[dnrm2result,n,dx,incx]=dnrm2(n,dx,incx);

function [dnrm2result,n,dx,incx]=dnrm2(n,dx,incx);
dnrm2result=[];
persistent cuthi cutlo firstCall hitest i j next nn one summlv xmax zero ; if isempty(firstCall),firstCall=1;end; 

;
if isempty(i), i=0; end;
if isempty(j), j=0; end;
if isempty(nn), nn=0; end;
%***BEGIN PROLOGUE  DNRM2
%***PURPOSE  Compute the Euclidean length (L2 norm) of a vector.
%***LIBRARY   SLATEC (BLAS)
%***CATEGORY  D1A3B
%***TYPE      doubleprecision (SNRM2-S, DNRM2-D, SCNRM2-C)
%***KEYWORDS  BLAS, EUCLIDEAN LENGTH, EUCLIDEAN NORM, L2,
%             LINEAR ALGEBRA, UNITARY, VECTOR
%***AUTHOR  Lawson, C. L., (JPL)
%           Hanson, R. J., (SNLA)
%           Kincaid, D. R., (U. of Texas)
%           Krogh, F. T., (JPL)
%***DESCRIPTION
%
%                B L A S  Subprogram
%    Description of parameters
%
%     --Input--
%        N  number of elements in input vector(s)
%       DX  doubleprecision vector with N elements
%     INCX  storage spacing between elements of DX
%
%     --Output--
%    DNRM2  doubleprecision result (zero if N .LE. 0)
%
%     Euclidean norm of the N-vector stored in DX with storage
%     increment INCX.
%     If N .LE. 0, return with result = 0.
%     If N .GE. 1, then INCX must be .GE. 1
%
%     Four phase method using two built-in constants that are
%     hopefully applicable to all machines.
%         CUTLO = maximum of  SQRT(U/EPS)  over all known machines.
%         CUTHI = minimum of  SQRT(V)      over all known machines.
%     where
%         EPS = smallest no. such that EPS + 1. .GT. 1.
%         U   = smallest positive no.   (underflow limit)
%         V   = largest  no.            (overflow  limit)
%
%     Brief outline of algorithm.
%
%     Phase 1 scans zero components.
%     move to phase 2 when a component is nonzero and .LE. CUTLO
%     move to phase 3 when a component is .GT. CUTLO
%     move to phase 4 when a component is .GE. CUTHI/M
%     where M = N for X() real and M = 2*N for complex.
%
%     Values for CUTLO and CUTHI.
%     From the environmental parameters listed in the IMSL converter
%     document the limiting values are as follows:
%     CUTLO, S.P.   U/EPS = 2**(-102) for  Honeywell.  Close seconds are
%                   Univac and DEC at 2**(-103)
%                   Thus CUTLO = 2**(-51) = 4.44089E-16
%     CUTHI, S.P.   V = 2**127 for Univac, Honeywell, and DEC.
%                   Thus CUTHI = 2**(63.5) = 1.30438E19
%     CUTLO, D.P.   U/EPS = 2**(-67) for Honeywell and DEC.
%                   Thus CUTLO = 2**(-33.5) = 8.23181D-11
%     CUTHI, D.P.   same as S.P.  CUTHI = 1.30438D19
%     DATA CUTLO, CUTHI /8.232D-11,  1.304D19/
%     DATA CUTLO, CUTHI /4.441E-16,  1.304E19/
%
%***REFERENCES  C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.
%                 Krogh, Basic linear algebra subprograms for Fortran
%                 usage, Algorithm No. 539, Transactions on Mathematical
%                 Software 5, 3 (September 1979), pp. 308-323.
%***ROUTINES CALLED  (NONE)
%***REVISION HISTORY  (YYMMDD)
%   791001  DATE WRITTEN
%   890531  Changed all specific intrinsics to generic.  (WRB)
%   890831  Modified array declarations.  (WRB)
%   890831  REVISION DATE from Version 3.2
%   891214  Prologue converted to Version 4.0 format.  (BAB)
%   920501  Reformatted the REFERENCES section.  (WRB)
%***end PROLOGUE  DNRM2
if isempty(next), next=0; end;
dx_shape=size(dx);dx=reshape(dx,1,[]);
if isempty(cutlo), cutlo=0; end;
if isempty(cuthi), cuthi=0; end;
if isempty(hitest), hitest=0; end;
if isempty(summlv), summlv=0; end;
if isempty(xmax), xmax=0; end;
if isempty(zero), zero=0; end;
if isempty(one), one=0; end;
if firstCall,   zero =[0.0d0];  end;
if firstCall,  one=[1.0d0];  end;
%
if firstCall,   cutlo =[8.232d-11];  end;
if firstCall,  cuthi=[1.304d19];  end;
firstCall=0;
%***FIRST EXECUTABLE STATEMENT  DNRM2

[dnrm2result,n,dx,incx]=snrm2(n,dx,incx);
end