// SPDVERIF Symmetric Positive Definite Stiffness Matrix Verificator
//
// =========================================================================
// SYNTAX: SPDverif(K0,cDOFasc,K)
// =========================================================================
//
// SPDVERIF Subroutine part of MABS3D
// (c)2010, Marcos C. Ruggeri
// mruggeri@frh.utn.edu.ar
// Universidad Tecnologica Nacional
// Facultad Regional Haedo
// Departamento Aeronautica
//
//   Copyright 2010 Marcos C. Ruggeri
//   $Revision: //REV 1.7 2010/08/08

//REV 1.6 2010/06/31------------START SPD VERIFICATION----------------------
function SPDverif(K0,cDOFasc,K)
  lines0_K0=zeroslines(K0);
  for i=1:length(lines0_K0)
    flag=0;
    for h=1:length(cDOFasc)
      if lines0_K0(i)==cDOFasc(h)
        flag=1;
        break
      else
      end
    end
    if flag==0 //Unconstrained DOF lin0_K0 not was removed by cDOF
      //Detecting possibility of corresponding unconstrained node to
      //uncDOF.
      uncDOF=lines0_K0(i);
      npos1=(uncDOF+2)/3; //x-direction
      npos2=(uncDOF+1)/3; //y-direction
      npos3=uncDOF/3; //z-direction
      if npos1==fix(npos1)
        uncn=npos1;
        comp=1; //DOF-component
      elseif npos2==fix(npos2)
        uncn=npos2;
        comp=2;
      else
        uncn=npos3;
        comp=3;
      end      
      warning(['RIGID BODY MOTION IN DOF-COMPONENT ',string(comp),' (DOF:',string(uncDOF),') FROM NODE ',string(uncn),' IS NOT PREVENTED.'])
    else
    end
  end
  if det(K)==0
    error('ACTIVE STIFFNESS MATRIX OF STRUCTURE IS SINGULAR. CHECK BOUNDARY CONDITIONS.')
  end
endfunction
//REV 1.6 2010/06/31------------END SPD VERIFICATION------------------------
function lines0_K0=zeroslines(K0)
  lines0=[];
  cont=0;
  for j=1:length(K0)
    if K0(:,j)==0
      cont=cont+1;
      lines0(cont)=j;
    else
    end
  end
endfunction
//Translated by LBD 2010/11/09