = - rho(6) + rho(7) = .79666 64774 13627 d0 + rho(2) = - rho(7) + rho(8) = .96028 98564 97536 d0 + rho(1) = - rho(8) +c$lbl dpdata + return +c if k .gt. 8, use equispaced points, but print warning + 99 print 699,k + 699 format(11h **********/ + * 49h equispaced collocation points are used since k =,i2, + * 19h is greater than 8.) + fkm1o2 = float(k-1)/2. + do 100 j=1,k + 100 rho(j) = float(j-1)/fkm1o2 - 1. + return + end |