#include "ltfat.h"
#include "ltfat/types.h"
#include "ltfat/macros.h"

#include "ltfat/thirdparty/fftw3.h"

#ifndef GGA_UNROLL
#   define GGA_UNROLL 8
#endif

struct LTFAT_NAME(gga_plan_struct)
{
    LTFAT_REAL* cos_term;
    LTFAT_COMPLEX* cc_term;
    LTFAT_COMPLEX* cc2_term;
    ltfat_int M;
    ltfat_int L;
};

struct LTFAT_NAME(chzt_plan_struct)
{
    LTFAT_COMPLEX* fbuffer;
    LTFAT_COMPLEX* W2;
    LTFAT_COMPLEX* Wo;
    LTFAT_COMPLEX* chirpF;
    /* LTFAT_FFTW(plan) plan; */
    /* LTFAT_FFTW(plan) plan2; */
    LTFAT_NAME_REAL(fft_plan)* plan;
    LTFAT_NAME_REAL(ifft_plan)* plan2;
    ltfat_int L;
    ltfat_int K;
    ltfat_int Lfft;
};


LTFAT_API LTFAT_NAME(gga_plan)
LTFAT_NAME(gga_init)(const LTFAT_REAL* indVecPtr, ltfat_int M,
                     ltfat_int L)
{
    LTFAT_REAL* cos_term = LTFAT_NAME_REAL(malloc)(M);
    LTFAT_COMPLEX* cc_term = LTFAT_NAME_COMPLEX(malloc)(M);
    LTFAT_COMPLEX* cc2_term = LTFAT_NAME_COMPLEX(malloc)(M);

    LTFAT_REAL pik_term_pre = (LTFAT_REAL) (2.0 * M_PI / ((double) L));
    LTFAT_COMPLEX cc2_pre = -I * (LTFAT_REAL)(L - 1);
    LTFAT_COMPLEX cc_pre =  -I * (LTFAT_REAL)(L);

    for (ltfat_int m = 0; m < M; m++)
    {
        LTFAT_REAL pik_term = pik_term_pre * indVecPtr[m];
        cos_term[m] = (LTFAT_REAL) ( cos(pik_term) * 2.0 );
        cc_term[m] = (LTFAT_COMPLEX) exp(cc_pre * pik_term);
        cc2_term[m] = (LTFAT_COMPLEX) exp(cc2_pre * pik_term);
    }

    // This is workaround for defining constant elements of the struct.
    /* struct LTFAT_NAME(gga_plan_struct) plan_tmp = */
    /* {.cos_term = cos_term, .cc_term = cc_term, .cc2_term = cc2_term, .M = M, .L = L}; */

    LTFAT_NAME(gga_plan) plan = (LTFAT_NAME(gga_plan)) ltfat_malloc(sizeof * plan);
    plan->cos_term = cos_term; plan->cc_term = cc_term;
    plan->cc2_term = cc2_term; plan->M = M; plan->L = L;

    /* memcpy(plan, &plan_tmp, sizeof * plan); */

    return plan;
}

LTFAT_API
void LTFAT_NAME(gga_done)(LTFAT_NAME(gga_plan) plan)
{
    LTFAT_SAFEFREEALL((void*)plan->cos_term,
                      (void*)plan->cc_term,
                      (void*)plan->cc2_term);
    ltfat_free(plan);
}


LTFAT_API
void LTFAT_NAME(gga_execute)(LTFAT_NAME(gga_plan) p,
                             const LTFAT_TYPE* fPtr,
                             ltfat_int W,
                             LTFAT_COMPLEX* cPtr)
{
#ifndef GGA_UNROLL

    for (ltfat_int w = 0; w < W; w++)
    {
        LTFAT_COMPLEX* cPtrTmp = (LTFAT_COMPLEX*) cPtr + w * p.M;

        for (ltfat_int m = 0; m < p.M; m++)
        {
            LTFAT_TYPE s0 =  0.0;
            LTFAT_TYPE s1 =  0.0;
            LTFAT_TYPE s2 =  0.0;
            LTFAT_TYPE* fPtrTmp = (LTFAT_TYPE*) fPtr + w * p.L;

            for (ltfat_int ii = 0; ii < p.L - 1; ii++)
            {
                s0 = *fPtrTmp++ + p.cos_term[m] * s1 - s2;
                s2 = s1;
                s1 = s0;
            }
            s0 = *fPtrTmp + p.cos_term[m] * s1 - s2;

