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EVALUE.CPP Source File
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EVALUE.CPP

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

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