[n,sx,incx,sy,incy,sparam]=srotm(n,sx,incx,sy,incy,sparam);

function [n,sx,incx,sy,incy,sparam]=srotm(n,sx,incx,sy,incy,sparam);
persistent firstCall i kx ky nsteps sflag sh11 sh12 sh21 sh22 two w z zero ; if isempty(firstCall),firstCall=1;end; 

if isempty(i), i=0; end;
if isempty(kx), kx=0; end;
if isempty(ky), ky=0; end;
if isempty(nsteps), nsteps=0; end;
if isempty(sflag), sflag=0; end;
if isempty(sh11), sh11=0; end;
if isempty(sh12), sh12=0; end;
if isempty(sh21), sh21=0; end;
if isempty(sh22), sh22=0; end;
if isempty(two), two=0; end;
if isempty(w), w=0; end;
if isempty(z), z=0; end;
if isempty(zero), zero=0; end;
%***BEGIN PROLOGUE  SROTM
%***PURPOSE  Apply a modified Givens transformation.
%***LIBRARY   SLATEC (BLAS)
%***CATEGORY  D1A8
%***TYPE      SINGLE PRECISION (SROTM-S, DROTM-D)
%***KEYWORDS  BLAS, LINEAR ALGEBRA, MODIFIED GIVENS ROTATION, 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)
%       SX  single precision vector with N elements
%     INCX  storage spacing between elements of SX
%       SY  single precision vector with N elements
%     INCY  storage spacing between elements of SY
%   SPARAM  5-element vector. SPARAM(1) is SFLAG described below.
%           Locations 2-5 of SPARAM contain elements of the
%           transformation matrix H described below.
%
%     --Output--
%       SX  rotated vector (unchanged if N .LE. 0)
%       SY  rotated vector (unchanged if N .LE. 0)
%
%     Apply the modified Givens transformation, H, to the 2 by N matrix
%     (SX**T)
%     (SY**T) , where **T indicates transpose.  The elements of SX are
%     in SX(LX+I*INCX), I = 0 to N-1, where LX = 1 if INCX .GE. 0, else
%     LX = 1+(1-N)*INCX, and similarly for SY using LY and INCY.
%
%     With SPARAM(1)=SFLAG, H has one of the following forms:
%
%     SFLAG=-1.0E0     SFLAG=0.0E0        SFLAG=1.0E0     SFLAG=-2.0E0
%
%       (SH11  SH12)    (1.0E0  SH12)    (SH11  1.0E0)    (1.0E0  0.0E0)
%     H=(          )    (          )    (          )    (          )
%       (SH21  SH22),   (SH21  1.0E0),   (-1.0E0 SH22),   (0.0E0  1.0E0).
%
%     See SROTMG for a description of data storage in SPARAM.
%
%***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
%   861211  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  SROTM
sx_shape=size(sx);sx=reshape(sx,1,[]);
sy_shape=size(sy);sy=reshape(sy,1,[]);
if firstCall,   zero =[0.0e0];  end;
if firstCall,  two=[2.0e0];  end;
firstCall=0;
%***FIRST EXECUTABLE STATEMENT  SROTM
sflag = sparam(1);
if( n>0 &&(sflag+two~=zero) )
if( incx~=incy || incx<=0 )
kx = 1;
ky = 1;
if( incx<0 )
kx = fix(1 +(1-n).*incx);
end;
if( incy<0 )
ky = fix(1 +(1-n).*incy);
end;
%
if( sflag<0 )
sh11 = sparam(2);
sh12 = sparam(4);
sh21 = sparam(3);
sh22 = sparam(5);
for i = 1 : n;
w = sx(kx);
z = sy(ky);
sx(kx) = w.*sh11 + z.*sh12;
sy(ky) = w.*sh21 + z.*sh22;
kx = fix(kx + incx);
ky = fix(ky + incy);
end; i = fix(n+1);
elseif( sflag==0 ) ;
sh12 = sparam(4);
sh21 = sparam(3);
for i = 1 : n;
w = sx(kx);
z = sy(ky);
sx(kx) = w + z.*sh12;
sy(ky) = w.*sh21 + z;
kx = fix(kx + incx);
ky = fix(ky + incy);
end; i = fix(n+1);
else;
sh11 = sparam(2);
sh22 = sparam(5);
for i = 1 : n;
w = sx(kx);
z = sy(ky);
sx(kx) = w.*sh11 + z;
sy(ky) = -w + sh22.*z;
kx = fix(kx + incx);
ky = fix(ky + incy);
end; i = fix(n+1);
end;
else;
%
nsteps = fix(n.*incx);
if( sflag<0 )
sh11 = sparam(2);
sh12 = sparam(4);
sh21 = sparam(3);
sh22 = sparam(5);
for i = 1 : incx: nsteps ;
w = sx(i);
z = sy(i);
sx(i) = w.*sh11 + z.*sh12;
sy(i) = w.*sh21 + z.*sh22;
end; i = fix(nsteps +1);
elseif( sflag==0 ) ;
sh12 = sparam(4);
sh21 = sparam(3);
for i = 1 : incx: nsteps ;
w = sx(i);
z = sy(i);
sx(i) = w + z.*sh12;
sy(i) = w.*sh21 + z;
end; i = fix(nsteps +1);
else;
sh11 = sparam(2);
sh22 = sparam(5);
for i = 1 : incx: nsteps ;
w = sx(i);
z = sy(i);
sx(i) = w.*sh11 + z;
sy(i) = -w + sh22.*z;
end; i = fix(nsteps +1);
end;
end;
end;
sx_shape=zeros(sx_shape);sx_shape(:)=sx(1:numel(sx_shape));sx=sx_shape;
sy_shape=zeros(sy_shape);sy_shape(:)=sy(1:numel(sy_shape));sy=sy_shape;
end
%DECK SROTMG