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qpms/qpms/beyn.c

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/*
* This file was originally part of SCUFF-EM by M. T. Homer Reid.
* Modified by Kristian Arjas and Marek Nečada to work without libhmat and libhrutil.
*
* SCUFF-EM is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* SCUFF-EM is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define STATIC_ASSERT(COND,MSG) typedef char static_assertion_##MSG[(COND)?1:-1]
#include <complex.h>
#include <lapacke.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>
#include "qpms_error.h"
// Maybe GSL works?
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_complex_math.h>
#include <gsl/gsl_linalg.h>
#include <gsl/gsl_blas.h>
#include <gsl/gsl_eigen.h>
#include <beyn.h>
STATIC_ASSERT((sizeof(lapack_complex_double) == sizeof(gsl_complex)), lapack_and_gsl_complex_must_be_consistent);
// Uniformly random number between -2 and 2
gsl_complex zrandN(){
double a = (rand()*4.0/RAND_MAX) - 2;
double b = (rand()*4.0/RAND_MAX) - 2;
return gsl_complex_rect(a, b);
}
/***************************************************************/
/***************************************************************/
/***************************************************************/
BeynSolver *CreateBeynSolver(int M, int L)
{
BeynSolver *Solver= (BeynSolver *)malloc(sizeof(*Solver));
Solver->M = M;
Solver->L = L;
QPMS_ENSURE(L <= M, "We expect L <= M, but we got L = %d, M = %d ", L, M);
#if 0
int MLMax = (M>L) ? M : L;
#endif
int MLMin = (M<L) ? M : L;
// storage for eigenvalues and eigenvectors
Solver->Eigenvalues = gsl_vector_complex_calloc(L);
Solver->EVErrors = gsl_vector_complex_calloc(L);
Solver->Residuals = gsl_vector_calloc(L);
Solver->Eigenvectors = gsl_matrix_complex_calloc(M, L);
// storage for singular values, random VHat matrix, etc. used in algorithm
Solver->A0 = gsl_matrix_complex_calloc(M,L);
Solver->A1 = gsl_matrix_complex_calloc(M,L);
Solver->A0Coarse = gsl_matrix_complex_calloc(M,L);
Solver->A1Coarse = gsl_matrix_complex_calloc(M,L);
Solver->MInvVHat = gsl_matrix_complex_calloc(M,L);
Solver->VHat = gsl_matrix_complex_calloc(M,L);
Solver->Sigma = gsl_vector_calloc(MLMin);
ReRandomize(Solver,(unsigned)time(NULL));
#if 0
// internal workspace: need storage for 2 MxL matrices
// plus 3 LxL matrices
#define MLBUFFERS 2
#define LLBUFFERS 3
size_t ML = MLMax*L, LL = L*L;
#endif
return Solver;
}
/***************************************************************/
/***************************************************************/
/***************************************************************/
void DestroyBeynSolver(BeynSolver *Solver)
{
gsl_vector_complex_free(Solver->Eigenvalues);
gsl_vector_complex_free(Solver->EVErrors);
gsl_matrix_complex_free(Solver->Eigenvectors);
gsl_matrix_complex_free(Solver->A0);
gsl_matrix_complex_free(Solver->A1);
gsl_matrix_complex_free(Solver->A0Coarse);
gsl_matrix_complex_free(Solver->A1Coarse);
gsl_matrix_complex_free(Solver->MInvVHat);
gsl_vector_free(Solver->Sigma);
gsl_vector_free(Solver->Residuals);
gsl_matrix_complex_free(Solver->VHat);
free(Solver);
}
/***************************************************************/
/***************************************************************/
/***************************************************************/
void ReRandomize(BeynSolver *Solver, unsigned int RandSeed)
{
if (RandSeed==0)
RandSeed=time(0);
srandom(RandSeed);
gsl_matrix_complex *VHat=Solver->VHat;
for(int nr=0; nr<VHat->size1; nr++)
for(int nc=0; nc<VHat->size2; nc++)
gsl_matrix_complex_set(VHat,nr,nc,zrandN());
}
/***************************************************************/
/* perform linear-algebra manipulations on the A0 and A1 */
/* matrices (obtained via numerical quadrature) to extract */
/* eigenvalues and eigenvectors */
