evalue.cc
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00001 //$$evalue.cpp                           eigen-value decomposition
00002 
00003 // Copyright (C) 1991,2,3,4: R B Davies
00004 
00005 #define WANT_MATH
00006 
00007 #include "include.h"
00008 #include "newmatap.h"
00009 #include "newmatrm.h"
00010 #include "precisio.h"
00011 
00012 #ifdef use_namespace
00013 namespace NEWMAT {
00014 #endif
00015 
00016 #ifdef DO_REPORT
00017 #define REPORT { static ExeCounter ExeCount(__LINE__,17); ++ExeCount; }
00018 #else
00019 #define REPORT {}
00020 #endif
00021 
00022 
00023 
00024 static void tred2(const SymmetricMatrix& A, DiagonalMatrix& D,
00025    DiagonalMatrix& E, Matrix& Z)
00026 {
00027    Tracer et("Evalue(tred2)");
00028    REPORT
00029    Real tol =
00030       FloatingPointPrecision::Minimum()/FloatingPointPrecision::Epsilon();
00031    int n = A.Nrows(); Z.ReSize(n,n); Z.Inject(A);
00032    D.ReSize(n); E.ReSize(n);
00033    Real* z = Z.Store(); int i;
00034 
00035    for (i=n-1; i > 0; i--)                   // i=0 is excluded
00036    {
00037       Real f = Z.element(i,i-1); Real g = 0.0;
00038       int k = i-1; Real* zik = z + i*n;
00039       while (k--) g += square(*zik++);
00040       Real h = g + square(f);
00041       if (g <= tol) { REPORT E.element(i) = f; h = 0.0; }
00042       else
00043       {
00044          REPORT
00045          g = sign(-sqrt(h), f); E.element(i) = g; h -= f*g;
00046          Z.element(i,i-1) = f-g; f = 0.0;
00047          Real* zji = z + i; Real* zij = z + i*n; Real* ej = E.Store();
00048          int j;
00049          for (j=0; j<i; j++)
00050          {
00051             *zji = (*zij++)/h; g = 0.0;
00052             Real* zjk = z + j*n; zik = z + i*n;
00053             k = j; while (k--) g += *zjk++ * (*zik++);
00054             k = i-j;
00055             if (k) for(;;)
00056                { g += *zjk * (*zik++); if (!(--k)) break; zjk += n; }
00057             *ej++ = g/h; f += g * (*zji); zji += n;
00058          }
00059          Real hh = f / (h + h); zij = z + i*n; ej = E.Store();
00060          for (j=0; j<i; j++)
00061          {
00062             f = *zij++; g = *ej - hh * f; *ej++ = g;
00063             Real* zjk = z + j*n; Real* zik = z + i*n;
00064             Real* ek = E.Store(); k = j+1;
00065             while (k--)  *zjk++ -= ( f*(*ek++) + g*(*zik++) ); 
00066          }
00067       }
00068       D.element(i) = h;
00069    }
00070 
00071    D.element(0) = 0.0; E.element(0) = 0.0;
00072    for (i=0; i<n; i++)
00073    {
00074       if (D.element(i) != 0.0)
00075       {
00076          REPORT
00077          for (int j=0; j<i; j++)
00078          {
00079             Real g = 0.0;
00080             Real* zik = z + i*n; Real* zkj = z + j;
00081             int k = i;
00082             if (k) for (;;)
00083                { g += *zik++ * (*zkj); if (!(--k)) break; zkj += n; }
00084             Real* zki = z + i; zkj = z + j;
00085             k = i;
00086             if (k) for (;;)
00087                { *zkj -= g * (*zki); if (!(--k)) break; zkj += n; zki += n; }
00088          }
00089       }
00090       Real* zij = z + i*n; Real* zji = z + i;
00091       int j = i;
00092       if (j) for (;;)
00093          { *zij++ = 0.0; *zji = 0.0; if (!(--j)) break; zji += n; }
00094       D.element(i) = *zij; *zij = 1.0;
00095    }
00096 }
00097 
00098 static void tql2(DiagonalMatrix& D, DiagonalMatrix& E, Matrix& Z)
00099 {
00100    Tracer et("Evalue(tql2)");
00101    REPORT
00102    Real eps = FloatingPointPrecision::Epsilon();
00103    int n = D.Nrows(); Real* z = Z.Store(); int l;
00104    for (l=1; l<n; l++) E.element(l-1) = E.element(l);
00105    Real b = 0.0; Real f = 0.0; E.element(n-1) = 0.0;
