more QR & Cholesky updating functions

[John W. Eaton]

On  7-Apr-2008, Jaroslav Hajek wrote:

| attached is a changeset implementing the updating functions
| cholinsert, choldelete, qrshift and cholshift on top
| of the corresponding new member functions in the QR, ComplexQR, CHOL
| and ComplexCHOL classes.

I applied it.  I had to make the following change to avoid the
following error:

  g77 -c -fPIC -O /home/jwe/src/octave/libcruft/qrupdate/dchdex.f -o 
pic/dchdex.o
  /home/jwe/src/octave/libcruft/qrupdate/zchinx.f: In subroutine `zchinx':
  /home/jwe/src/octave/libcruft/qrupdate/zchinx.f:45: 
             if (real(u(1)) <= 0) then
                 ^
  Ambiguous use of intrinsic `REAL' at (^) [info -f g77 M CMPAMBIG]
  /home/jwe/src/octave/libcruft/qrupdate/zchinx.f:49: 
               R(1,1) = sqrt(real(u(1)))
                             ^
  Ambiguous use of intrinsic `REAL' at (^) [info -f g77 M CMPAMBIG]


Thanks,

jwe


diff --git a/libcruft/qrupdate/zchinx.f b/libcruft/qrupdate/zchinx.f
--- a/libcruft/qrupdate/zchinx.f
+++ b/libcruft/qrupdate/zchinx.f
@@ -42,11 +42,11 @@ c               definiteness.
 
 c quick return if possible
       if (n == 0) then
-        if (real(u(1)) <= 0) then
+        if (dble(u(1)) <= 0) then
           info = 1
           return
         else
-          R(1,1) = sqrt(real(u(1)))
+          R(1,1) = sqrt(dble(u(1)))
         end if
       end if