Code covered by the BSD License  

Highlights from
slatec

from slatec by Ben Barrowes
The slatec library converted into matlab functions.

[n,da,dx,incx,dy,incy]=daxpy(n,da,dx,incx,dy,incy);
function [n,da,dx,incx,dy,incy]=daxpy(n,da,dx,incx,dy,incy);
persistent i ix iy m mp1 ns ; 

if isempty(i), i=0; end;
if isempty(ix), ix=0; end;
if isempty(iy), iy=0; end;
if isempty(m), m=0; end;
if isempty(mp1), mp1=0; end;
if isempty(ns), ns=0; end;
%***BEGIN PROLOGUE  DAXPY
%***PURPOSE  Compute a constant times a vector plus a vector.
%***LIBRARY   SLATEC (BLAS)
%***CATEGORY  D1A7
%***TYPE      doubleprecision (SAXPY-S, DAXPY-D, CAXPY-C)
%***KEYWORDS  BLAS, LINEAR ALGEBRA, TRIAD, 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)
%       DA  doubleprecision scalar multiplier
%       DX  doubleprecision vector with N elements
%     INCX  storage spacing between elements of DX
%       DY  doubleprecision vector with N elements
%     INCY  storage spacing between elements of DY
%
%     --Output--
%       DY  doubleprecision result (unchanged if N .LE. 0)
%
%     Overwrite doubleprecision DY with doubleprecision DA*DX + DY.
%     For I = 0 to N-1, replace  DY(LY+I*INCY) with DA*DX(LX+I*INCX) +
%       DY(LY+I*INCY),
%     where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is
%     defined in a similar way using INCY.
%
%***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
%   890831  Modified array declarations.  (WRB)
%   890831  REVISION DATE from Version 3.2
%   891214  Prologue converted to Version 4.0 format.  (BAB)
%   920310  Corrected definition of LX in DESCRIPTION.  (WRB)
%   920501  Reformatted the REFERENCES section.  (WRB)
%***end PROLOGUE  DAXPY
dx_shape=size(dx);dx=reshape(dx,1,[]);
dy_shape=size(dy);dy=reshape(dy,1,[]);
%***FIRST EXECUTABLE STATEMENT  DAXPY
if( n<=0 || da==0.0d0 )
dx_shape=zeros(dx_shape);dx_shape(:)=dx(1:numel(dx_shape));dx=dx_shape;
dy_shape=zeros(dy_shape);dy_shape(:)=dy(1:numel(dy_shape));dy=dy_shape;
return;
end;
if( incx==incy )
if( incx<1 )
elseif( incx==1 ) ;
%
%     Code for both increments equal to 1.
%
%     Clean-up loop so remaining vector length is a multiple of 4.
%
m = fix(rem(n,4));
if( m~=0 )
for i = 1 : m;
dy(i) = dy(i) + da.*dx(i);
end; i = fix(m+1);
if( n<4 )
dx_shape=zeros(dx_shape);dx_shape(:)=dx(1:numel(dx_shape));dx=dx_shape;
dy_shape=zeros(dy_shape);dy_shape(:)=dy(1:numel(dy_shape));dy=dy_shape;
return;
end;
end;
mp1 = fix(m + 1);
for i = mp1 : 4: n ;
dy(i) = dy(i) + da.*dx(i);
dy(i+1) = dy(i+1) + da.*dx(i+1);
dy(i+2) = dy(i+2) + da.*dx(i+2);
dy(i+3) = dy(i+3) + da.*dx(i+3);
end; i = fix(n +1);
dx_shape=zeros(dx_shape);dx_shape(:)=dx(1:numel(dx_shape));dx=dx_shape;
dy_shape=zeros(dy_shape);dy_shape(:)=dy(1:numel(dy_shape));dy=dy_shape;
return;
else;
%
%     Code for equal, positive, non-unit increments.
%
ns = fix(n.*incx);
for i = 1 : incx: ns ;
dy(i) = da.*dx(i) + dy(i);
end; i = fix(ns +1);
dx_shape=zeros(dx_shape);dx_shape(:)=dx(1:numel(dx_shape));dx=dx_shape;
dy_shape=zeros(dy_shape);dy_shape(:)=dy(1:numel(dy_shape));dy=dy_shape;
return;
end;
end;
%
%     Code for unequal or nonpositive increments.
%
ix = 1;
iy = 1;
if( incx<0 )
ix =fix((-n+1).*incx + 1);
end;
if( incy<0 )
iy =fix((-n+1).*incy + 1);
end;
for i = 1 : n;
dy(iy) = dy(iy) + da.*dx(ix);
ix = fix(ix + incx);
iy = fix(iy + incy);
end; i = fix(n+1);
dx_shape=zeros(dx_shape);dx_shape(:)=dx(1:numel(dx_shape));dx=dx_shape;
dy_shape=zeros(dy_shape);dy_shape(:)=dy(1:numel(dy_shape));dy=dy_shape;
return;
end
%DECK DBCG

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