/**
Convert PSD into time series.*/
dmat* psd2time(const dmat *psdin, rand_t *rstat, double dt, int nstepin){
if(!psdin){
error("psdin cannot be null\n");
}
long nstep=nextpow2(nstepin);
double df=1./(dt*nstep);
dmat *fs=dlinspace(0, df, nstep);
dmat *psd=NULL;
if(psdin->ny==1){//[alpha, beta, fmin, fmax] discribes power law with cut on/off freq.
psd=dnew(nstep, 1);
double alpha=psdin->p[0];
double beta=psdin->p[1];
long i0=1, imax=nstep;
if(psdin->nx>2){
i0=(long)round(psdin->p[2]/df);
if(i0<1) i0=1;
}
if(psdin->nx>3){
imax=(long)round(psdin->p[3]/df);
}
info("fmin=%g, fmax=%g, df=%g, i0=%ld, imax=%ld\n",
psdin->p[2], psdin->p[3], df, i0, imax);
for(long i=i0; i<imax; i++){
psd->p[i]=beta*pow(i*df, alpha);
}
}else if(psdin->ny==2){
if(psdin->nx<2){
error("Invalid PSD\n");
}
psd=dinterp1(psdin, 0, fs, 1e-40);
psd->p[0]=0;/*disable pistion. */
}else{
error("psdin is invalid format.\n");
}
cmat *wshat=cnew(nstep, 1);
//cfft2plan(wshat, -1);
for(long i=0; i<nstep; i++){
wshat->p[i]=sqrt(psd->p[i]*df)*COMPLEX(randn(rstat), randn(rstat));
}
cfft2(wshat, -1);
dmat *out=NULL;
creal2d(&out, 0, wshat, 1);
cfree(wshat);
dfree(psd);
dfree(fs);
dresize(out, nstepin, 1);
return out;
}
static void test_stfun(){
rand_t rstat;
int seed=4;
double r0=0.2;
double dx=1./16;
long N=32;
long nx=N;
long ny=N;
long nframe=500;
seed_rand(&rstat, seed);
if(L0<9000){
dmat *rr=dlinspace(0, N*dx, N);
dmat *covvk=turbcov(rr, sqrt(2)*N*dx, r0, L0);
writebin(covvk, "cov_vk");
dfree(rr);
dfree(covvk);
}
/* return; */
{
map_t *atm=mapnew(nx+1, ny+1, dx, dx,NULL);
stfun_t *data=stfun_init(nx, ny, NULL);
zfarr *save=zfarr_init(nframe, 1, "fractal_atm.bin");
for(long i=0; i<nframe; i++){
for(long j=0; j<(nx+1)*(ny+1); j++){
atm->p[j]=randn(&rstat);
}
fractal_do((dmat*)atm, dx, r0,L0,ninit);
stfun_push(data, (dmat*)atm);
zfarr_dmat(save, i, (dmat*)atm);
if(i%100==0)
info("%ld of %ld\n", i, nframe);
}
zfarr_close(save);
dmat *st=stfun_finalize(data);
writebin(st, "stfun_fractal.bin");
ddraw("fractal", st, NULL,NULL, "Atmosphere","x","y","stfun");
}
/*exit(0); */
{
stfun_t *data=stfun_init(nx, ny, NULL);
dmat *spect=turbpsd(nx, ny, dx, r0, 100, 0, 0.5);
cmat *atm=cnew(nx, ny);
//cfft2plan(atm, -1);
dmat *atmr=dnew(atm->nx, atm->ny);
dmat *atmi=dnew(atm->nx, atm->ny);
spect->p[0]=0;
for(long ii=0; ii<nframe; ii+=2){
for(long i=0; i<atm->nx*atm->ny; i++){
atm->p[i]=COMPLEX(randn(&rstat), randn(&rstat))*spect->p[i];
}
cfft2(atm, -1);
for(long i=0; i<atm->nx*atm->ny; i++){
atmr->p[i]=creal(atm->p[i]);
atmi->p[i]=cimag(atm->p[i]);
}
stfun_push(data, atmr);
stfun_push(data, atmi);
if(ii%100==0)
info("%ld of %ld\n", ii, nframe);
}
dmat *st=stfun_finalize(data);
writebin(st, "stfun_fft.bin");
ddraw("fft", st, NULL,NULL, "Atmosphere","x","y","stfun");
}
}