            *cPtrTmp++ = (s0 * p.cc2_term[m] - s1 * p.cc_term[m]);
        }
    }
#else
    for (ltfat_int w = 0; w < W; w++)
    {
        LTFAT_COMPLEX* cPtrTmp = (LTFAT_COMPLEX*) cPtr + w * p->M;
        ltfat_int unrollRem = p->M % GGA_UNROLL;

        const LTFAT_REAL* cos_term = p->cos_term;
        const LTFAT_COMPLEX* cc_term = p->cc_term;
        const LTFAT_COMPLEX* cc2_term = p->cc2_term;
//#pragma omp parallel for
        for (ltfat_int m = 0; m < p->M - unrollRem; m += GGA_UNROLL)
        {
            LTFAT_TYPE s0[GGA_UNROLL] = {0};
            LTFAT_TYPE s1[GGA_UNROLL] = {0};
            LTFAT_TYPE s2[GGA_UNROLL] = {0};

            /* for (ltfat_int un = 0; un < GGA_UNROLL; un++) */
            /* { */
            /*     s0[un] = 0.0; */
            /*     s1[un] = 0.0; */
            /*     s2[un] = 0.0; */
            /* } */

            LTFAT_TYPE* fPtrTmp = (LTFAT_TYPE*) fPtr + w * p->L;

            for (ltfat_int ii = 0; ii < p->L - 1; ii++)
            {
                for (ltfat_int un = 0; un < GGA_UNROLL; un++)
                {
                    s0[un] = *fPtrTmp + cos_term[un] * s1[un] - s2[un];
                    s2[un] = s1[un];
                    s1[un] = s0[un];
                }
                fPtrTmp++;
            }
            for (ltfat_int un = 0; un < GGA_UNROLL; un++)
            {
                s0[un] = *fPtrTmp + cos_term[un] * s1[un] - s2[un];
                cPtrTmp[m + un] = (s0[un] * cc2_term[un] - s1[un] * cc_term[un]);
            }
            cos_term += GGA_UNROLL;
            cc_term += GGA_UNROLL;
            cc2_term += GGA_UNROLL;
        }

        ltfat_int m = p->M - unrollRem;


        LTFAT_TYPE s0[GGA_UNROLL] = {0};
        LTFAT_TYPE s1[GGA_UNROLL] = {0};
        LTFAT_TYPE s2[GGA_UNROLL] = {0};

        /* for (ltfat_int un = 0; un < unrollRem; un++) */
        /* { */
        /*     s0[un] = 0.0; */
        /*     s1[un] = 0.0; */
        /*     s2[un] = 0.0; */
        /* } */

        LTFAT_TYPE* fPtrTmp = (LTFAT_TYPE*) fPtr + w * p->L;

        for (ltfat_int ii = 0; ii < p->L - 1; ii++)
        {
            for (ltfat_int un = 0; un < unrollRem; un++)
            {
                s0[un] = *fPtrTmp + cos_term[un] * s1[un] - s2[un];
                s2[un] = s1[un];
                s1[un] = s0[un];
            }
            fPtrTmp++;
        }

        for (ltfat_int un = 0; un < unrollRem; un++)
        {
            s0[un] = *fPtrTmp + cos_term[un] * s1[un] - s2[un];
            cPtrTmp[m + un] = (s0[un] * cc2_term[un] - s1[un] * cc_term[un]);
        }

    }
#endif
}



LTFAT_API
void LTFAT_NAME(gga)(const LTFAT_TYPE* fPtr, const LTFAT_REAL* indVecPtr,
                     ltfat_int L, ltfat_int W, ltfat_int M, LTFAT_COMPLEX* cPtr)
{
    LTFAT_NAME(gga_plan) p = LTFAT_NAME(gga_init)(indVecPtr, M, L);
    LTFAT_NAME(gga_execute)(p, fPtr, W, cPtr);
    LTFAT_NAME(gga_done)(p);
}



LTFAT_API void
LTFAT_NAME(chzt)(const LTFAT_TYPE* fPtr, ltfat_int L, ltfat_int W,
                 ltfat_int K, const LTFAT_REAL deltao, const LTFAT_REAL o,
                 LTFAT_COMPLEX* cPtr)
{
    LTFAT_NAME(chzt_plan) p = LTFAT_NAME(chzt_init)(K, L, deltao, o,
                              FFTW_ESTIMATE,
                              CZT_NEXTFASTFFT);

