function [return1,return2] = spparms(arg1,arg2)

%SPPARMS Set parameters for sparse matrix routines.

%   SPPARMS('key',value) sets one or more of the "tunable" parameters 

%   used in the sparse routines, particularly sparse / and \.

%

%   SPPARMS, by itself, prints a description of the current settings.

%

%   If no input argument is present, values = SPPARMS returns a

%   vector whose components give the current settings.

%   [keys,values] = SPPARMS returns that vector, and also returns

%   a character matrix whose rows are the keywords for the parameters.

%

%   SPPARMS(values), with no output argument, sets all the parameters

%   to the values specified by the argument vector.

%

%   value = SPPARMS('key') returns the current setting of one parameter.

%

%   SPPARMS('default') sets all the parameters to their default settings.

%   SPPARMS('tight') sets the minimum degree ordering parameters to their 

%   "tight" settings, which may lead to orderings with less fill-in, but 

%   which makes the ordering functions themselves use more execution time.

%

%   The parameters with the default and "tight" values are:

%

%                    keyword       default       tight

%

%      values(1)     'spumoni'      0

%      values(2)     'thr_rel'      1.1          1.0

%      values(3)     'thr_abs'      1.0          0.0

%      values(4)     'exact_d'      0            1

%      values(5)     'supernd'      3            1

%      values(6)     'rreduce'      3            1

%      values(7)     'wh_frac'      0.5          0.5

%      values(8)     'autommd'      1            

%      values(9)     'autoamd'      1

%      values(10)    'piv_tol'      0.1

%      values(11)    'bandden'      0.5

%      values(12)    'umfpack'      1

%      values(13)    'sym_tol'      0.001

%      values(14)    'ldl_tol'      0.01

%

%   The meanings of the parameters are

%

%      spumoni:  The Sparse Monitor Flag controls diagnostic output;

%                0 means none, 1 means some, 2 means too much.

%      thr_rel,

%      thr_abs:  Minimum degree threshold is thr_rel*mindegree + thr_abs.

%      exact_d:  Nonzero to use exact degrees in minimum degree,

%                Zero to use approximate degrees.

%      supernd:  If > 0, MMD amalgamates supernodes every supernd stages.

%      rreduce:  If > 0, MMD does row reduction every rreduce stages.

%      wh_frac:  Rows with density > wh_frac are ignored in COLMMD.

%      autommd:  Nonzero to use SYMMMD and COLMMD orderings with \ and /.

%      autoamd:  Nonzero to use AMD or COLAMD ordering with CHOLMOD, UMFPACK,

%                and SuiteSparseQR in \ and /.

%      piv_tol:  Pivot tolerance used by LU-based (UMFPACK) \ and /.

%      bandden:  Backslash uses band solver if band density is > bandden.

%                If bandden = 1.0, never use band solver.

%                If bandden = 0.0, always use band solver.

%      umfpack:  Nonzero to use UMFPACK instead of the v4 LU-based solver

%                in \ and /.

%      sym_tol:  Symmetric pivot tolerance used by UMFPACK.  See LU for

%                more information about the role of the symmetric pivot

%                tolerance.

%      ldl_tol:  Pivot tolerance used by LDL-based (MA57) \ and /.

%

%   Note:

%   Solving symmetric positive definite matrices within \ and /:

%      The CHOLMOD CHOL-based solver uses AMD.

%   Solving general square matrices within \ and /:

%      The UMFPACK LU-based solver uses either AMD or a modified COLAMD.

%      The v4 LU-based solver uses COLMMD.

%   Solving rectangular matrices within \ and /:

%      The SuiteSparseQR QR-based solver uses COLAMD.

%   All of these algorithms respond to SPPARMS('autoamd') except for the

%   v4 LU-based, which responds to SPPARMS('autommd').

%

%   See also AMD, COLAMD, SYMAMD.

%   Copyright 1984-2011 The MathWorks, Inc.

% The following are "constants".

allkeys = ['spumoni' 

           'thr_rel'

           'thr_abs'

           'exact_d'

           'supernd'

           'rreduce'

           'wh_frac'

           'autommd'

           'autoamd'

           'piv_tol'

           'bandden'

           'umfpack'

           'sym_tol'

           'ldl_tol'

           'usema57'

           'spqrtol'

           'chmodsp'];

nparms = size(allkeys,1); 

spuparmrange = 1:1;   % Which parameters pertain to SPUMONI? 

mmdparmrange = 2:7;   % Which parameters pertain to minimum degree? 

bslparmrange = 8:16;  % Which parameters pertain to sparse backslash? 

cspparmrange = 17:17; 

defaultparms = [0 1.1 1.0 0 3 3 0.5 1 1 0.1 0.5 1 0.001 0.01 1 -2 0]'; 

tightmmdparms   = [1.0 0.0 1 1 1 0.5]'; 

% First find out what the current parameters are.

oldvalues = zeros(nparms,1); 

oldvalues(spuparmrange) = sparsfun('spumoni'); 

oldvalues(mmdparmrange) = sparsfun('mmdset'); 

oldvalues(bslparmrange) = sparsfun('slashset'); 

oldvalues(cspparmrange) = sparsfun('chmodsp'); 

% No input args, no output args:  Describe current settings.

