[initdsresult,os,nos,eta]=initds(os,nos,eta);

function [initdsresult,os,nos,eta]=initds(os,nos,eta);
initdsresult=[];
persistent err i ii initds ; 

if isempty(err), err=0; end;
if isempty(i), i=0; end;
if isempty(ii), ii=0; end;
if isempty(initdsresult), initdsresult=0; end;
%***BEGIN PROLOGUE  INITDS
%***PURPOSE  Determine the number of terms needed in an orthogonal
%            polynomial series so that it meets a specified accuracy.
%***LIBRARY   SLATEC (FNLIB)
%***CATEGORY  C3A2
%***TYPE      doubleprecision (INITS-S, INITDS-D)
%***KEYWORDS  CHEBYSHEV, FNLIB, INITIALIZE, ORTHOGONAL POLYNOMIAL,
%             ORTHOGONAL SERIES, SPECIAL FUNCTIONS
%***AUTHOR  Fullerton, W., (LANL)
%***DESCRIPTION
%
%  Initialize the orthogonal series, represented by the array OS, so
%  that INITDS is the number of terms needed to insure the error is no
%  larger than ETA.  Ordinarily, ETA will be chosen to be one-tenth
%  machine precision.
%
%             Input Arguments --
%   OS     doubleprecision array of NOS coefficients in an orthogonal
%          series.
%   NOS    number of coefficients in OS.
%   ETA    single precision scalar containing requested accuracy of
%          series.
%
%***REFERENCES  (NONE)
%***ROUTINES CALLED  XERMSG
%***REVISION HISTORY  (YYMMDD)
%   770601  DATE WRITTEN
%   890531  Changed all specific intrinsics to generic.  (WRB)
%   890831  Modified array declarations.  (WRB)
%   891115  Modified error message.  (WRB)
%   891115  REVISION DATE from Version 3.2
%   891214  Prologue converted to Version 4.0 format.  (BAB)
%   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
%***end PROLOGUE  INITDS
os_shape=size(os);os=reshape(os,1,[]);
%***FIRST EXECUTABLE STATEMENT  INITDS
if( nos<1 )
xermsg('SLATEC','INITDS','Number of coefficients is less than 1',2,1);
end;
%
err = 0.;
for ii = 1 : nos;
i = fix(nos + 1 - ii);
err = err + abs(real(os(i)));
if( err>eta )
break;
end;
end;
%
if( i==nos )
xermsg('SLATEC','INITDS','Chebyshev series too short for specified accuracy',1,1);
end;
initdsresult = fix(i);
%
os_shape=zeros(os_shape);os_shape(:)=os(1:numel(os_shape));os=os_shape;
csnil=dbstack(1); csnil=csnil(1).name(1)~='@';
if csnil&&~isempty(inputname(1)), assignin('caller','FUntemp',os); evalin('caller',[inputname(1),'=FUntemp;']); end
if csnil&&~isempty(inputname(2)), assignin('caller','FUntemp',nos); evalin('caller',[inputname(2),'=FUntemp;']); end
if csnil&&~isempty(inputname(3)), assignin('caller','FUntemp',eta); evalin('caller',[inputname(3),'=FUntemp;']); end
end
%DECK INITS