    LTFAT_NAME(chzt_execute)(p, fPtr, W, cPtr);

    LTFAT_NAME(chzt_done)(p);
}


LTFAT_API void
LTFAT_NAME(chzt_execute)(LTFAT_NAME(chzt_plan) p, const LTFAT_TYPE* fPtr,
                         ltfat_int W, LTFAT_COMPLEX* cPtr)
{

    ltfat_int L = p->L;
    ltfat_int K = p->K;
    ltfat_int Lfft = p->Lfft;
    LTFAT_COMPLEX* fbuffer = p->fbuffer;
    /* LTFAT_FFTW(plan) plan_f = p->plan; */
    /* LTFAT_FFTW(plan) plan_fi = p->plan2; */
    LTFAT_NAME_REAL(fft_plan)*   plan_f = p->plan;
    LTFAT_NAME_REAL(ifft_plan)* plan_fi = p->plan2;
    LTFAT_COMPLEX* W2 = p->W2;
    LTFAT_COMPLEX* Wo = p->Wo;
    LTFAT_COMPLEX* chirpF = p->chirpF;

    for (ltfat_int w = 0; w < W; w++)
    {
        memset(fbuffer, 0, Lfft * sizeof * fbuffer);
#ifdef LTFAT_COMPLEXTYPE
        memcpy(fbuffer, fPtr + w * L, L * sizeof * fbuffer);
#else
        LTFAT_NAME_REAL(real2complex_array)(fPtr + w * L, L, fbuffer);
#endif
        //1) Premultiply by a chirp

        for (ltfat_int ii = 0; ii < L; ii++)
        {
            fbuffer[ii] *= Wo[ii];
        }

        // 2) FFT of input
        /* LTFAT_FFTW(execute)(plan_f); */
        LTFAT_NAME_REAL(fft_execute)(plan_f);

        // Frequency domain filtering
        for (ltfat_int ii = 0; ii < Lfft; ii++)
        {
            fbuffer[ii] *= chirpF[ii];
        }


        // Inverse FFT
        LTFAT_COMPLEX* fPtrTmp = fbuffer;
        /* LTFAT_FFTW(execute)(plan_fi); */
        LTFAT_NAME_REAL(ifft_execute)(plan_fi);

        // Final chirp multiplication and normalization
        LTFAT_COMPLEX* cPtrTmp = cPtr + w * K;
        for (ltfat_int ii = 0; ii < K; ii++)
        {
            cPtrTmp[ii] = fPtrTmp[ii] * W2[ii];
        }

    }

}

LTFAT_API LTFAT_NAME(chzt_plan)
LTFAT_NAME(chzt_init)(ltfat_int K, ltfat_int L, const LTFAT_REAL deltao,
                      const LTFAT_REAL o, const unsigned fftw_flags,
                      czt_ffthint hint)
{
    ltfat_int Lfft = L + K - 1;

    if (hint == CZT_NEXTPOW2)
        Lfft = ltfat_nextpow2(Lfft);
    else
        Lfft = ltfat_nextfastfft(Lfft);

    LTFAT_COMPLEX* fbuffer = LTFAT_NAME_COMPLEX(malloc)(Lfft);
    /* int Lfftint = (int) Lfft; */
    /* LTFAT_FFTW(plan) plan_f =  LTFAT_FFTW(plan_dft_1d)(Lfftint, */
    /*                            (LTFAT_FFTW(complex)*) fbuffer, */
    /*                            (LTFAT_FFTW(complex)*) fbuffer, */
    /*                            FFTW_FORWARD, fftw_flags); */
    /* LTFAT_FFTW(plan) plan_fi =  LTFAT_FFTW(plan_dft_1d)(Lfftint, */
    /*                             (LTFAT_FFTW(complex)*) fbuffer, */
    /*                             (LTFAT_FFTW(complex)*) fbuffer, */
    /*                             FFTW_BACKWARD, fftw_flags); */

    LTFAT_NAME_REAL(fft_plan)*   plan_f;
    LTFAT_NAME_REAL(ifft_plan)* plan_fi;
    LTFAT_NAME_REAL(fft_init)( Lfft, 1, fbuffer, fbuffer, fftw_flags, &plan_f);
    LTFAT_NAME_REAL(ifft_init)(Lfft, 1, fbuffer, fbuffer, fftw_flags, &plan_fi);