00106    for (l=0; l<n; l++)
00107    {
00108       int i,j;
00109       Real& dl = D.element(l); Real& el = E.element(l);
00110       Real h = eps * ( fabs(dl) + fabs(el) );
00111       if (b < h) { REPORT b = h; }
00112       int m;
00113       for (m=l; m<n; m++) if (fabs(E.element(m)) <= b) break;
00114       bool test = false;
00115       for (j=0; j<30; j++)
00116       {
00117          if (m==l) { REPORT test = true; break; }
00118          Real& dl1 = D.element(l+1);
00119          Real g = dl; Real p = (dl1-g) / (2.0*el); Real r = sqrt(p*p + 1.0);
00120          dl = el / (p < 0.0 ? p-r : p+r); Real h = g - dl; f += h;
00121          Real* dlx = &dl1; i = n-l-1; while (i--) *dlx++ -= h;
00122 
00123          p = D.element(m); Real c = 1.0; Real s = 0.0;
00124          for (i=m-1; i>=l; i--)
00125          {
00126             Real ei = E.element(i); Real di = D.element(i);
00127             Real& ei1 = E.element(i+1);
00128             g = c * ei; h = c * p;
00129             if ( fabs(p) >= fabs(ei))
00130             {
00131                REPORT
00132                c = ei / p; r = sqrt(c*c + 1.0);
00133                ei1 = s*p*r; s = c/r; c = 1.0/r;
00134             }
00135             else
00136             {
00137                REPORT
00138                c = p / ei; r = sqrt(c*c + 1.0);
00139                ei1 = s * ei * r; s = 1.0/r; c /= r;
00140             }
00141             p = c * di - s*g; D.element(i+1) = h + s * (c*g + s*di);
00142 
00143             Real* zki = z + i; Real* zki1 = zki + 1; int k = n;
00144             if (k) for (;;)
00145             {
00146                REPORT
00147                h = *zki1; *zki1 = s*(*zki) + c*h; *zki = c*(*zki) - s*h;
00148                if (!(--k)) break;
00149                zki += n; zki1 += n;
00150             }
00151          }
00152          el = s*p; dl = c*p;
00153          if (fabs(el) <= b) { REPORT; test = true; break; }
00154       }
00155       if (!test) Throw ( ConvergenceException(D) );
00156       dl += f;
00157    }
00158 /*
00159    for (int i=0; i<n; i++)
00160    {
00161       int k = i; Real p = D.element(i);
00162       for (int j=i+1; j<n; j++)
00163          { if (D.element(j) < p) { k = j; p = D.element(j); } }
00164       if (k != i)
00165       {
00166          D.element(k) = D.element(i); D.element(i) = p; int j = n;
00167          Real* zji = z + i; Real* zjk = z + k;
00168          if (j) for(;;)
00169          {
00170             p = *zji; *zji = *zjk; *zjk = p;
00171             if (!(--j)) break;
00172             zji += n; zjk += n;
00173          }
00174       }
00175    }
00176 */
00177 }
00178 
00179 static void tred3(const SymmetricMatrix& X, DiagonalMatrix& D,
00180    DiagonalMatrix& E, SymmetricMatrix& A)
00181 {
00182    Tracer et("Evalue(tred3)");
00183    REPORT
00184    Real tol =
00185       FloatingPointPrecision::Minimum()/FloatingPointPrecision::Epsilon();
00186    int n = X.Nrows(); A = X; D.ReSize(n); E.ReSize(n);
00187    Real* ei = E.Store() + n;
00188    for (int i = n-1; i >= 0; i--)
00189    {
00190       Real h = 0.0; Real f = - FloatingPointPrecision::Maximum();
00191       Real* d = D.Store(); Real* a = A.Store() + (i*(i+1))/2; int k = i;
00192       while (k--) { f = *a++; *d++ = f; h += square(f); }
00193       if (h <= tol) { REPORT *(--ei) = 0.0; h = 0.0; }
00194       else
00195       {
00196          REPORT
00197          Real g = sign(-sqrt(h), f); *(--ei) = g; h -= f*g;
00198          f -= g; *(d-1) = f; *(a-1) = f; f = 0.0;
00199          Real* dj = D.Store(); Real* ej = E.Store(); int j;
00200          for (j = 0; j < i; j++)
00201          {
00202             Real* dk = D.Store(); Real* ak = A.Store()+(j*(j+1))/2;
