Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
git-svn-id: https://openmodelica.org/svn/OpenModelica/trunk@1695 f25d12d1-65f4-0310-ae8a-bbce733d8d8e
- Loading branch information
Peter Aronsson
committed
Apr 20, 2005
1 parent
4357815
commit 6d9159c
Showing
1 changed file
with
95 additions
and
0 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,95 @@ | ||
subroutine qform(m,n,q,ldq,wa) | ||
integer m,n,ldq | ||
double precision q(ldq,m),wa(m) | ||
c ********** | ||
c | ||
c subroutine qform | ||
c | ||
c this subroutine proceeds from the computed qr factorization of | ||
c an m by n matrix a to accumulate the m by m orthogonal matrix | ||
c q from its factored form. | ||
c | ||
c the subroutine statement is | ||
c | ||
c subroutine qform(m,n,q,ldq,wa) | ||
c | ||
c where | ||
c | ||
c m is a positive integer input variable set to the number | ||
c of rows of a and the order of q. | ||
c | ||
c n is a positive integer input variable set to the number | ||
c of columns of a. | ||
c | ||
c q is an m by m array. on input the full lower trapezoid in | ||
c the first min(m,n) columns of q contains the factored form. | ||
c on output q has been accumulated into a square matrix. | ||
c | ||
c ldq is a positive integer input variable not less than m | ||
c which specifies the leading dimension of the array q. | ||
c | ||
c wa is a work array of length m. | ||
c | ||
c subprograms called | ||
c | ||
c fortran-supplied ... min0 | ||
c | ||
c argonne national laboratory. minpack project. march 1980. | ||
c burton s. garbow, kenneth e. hillstrom, jorge j. more | ||
c | ||
c ********** | ||
integer i,j,jm1,k,l,minmn,np1 | ||
double precision one,sum,temp,zero | ||
data one,zero /1.0d0,0.0d0/ | ||
c | ||
c zero out upper triangle of q in the first min(m,n) columns. | ||
c | ||
minmn = min0(m,n) | ||
if (minmn .lt. 2) go to 30 | ||
do 20 j = 2, minmn | ||
jm1 = j - 1 | ||
do 10 i = 1, jm1 | ||
q(i,j) = zero | ||
10 continue | ||
20 continue | ||
30 continue | ||
c | ||
c initialize remaining columns to those of the identity matrix. | ||
c | ||
np1 = n + 1 | ||
if (m .lt. np1) go to 60 | ||
do 50 j = np1, m | ||
do 40 i = 1, m | ||
q(i,j) = zero | ||
40 continue | ||
q(j,j) = one | ||
50 continue | ||
60 continue | ||
c | ||
c accumulate q from its factored form. | ||
c | ||
do 120 l = 1, minmn | ||
k = minmn - l + 1 | ||
do 70 i = k, m | ||
wa(i) = q(i,k) | ||
q(i,k) = zero | ||
70 continue | ||
q(k,k) = one | ||
if (wa(k) .eq. zero) go to 110 | ||
do 100 j = k, m | ||
sum = zero | ||
do 80 i = k, m | ||
sum = sum + q(i,j)*wa(i) | ||
80 continue | ||
temp = sum/wa(k) | ||
do 90 i = k, m | ||
q(i,j) = q(i,j) - temp*wa(i) | ||
90 continue | ||
100 continue | ||
110 continue | ||
120 continue | ||
return | ||
c | ||
c last card of subroutine qform. | ||
c | ||
end |