    // Pre and post chirp
    ltfat_int N = L > K ? L : K;
    LTFAT_COMPLEX* W2 = LTFAT_NAME_COMPLEX(malloc)(Lfft);
    LTFAT_COMPLEX* chirpF = LTFAT_NAME_COMPLEX(malloc)(Lfft);
    LTFAT_COMPLEX* Wo = LTFAT_NAME_COMPLEX(malloc)(L);


    for (ltfat_int ii = 0; ii < N; ii++)
    {
        W2[ii] = exp(-I * (LTFAT_REAL)( deltao * ii * ii / 2.0));
    }

    for (ltfat_int ii = 0; ii < L; ii++)
    {
        Wo[ii] = exp(-I * (LTFAT_REAL)( o * ii )) * W2[ii];
    }
    // Set the rest to zero
    memset(W2 + N, 0, (Lfft - N)*sizeof * W2);

    LTFAT_NAME_COMPLEX(conjugate_array)(W2, K, chirpF);
    LTFAT_NAME_COMPLEX(conjugate_array)(W2 + 1, L - 1, chirpF + Lfft - L + 1);
    LTFAT_NAME_COMPLEX(reverse_array)(chirpF + Lfft - L + 1, L - 1,
                                      chirpF + Lfft - L + 1);
    memset(chirpF + K, 0, (Lfft - (L + K - 1))*sizeof * chirpF);

    /* LTFAT_FFTW(execute_dft)(plan_f, (LTFAT_FFTW(complex)*) chirpF, */
    /*                         (LTFAT_FFTW(complex)*) chirpF); */
    LTFAT_NAME_REAL(fft_execute_newarray)(plan_f, chirpF, chirpF);

    for (ltfat_int ii = 0; ii < K; ii++)
    {
        W2[ii] = exp(-I * (LTFAT_REAL)(deltao * ii * ii / 2.0))
                 / (( LTFAT_REAL) Lfft);
    }

    /*
    We could have shrinked the W2 to length K here.
    */
    /* struct LTFAT_NAME(chzt_plan_struct) p_struct = */
    /* { */
    /*     .fbuffer = fbuffer, .plan = plan_f, .plan2 = plan_fi, .L = L, .K = K, .W2 = W2, */
    /*     .Wo = Wo, .chirpF = chirpF, .Lfft = Lfft */
    /* }; */

    LTFAT_NAME(chzt_plan) p = (LTFAT_NAME(chzt_plan)) ltfat_malloc(sizeof * p);
    p->fbuffer = fbuffer; p->plan = plan_f; p->plan2 = plan_fi; p->L = L;
    p->K = K; p->W2 = W2; p->Wo = Wo; p->chirpF = chirpF; p->Lfft = Lfft;

    /* memcpy(p, &p_struct, sizeof * p); */

    return  p;
}

LTFAT_API
void LTFAT_NAME(chzt_done)(LTFAT_NAME(chzt_plan) p)
{
    LTFAT_SAFEFREEALL(p->fbuffer, p->W2, p->Wo, p->chirpF);
    /* LTFAT_FFTW(destroy_plan)(p->plan); */
    /* LTFAT_FFTW(destroy_plan)(p->plan2); */
    LTFAT_NAME_REAL(fft_done)(&p->plan);
    LTFAT_NAME_REAL(ifft_done)(&p->plan2);
    ltfat_free(p);
}


LTFAT_API void
LTFAT_NAME(chzt_fac)(const LTFAT_TYPE* fPtr, ltfat_int L,
                     ltfat_int W, ltfat_int K, const LTFAT_REAL deltao,
                     const LTFAT_REAL o, LTFAT_COMPLEX* cPtr)
{
    LTFAT_NAME(chzt_plan) p = LTFAT_NAME(chzt_fac_init)(K, L, deltao, o,
                              FFTW_ESTIMATE, CZT_NEXTFASTFFT);

    LTFAT_NAME(chzt_fac_execute)(p, fPtr, W, cPtr);