/***************************************************************/
int ProcessAMatrices(BeynSolver *Solver, beyn_function_M_t M_function,
void *Params,
gsl_matrix_complex *A0, gsl_matrix_complex *A1, double complex z0,
gsl_vector_complex *Eigenvalues, gsl_matrix_complex *Eigenvectors)
{
int M = Solver->M;
int L = Solver->L;
gsl_vector *Sigma = Solver->Sigma;
int Verbose = 0;//CheckEnv("SCUFF_BEYN_VERBOSE");
double RankTol=1.0e-4; //CheckEnv("SCUFF_BEYN_RANK_TOL",&RankTol);
double ResTol=0.0; // CheckEnv("SCUFF_BEYN_RES_TOL",&ResTol);
// A0 -> V0Full * Sigma * W0TFull'
printf(" Beyn: computing SVD...\n");
gsl_matrix_complex* V0Full = gsl_matrix_complex_calloc(M,L);
gsl_matrix_complex_memcpy(V0Full,A0);
gsl_matrix_complex* W0TFull = gsl_matrix_complex_calloc(L,L);
//A0->SVD(Sigma, &V0Full, &W0TFull);
QPMS_ENSURE(Sigma->stride == 1, "Sigma vector stride must be 1 for LAPACKE_zgesdd, got %zd.", Sigma->stride);
// FIXME not supported by GSL; use LAPACKE_zgesdd
//gsl_linalg_complex_SV_decomp(V0Full, W0TFull, Sigma, work);
QPMS_ENSURE_SUCCESS(LAPACKE_zgesdd(LAPACK_ROW_MAJOR, // A = U*Σ*conjg(V')
'O' /*jobz, 'O' overwrites a with U and saves conjg(V') in vt if m >= n, i.e. if M >= L, which holds*/,
V0Full->size1 /* m, number of rows */,
V0Full->size2 /* n, number of columns */,
(lapack_complex_double *)(V0Full->data) /*a*/,
V0Full->tda /*lda*/,
Sigma->data /*s*/,
NULL /*u; not used*/,
0 /*ldu; not used*/,
(lapack_complex_double *)W0TFull->data /*vt*/,
W0TFull->tda /*ldvt*/
));
// compute effective rank K (number of eigenvalue candidates)
int K=0;
for(int k=0; k<Sigma->size /* this is L, actually */; k++)
{ if (Verbose) printf("Beyn: SV(%i)=%e",k,gsl_vector_get(Sigma, k));
if (gsl_vector_get(Sigma, k) > RankTol )
K++;
}
printf(" Beyn: %i/%i relevant singular values\n",K,L);
if (K==0)
{ printf("no singular values found in Beyn eigensolver\n");
return 0;
}
// set V0, W0T = matrices of first K right, left singular vectors
gsl_matrix_complex *V0 = gsl_matrix_complex_alloc(M,K);
gsl_matrix_complex *W0T= gsl_matrix_complex_alloc(K,L);
gsl_vector_complex *TempM = gsl_vector_complex_calloc(M);
gsl_vector_complex *TempL = gsl_vector_complex_calloc(L);
for(int k=0; k<K; k++){
// It should be rows and cols like this, right..?
gsl_matrix_complex_get_row(TempM, V0Full,k);
gsl_matrix_complex_set_row(V0, k, TempM);
gsl_matrix_complex_get_col(TempL,W0TFull,k);
gsl_matrix_complex_set_col(W0T,k, TempL);
}
gsl_matrix_complex_free(V0Full);
gsl_matrix_complex_free(W0TFull);
gsl_vector_complex_free(TempM);
gsl_vector_complex_free(TempL);
// B <- V0' * A1 * W0 * Sigma^-1
gsl_matrix_complex *TM2 = gsl_matrix_complex_calloc(K,L);
gsl_matrix_complex *B = gsl_matrix_complex_calloc(K,K);
printf(" Multiplying V0*A1->TM...\n");
//V0.Multiply(A1, &TM2, "--transA C"); // TM2 <- V0' * A1
const gsl_complex one = gsl_complex_rect(1,0);
const gsl_complex zero = gsl_complex_rect(0,0);
gsl_blas_zgemm(CblasConjTrans, CblasNoTrans, one,
V0, A1, zero, TM2);
printf(" Multiplying TM*W0T->B...\n");
//TM2.Multiply(&W0T, &B, "--transB C"); // B <- TM2 * W0
gsl_blas_zgemm(CblasNoTrans, CblasTrans, one,
TM2, W0T, zero, B);
gsl_matrix_complex_free(W0T);
gsl_matrix_complex_free(TM2);
printf(" Scaling B <- B*Sigma^{-1}\n");
gsl_vector_complex *tmp = gsl_vector_complex_calloc(K);
for(int i = 0; i < K; i++){
gsl_matrix_complex_get_col(tmp, B, i);
gsl_vector_complex_scale(tmp, gsl_complex_rect(1.0/gsl_vector_get(Sigma,i), 0));
gsl_matrix_complex_set_col(B,i,tmp);
}
gsl_vector_complex_free(tmp);
//for(int m=0; m<K; m++) // B <- B * Sigma^{-1}
// for(int n=0; n<K; n++)
// B.ScaleEntry(m,n,1.0/Sigma->GetEntry(n));
// B -> S*Lambda*S'
printf(" Eigensolving (%i,%i)\n",K,K);
gsl_vector_complex *Lambda = gsl_vector_complex_alloc(K); // Eigenvalues
gsl_matrix_complex *S = gsl_matrix_complex_alloc(K,K); // Eigenvectors
// FIXME general complex eigensystems not supported by GSL (use LAPACKE_zgee?)
