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c Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
c Copyright (C) ????-2008 - INRIA
c
c This file must be used under the terms of the CeCILL.
c This source file is licensed as described in the file COPYING, which
c you should have received as part of this distribution. The terms
c are also available at
c http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt
subroutine nextk(type)
c computes the next k polynomials using scalars
c computed in calcsc
common /gloglo/ p, qp, k, qk, svk, sr, si, u,
* v, a, b, c, d, a1, a2, a3, a6, a7, e, f, g,
* h, szr, szi, lzr, lzi, eta, are, mre, n, nn
double precision p(101), qp(101), k(101),
* qk(101), svk(101), sr, si, u, v, a, b, c, d,
* a1, a2, a3, a6, a7, e, f, g, h, szr, szi,
* lzr, lzi
real eta, are, mre
integer n, nn
double precision temp
integer type
if (type.eq.3) go to 40
temp = a
if (type.eq.1) temp = b
if (abs(a1).gt.abs(temp)*eta*10.) go to 20
c if a1 is nearly zero then use a special form of the
c recurrence
k(1) = 0.0d+0
k(2) = -a7*qp(1)
do 10 i=3,n
k(i) = a3*qk(i-2) - a7*qp(i-1)
10 continue
return
c use scaled form of the recurrence
20 a7 = a7/a1
a3 = a3/a1
k(1) = qp(1)
k(2) = qp(2) -a7*qp(1)
do 30 i=3,n
k(i) = a3*qk(i-2) - a7*qp(i-1) + qp(i)
30 continue
return
c use unscaled form of the recurrence if type is 3
40 k(1) = 0.0d+0
k(2) = 0.0d+0
do 50 i=3,n
k(i) = qk(i-2)
50 continue
return
end
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