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double precision function bnorm (n, a, nra, ml, mu, w)
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c-----------------------------------------------------------------------
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c this function computes the norm of a banded n by n matrix,
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c stored in the array a, that is consistent with the weighted max-norm
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c on vectors, with weights stored in the array w.
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c ml and mu are the lower and upper half-bandwidths of the matrix.
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c nra is the first dimension of the a array, nra .ge. ml+mu+1.
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c in terms of the matrix elements a(i,j), the norm is given by..
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c bnorm = max(i=1,...,n) ( w(i) * sum(j=1,...,n) abs(a(i,j))/w(j) )
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c-----------------------------------------------------------------------
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integer n, nra, ml, mu
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integer i, i1, jlo, jhi, j
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double precision an, sum
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dimension a(nra,n), w(n)
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10 sum = sum + dabs(a(i1-j,j))/w(j)
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an = dmax1(an,sum*w(i))
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c----------------------- end of function bnorm -------------------------