00203             Real g = 0.0; k = j;
00204             while (k--)  g += *ak++ * *dk++;
00205             k = i-j; int l = j; 
00206             if (k) for (;;) { g += *ak * *dk++; if (!(--k)) break; ak += ++l; }
00207             g /= h; *ej++ = g; f += g * *dj++;
00208          }  
00209          Real hh = f / (2 * h); Real* ak = A.Store();
00210          dj = D.Store(); ej = E.Store();
00211          for (j = 0; j < i; j++)
00212          {
00213             f = *dj++; g = *ej - hh * f; *ej++ = g;
00214             Real* dk = D.Store(); Real* ek = E.Store(); k = j+1;
00215             while (k--) { *ak++ -= (f * *ek++ + g * *dk++); }
00216          }
00217       }
00218       *d = *a; *a = h;
00219    }
00220 }
00221 
00222 static void tql1(DiagonalMatrix& D, DiagonalMatrix& E)
00223 {
00224    Tracer et("Evalue(tql1)");
00225    REPORT
00226    Real eps = FloatingPointPrecision::Epsilon();
00227    int n = D.Nrows(); int l;
00228    for (l=1; l<n; l++) E.element(l-1) = E.element(l);
00229    Real b = 0.0; Real f = 0.0; E.element(n-1) = 0.0;
00230    for (l=0; l<n; l++)
00231    {
00232       int i,j;
00233       Real& dl = D.element(l); Real& el = E.element(l);
00234       Real h = eps * ( fabs(dl) + fabs(el) );
00235       if (b < h) b = h;
00236       int m;
00237       for (m=l; m<n; m++) if (fabs(E.element(m)) <= b) break;
00238       bool test = false;
00239       for (j=0; j<30; j++)
00240       {
00241          if (m==l) { REPORT test = true; break; }
00242          Real& dl1 = D.element(l+1);
00243          Real g = dl; Real p = (dl1-g) / (2.0*el); Real r = sqrt(p*p + 1.0);
00244          dl = el / (p < 0.0 ? p-r : p+r); Real h = g - dl; f += h;
00245          Real* dlx = &dl1; i = n-l-1; while (i--) *dlx++ -= h;
00246 
00247          p = D.element(m); Real c = 1.0; Real s = 0.0;
00248          for (i=m-1; i>=l; i--)
00249          {
00250             Real ei = E.element(i); Real di = D.element(i);
00251             Real& ei1 = E.element(i+1);
00252             g = c * ei; h = c * p;
00253             if ( fabs(p) >= fabs(ei))
00254             {
00255                REPORT
00256                c = ei / p; r = sqrt(c*c + 1.0);
00257                ei1 = s*p*r; s = c/r; c = 1.0/r;
00258             }
00259             else
00260             {
00261                REPORT
00262                c = p / ei; r = sqrt(c*c + 1.0);
00263                ei1 = s * ei * r; s = 1.0/r; c /= r;
00264             }
00265             p = c * di - s*g; D.element(i+1) = h + s * (c*g + s*di);
00266          }
00267          el = s*p; dl = c*p;
00268          if (fabs(el) <= b) { REPORT test = true; break; }
00269       }
00270       if (!test) Throw ( ConvergenceException(D) );
00271       Real p = dl + f;
00272       test = false;
00273       for (i=l; i>0; i--)
00274       {
00275          if (p < D.element(i-1)) { REPORT D.element(i) = D.element(i-1); }
00276          else { REPORT test = true; break; }
00277       }
00278       if (!test) i=0;
00279       D.element(i) = p;
00280    }
00281 }
00282 
00283 void EigenValues(const SymmetricMatrix& A, DiagonalMatrix& D, Matrix& Z)
00284 { REPORT DiagonalMatrix E; tred2(A, D, E, Z); tql2(D, E, Z); SortSV(D,Z,true); }
00285 
00286 void EigenValues(const SymmetricMatrix& X, DiagonalMatrix& D)
00287 { REPORT DiagonalMatrix E; SymmetricMatrix A; tred3(X,D,E,A); tql1(D,E); }
00288 
00289 void EigenValues(const SymmetricMatrix& X, DiagonalMatrix& D,
00290    SymmetricMatrix& A)
00291 { REPORT DiagonalMatrix E; tred3(X,D,E,A); tql1(D,E); }
00292 
00293 
00294 #ifdef use_namespace
00295 }
00296 #endif
00297 


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Author(s): Todd Hester
autogenerated on Thu Jun 6 2019 22:00:13