if nargin == 0 && nargout == 0 

    a = num2str(oldvalues(1));

    if oldvalues(1) 

      fprintf('%s',getString(message('MATLAB:spparms:SparseMonitorOutputLevel', a)));

    else 

      fprintf('%s',getString(message('MATLAB:spparms:NoSparseMonitorOutput')));

    end

    a = num2str(oldvalues(2));

    b = num2str(oldvalues(3));

    fprintf('%s',getString(message('MATLAB:spparms:MmdThreshold', a, b)));

    if oldvalues(4) 

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:UsingExactDegreesInAprimeA')));

    else 

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:UsingApproximateDegreesInAprimeA')));

    end

    s = int2str(oldvalues(5));

    if oldvalues(5)

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:SupernodeAmalgamationEveryNStages', s)));

    else

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:NoSupernodeAmalgamation')));

    end

    s = int2str(oldvalues(6));

    if oldvalues(6) 

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:RowReductionEveryNStages', s)));

    else

        fprintf('     ');

        fprintf(getString(message('MATLAB:spparms:NoRowReductionn')));

    end

    a = num2str(100*oldvalues(7));

    if oldvalues(7)

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:WithholdRowsAtLeastNPercentDenseInColmmd', a)));

    else

        fprintf('     ');

        fprintf('%s',getString(message('MATLAB:spparms:NoRowWithholdingInColmmd')));

    end

    if oldvalues(8)

      fprintf('%s',getString(message('MATLAB:spparms:MinimumDegreeOrderingsUsedWithV4')));

    else

      fprintf('%s',getString(message('MATLAB:spparms:NoAutomaticOrderingsUsedWithV4')));

    end

    if oldvalues(9)

      fprintf('%s',getString(message('MATLAB:spparms:ApproximateMinimumDegreeOrderingsUsedCholmodUmfpack')));

    else

      fprintf('%s',getString(message('MATLAB:spparms:NoAutomaticOrderingsUsedWithCholmodUmfpack')));

    end

    a = num2str(oldvalues(10));

    fprintf('%s',getString(message('MATLAB:spparms:PivotToleranceOfUsedByUMFPACK', a)));

    a = num2str(oldvalues(11));

    fprintf('%s',getString(message('MATLAB:spparms:BackslashUsesBandSolverIfBandDensityGT', a)));

    if oldvalues(12)

        fprintf('%s',getString(message('MATLAB:spparms:UMFPACKUsedForLu')));

    else

        fprintf('%s',getString(message('MATLAB:spparms:V4AlgorithmUsedForLu')));

    end

    a = num2str(oldvalues(13));

    fprintf('%s',getString(message('MATLAB:spparms:SymmetricPivotToleranceUsedByUMFPACK', a)));

    a = num2str(oldvalues(14));

    fprintf('%s',getString(message('MATLAB:spparms:PivotToleranceUsedByMA57', a)));

    return;

% No input args, one or two output args:  Return current settings.

elseif nargin == 0 && nargout > 0 

    if nargout <= 1

        return1 = oldvalues;

    else

        return1 = allkeys;

        return2 = oldvalues;

    end

    return;

% One input arg of suitable size:  Reset all parameters.

elseif nargin == 1 && length(arg1) == nparms && min(size(arg1)) == 1 

    if nargout > 0 

        error (message('MATLAB:spparms:TooManyOutputs'))

    end

    sparsfun('spumoni',arg1(spuparmrange));

    sparsfun('mmdset',arg1(mmdparmrange));

    sparsfun('slashset',arg1(bslparmrange));

    sparsfun('chmodsp',arg1(cspparmrange));

    return;

% Input arg 'tight':  Reset minimum degree parameters.

elseif nargin == 1 && strcmpi(arg1,'tight') 

    if nargout > 0

        error (message('MATLAB:spparms:TooManyOutputs'))

    end

    newvalues = oldvalues;

    newvalues(mmdparmrange) = tightmmdparms;

    spparms(newvalues);

    return;

% Input arg 'default':  Reset all parameters.

elseif nargin == 1 && strcmpi(arg1,'default') 

    if nargout > 0

        error (message('MATLAB:spparms:TooManyOutputs'))

    end

    spparms(defaultparms);

    return;

% One input arg:  Return one current setting.

elseif (nargin == 1) 

    if ~ischar(arg1) 

        error (message('MATLAB:spparms:OptionNotString'))

    end

    if nargout > 1 

        error (message('MATLAB:spparms:TooManyOutputs'))

    end

    if size(arg1,1) > 1 

        error (message('MATLAB:spparms:TooManyParamsPerKeyword'))

    end

    key = lower(arg1); 

    for i = 1:nparms 

        if strcmp (key, allkeys(i,:)) 

            return1 = oldvalues(i); 

            return; 

        end

    end

    error(message('MATLAB:spparms:UnknownKeyword', key));

% Two input args:  Reset some parameters.

else

    if ~ischar(arg1)

        error (message('MATLAB:spparms:OptionNotString'));

    end

    if nargout > 0

        error (message('MATLAB:spparms:TooManyOutputs'));

    end

    if size(arg1,1) ~= length(arg2)

        error (message('MATLAB:spparms:ParamsMismatchKeywords'));

    end

    newvalues = oldvalues;

    for k = 1:size(arg1,1)

        key = lower(arg1(k,:));

        value = arg2(k);

        found = 0;

        for i = 1:nparms

            if strcmp (key, allkeys(i,:))

                newvalues(i) = value;

                found = 1;

                break

            end

        end

        if ~found

            warning(message('MATLAB:spparms:UnknownKeyword', key));

        end

    end

    spparms(newvalues);

    return;

end