    LTFAT_NAME(chzt_done)(p);
}

LTFAT_API void
LTFAT_NAME(chzt_fac_execute)(LTFAT_NAME(chzt_plan) p, const LTFAT_TYPE* fPtr,
                             ltfat_int W, LTFAT_COMPLEX* cPtr)
{
    ltfat_int L = p->L;
    ltfat_int K = p->K;
    ltfat_int Lfft = p->Lfft;
    LTFAT_COMPLEX* fbuffer = p->fbuffer;
    /* LTFAT_FFTW(plan) plan_f = p->plan; */
    /* LTFAT_FFTW(plan) plan_fi = p->plan2; */
    LTFAT_NAME_REAL(fft_plan)*   plan_f = p->plan;
    LTFAT_NAME_REAL(ifft_plan)* plan_fi = p->plan2;
    LTFAT_COMPLEX* W2 = p->W2;
    LTFAT_COMPLEX* Wo = p->Wo;
    LTFAT_COMPLEX* chirpF = p->chirpF;

    LTFAT_COMPLEX* fBufTmp;
    ltfat_int q = (ltfat_int) ceil(((double)L) / ((double)K));

    ltfat_int lastK = (L / q);

    for (ltfat_int w = 0; w < W; w++)
    {
        // *********************************
        // 1) Read and reorganize input data
        // *********************************
        memset(fbuffer, 0, q * Lfft * sizeof * fbuffer);
        LTFAT_TYPE* fPtrTmp = ((LTFAT_TYPE*)fPtr) + w * L;

        for (ltfat_int k = 0; k < lastK; k++)
        {
            LTFAT_TYPE* fTmp = fPtrTmp + k * q;
            fBufTmp = fbuffer + k;
            for (ltfat_int jj = 0; jj < q; jj++)
            {
                *fBufTmp = (LTFAT_COMPLEX) fTmp[jj];
                fBufTmp += Lfft;
            }
        }

        LTFAT_TYPE* fTmp = fPtrTmp + lastK * q;
        fBufTmp = fbuffer + lastK;
        for (ltfat_int jj = 0; jj < L - lastK * q; jj++)
        {
            *fBufTmp = (LTFAT_COMPLEX) fTmp[jj];
            fBufTmp += Lfft;
        }

        // *********************************
        // 2) Premultiply
        // *********************************

        fBufTmp = fbuffer;
        for (ltfat_int jj = 0; jj < q; jj++)
        {
            for (ltfat_int k = 0; k < K; k++)
            {
                fBufTmp[k] *= W2[k];
            }
            fBufTmp += Lfft;
        }

        // *********************************
        // 3) q ffts of length Lfft
        // *********************************
        /* LTFAT_FFTW(execute)(plan_f); */
        LTFAT_NAME_REAL(fft_execute)(plan_f);

        // *********************************
        // 4) Filter
        // *********************************
        fBufTmp = fbuffer;
        // Frequency domain filtering
        for (ltfat_int jj = 0; jj < q; jj++)
        {
            for (ltfat_int ii = 0; ii < Lfft; ii++)
            {
                fBufTmp[ii] *= chirpF[ii];
            }
            fBufTmp += Lfft;
        }

        // *********************************
        // 5) q iffts of length Lfft
        // *********************************
        /* LTFAT_FFTW(execute)(plan_fi); */
        LTFAT_NAME_REAL(ifft_execute)(plan_fi);

        // *********************************
        // 6) Postmultiply
        // *********************************
        fBufTmp = fbuffer;
        LTFAT_COMPLEX* Wotmp = Wo;
        for (ltfat_int jj = 0; jj < q; jj++)
        {
            for (ltfat_int k = 0; k < K; k++)
            {
                fBufTmp[k] *= Wotmp[k];
            }
            fBufTmp += Lfft;
            Wotmp += K;
        }

        // *********************************
        // 7) Sum cols
        // *********************************
        LTFAT_COMPLEX* cPtrTmp = cPtr + w * K;
        for (ltfat_int k = 0; k < K; k++)
        {
            fBufTmp = fbuffer + k;
            cPtrTmp[k] = (LTFAT_COMPLEX) 0.0;
            for (ltfat_int jj = 0; jj < q; jj++)
            {
                cPtrTmp[k] += *fBufTmp;
                fBufTmp += Lfft;
            }
        }