//gsl_eigen_genv_workspace * W = gsl_eigen_genv_alloc(K);
//gsl_eigen_genv(B, Eye, alph, beta, S,W);
//gsl_eigen_genv_free(W);
QPMS_ENSURE(Sigma->stride == 1, "Sigma vector stride must be 1 for LAPACKE_zgesdd, got %zd.", Sigma->stride);
QPMS_ENSURE(Lambda->stride == 1, "Lambda vector stride must be 1 for LAPACKE_zgesdd, got %zd.", Sigma->stride);
QPMS_ENSURE_SUCCESS(LAPACKE_zgeev(
LAPACK_ROW_MAJOR,
'N' /* jobvl; don't compute left eigenvectors */,
'V' /* jobvr; do compute right eigenvectors */,
K /* n */,
(lapack_complex_double *)(S->data) /* a */,
S->tda /* lda */,
(lapack_complex_double *) Lambda->data /* w */,
NULL /* vl */,
0 /* ldvl */,
(lapack_complex_double *)(B->data)/* vr */,
B->tda/* ldvr */
));
//B.NSEig(&Lambda, &S);
// V0S <- V0*S
printf("Multiplying V0*S...\n");
gsl_matrix_complex *V0S = gsl_matrix_complex_alloc(M, K);
QPMS_ENSURE_SUCCESS(gsl_blas_zgemm(CblasNoTrans, CblasNoTrans,
one, V0, S, zero, V0S));
int KRetained = 0;
gsl_matrix_complex *Mmat = gsl_matrix_complex_alloc(M,M);
gsl_vector_complex *MVk = gsl_vector_complex_alloc(M);
for (int k = 0; k < K; ++k) {
const gsl_complex zgsl = gsl_complex_add(gsl_complex_rect(creal(z0), cimag(z0)), gsl_vector_complex_get(Lambda, k));
const complex double z = GSL_REAL(zgsl) + I*GSL_IMAG(zgsl);
gsl_vector_complex_const_view Vk = gsl_matrix_complex_const_column(V0S, k);
double residual = 0;
if(ResTol > 0) {
QPMS_ENSURE_SUCCESS(M_function(Mmat, z, Params));
QPMS_ENSURE_SUCCESS(gsl_blas_zgemv(CblasNoTrans, one, Mmat, &(Vk.vector), zero, MVk));
residual = gsl_blas_dznrm2(MVk);
if (Verbose) printf("Beyn: Residual(%i)=%e\n",k,residual);
}
if (ResTol > 0 && residual > ResTol) continue;
gsl_vector_complex_set(Eigenvalues, KRetained, zgsl);
if(Eigenvectors) {
gsl_matrix_complex_set_col(Eigenvectors, KRetained, &(Vk.vector));
gsl_vector_set(Solver->Residuals, KRetained, residual);
}
++KRetained;
}
gsl_matrix_complex_free(V0S);
gsl_matrix_complex_free(Mmat);
gsl_vector_complex_free(MVk);
gsl_matrix_complex_free(S);
gsl_vector_complex_free(Lambda);
return KRetained;
}
/***************************************************************/
/***************************************************************/
/***************************************************************/
int BeynSolve(BeynSolver *Solver, beyn_function_M_t M_function,
beyn_function_M_inv_Vhat_t M_inv_Vhat_function, void *Params,
double complex z0, double Rx, double Ry, int N)
{
/***************************************************************/
/* force N to be even so we can simultaneously evaluate */
/* the integral with N/2 quadrature points */
/***************************************************************/
if ( (N%2)==1 ) N++;
/*if (Rx==Ry)
printf("Applying Beyn method with z0=%s,R=%e,N=%i...\n",z2s(z0),Rx,N);
else
printf("Applying Beyn method with z0=%s,Rx=%e,Ry=%e,N=%i...\n",z2s(z0),Rx,Ry,N);
*/
const int M = Solver->M;
const int L = Solver->L;
gsl_matrix_complex *A0 = Solver->A0;
gsl_matrix_complex *A1 = Solver->A1;
gsl_matrix_complex *A0Coarse = Solver->A0Coarse;
gsl_matrix_complex *A1Coarse = Solver->A1Coarse;
gsl_matrix_complex *MInvVHat = Solver->MInvVHat;
gsl_matrix_complex *VHat = Solver->VHat;
/***************************************************************/
/* evaluate contour integrals by numerical quadrature to get */
/* A0 and A1 matrices */
/***************************************************************/
gsl_matrix_complex_set_zero(A0);
gsl_matrix_complex_set_zero(A1);
gsl_matrix_complex_set_zero(A0Coarse);
gsl_matrix_complex_set_zero(A1Coarse);
double DeltaTheta = 2.0*M_PI / ((double)N);
printf(" Evaluating contour integral (%i points)...\n",N);
for(int n=0; n<N; n++)
{
double Theta = ((double)n)*DeltaTheta;
double CT = cos(Theta), ST=sin(Theta);
gsl_complex z1 = gsl_complex_rect(Rx*CT, Ry*ST);
gsl_complex dz = gsl_complex_rect(Ry*CT/((double)N),(Rx*ST/((double)N)));
double complex zz = Rx*CT + Ry*ST*I;
//MInvVHat->Copy(VHat);
// Mitä varten tämä kopiointi on?
