| [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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