gsl_matrix_complex_memcpy(MInvVHat, VHat);
// Tän pitäis kutsua eval_WT
// Output ilmeisesti tallentuun neljänteen parametriin
if(M_inv_Vhat_function) {
QPMS_ENSURE_SUCCESS(M_inv_Vhat_function(MInvVHat, VHat, z0+zz, Params));
} else {
lapack_int *pivot;
gsl_matrix_complex *Mmat = gsl_matrix_complex_alloc(M,M);
QPMS_ENSURE_SUCCESS(M_function(Mmat, z0+zz, Params));
QPMS_CRASHING_MALLOC(pivot, sizeof(lapack_int) * M);
QPMS_ENSURE_SUCCESS(LAPACKE_zgetrf(LAPACK_ROW_MAJOR,
M /*m*/, M /*n*/,(lapack_complex_double *) Mmat->data /*a*/, Mmat->tda /*lda*/, pivot /*ipiv*/));
QPMS_ENSURE_SUCCESS(LAPACKE_zgetrs(LAPACK_ROW_MAJOR, 'N' /*trans*/,
M /*n*/, L/*nrhs*/, (lapack_complex_double *)Mmat->data /*a*/, Mmat->tda /*lda*/, pivot/*ipiv*/,
(lapack_complex_double *)VHat->data /*b*/, VHat->tda/*ldb*/));
free(pivot);
gsl_matrix_complex_free(Mmat);
}
//UserFunc(z0+zz, Params, VHat, MInvVHat);
gsl_matrix_complex_scale(MInvVHat, dz);
gsl_matrix_complex_add(A0, MInvVHat);
if((n%2)==0) {
gsl_matrix_complex_add(A0Coarse, MInvVHat);
gsl_matrix_complex_add(A0Coarse, MInvVHat);
}
gsl_matrix_complex_scale(MInvVHat, z1);
gsl_matrix_complex_add(A1, MInvVHat);
if((n%2)==0) {
gsl_matrix_complex_add(A1Coarse, MInvVHat);
gsl_matrix_complex_add(A1Coarse, MInvVHat);
}
}
gsl_vector_complex *Eigenvalues = Solver->Eigenvalues;
//gsl_vector_complex *EVErrors = Solver->EVErrors;
gsl_matrix_complex *Eigenvectors = Solver->Eigenvectors;
int K = ProcessAMatrices(Solver, M_function, Params, A0, A1, z0, Eigenvalues, Eigenvectors);
//int KCoarse = ProcessAMatrices(Solver, UserFunc, Params, A0Coarse, A1Coarse, z0, EVErrors, Eigenvectors);
// Log("{K,KCoarse}={%i,%i}",K,KCoarse);
/*
for(int k=0; k<EVErrors->N && k<Eigenvalues->N; k++)
{ EVErrors->ZV[k] -= Eigenvalues->ZV[k];
EVErrors->ZV[k] = cdouble( fabs(real(EVErrors->ZV[k])),
fabs(imag(EVErrors->ZV[k]))
);
}
*/
return K;
}
/***************************************************************/
/***************************************************************/
/***************************************************************/
/*
int BeynSolve(BeynSolver *Solver,
BeynFunction UserFunction, void *Params,
cdouble z0, double R, int N)
{ return BeynSolve(Solver, UserFunction, Params, z0, R, R, N); }
*/
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