    }
}

LTFAT_API LTFAT_NAME(chzt_plan)
LTFAT_NAME(chzt_fac_init)(ltfat_int K, ltfat_int L,
                          const LTFAT_REAL deltao, const LTFAT_REAL o,
                          const unsigned fftw_flags, czt_ffthint hint)
{

    ltfat_int Lfft = 2 * K - 1;
    if (hint == CZT_NEXTPOW2)
        Lfft = ltfat_nextpow2(Lfft);
    else
        Lfft = ltfat_nextfastfft(Lfft);

    ltfat_int q = (ltfat_int) ceil(((double)L) / ((double)K));

    LTFAT_COMPLEX* fbuffer = LTFAT_NAME_COMPLEX(malloc)(q * Lfft);

    /* LTFAT_FFTW(iodim64) dims; */
    /* dims.n = Lfft; dims.is = 1; dims.os = 1; */
    /* LTFAT_FFTW(iodim64) howmany_dims; */
    /* howmany_dims.n = (int)q; howmany_dims.is = Lfft; howmany_dims.os = Lfft; */
    /* LTFAT_FFTW(plan) plan_f =  LTFAT_FFTW(plan_guru64_dft)(1, &dims, 1, */
    /*                            &howmany_dims, */
    /*                            (LTFAT_FFTW(complex)*) fbuffer, */
    /*                            (LTFAT_FFTW(complex)*) fbuffer, */
    /*                            FFTW_FORWARD, fftw_flags); */
    /*  */
    /* LTFAT_FFTW(plan) plan_fi =  LTFAT_FFTW(plan_guru64_dft)(1, &dims, 1, */
    /*                             &howmany_dims, */
    /*                             (LTFAT_FFTW(complex)*) fbuffer, */
    /*                             (LTFAT_FFTW(complex)*) fbuffer, */
    /*                             FFTW_BACKWARD, fftw_flags); */

    LTFAT_NAME_REAL(fft_plan)*   plan_f;
    LTFAT_NAME_REAL(ifft_plan)* plan_fi;
    LTFAT_NAME_REAL(fft_init)( Lfft, q, fbuffer, fbuffer, fftw_flags, &plan_f);
    LTFAT_NAME_REAL(ifft_init)(Lfft, q, fbuffer, fbuffer, fftw_flags, &plan_fi);

    LTFAT_COMPLEX* W2 = LTFAT_NAME_COMPLEX(malloc)(K);
    LTFAT_COMPLEX* chirpF = LTFAT_NAME_COMPLEX(malloc)(Lfft);
    LTFAT_COMPLEX* Wo = LTFAT_NAME_COMPLEX(malloc)(q * K);

    /* LTFAT_FFTW(plan) plan_chirpF =  LTFAT_FFTW(plan_dft_1d)((int)Lfft, */
    /*                                 (LTFAT_FFTW(complex)*) chirpF, */
    /*                                 (LTFAT_FFTW(complex)*) chirpF, */
    /*                                 FFTW_FORWARD, fftw_flags); */

    for (ltfat_int k = 0; k < K; k++)
    {
        W2[k] = exp(- I * (LTFAT_REAL)( q * deltao *  k * k  / 2.0));
    }

    LTFAT_NAME_COMPLEX(conjugate_array)(W2, K, chirpF);
    LTFAT_NAME_COMPLEX(conjugate_array)(W2 + 1, K - 1, chirpF + Lfft - K + 1);
    LTFAT_NAME_COMPLEX(reverse_array)(chirpF + Lfft - K + 1, K - 1,
                                      chirpF + Lfft - K + 1);
    memset(chirpF + K, 0, (Lfft - (2 * K - 1))*sizeof * chirpF);
    /* LTFAT_FFTW(execute)(plan_chirpF); */
    /* LTFAT_FFTW(destroy_plan)(plan_chirpF); */

    LTFAT_NAME_REAL(ifft)( chirpF, Lfft, 1, chirpF);

    LTFAT_REAL oneoverLfft = (LTFAT_REAL) ( 1.0 / Lfft );

    for (ltfat_int jj = 0; jj < q; jj++)
    {
        LTFAT_COMPLEX* Wotmp = Wo + jj * K;
        for (ltfat_int k = 0; k < K; k++)
        {
            Wotmp[k] = exp(- I * (LTFAT_REAL)jj * ((LTFAT_REAL)k * deltao + o)) * W2[k] *
                       oneoverLfft;
        }
    }

    for (ltfat_int k = 0; k < K; k++)
    {
        W2[k] *= exp(- I * (LTFAT_REAL)(k * q) * o);
    }

    /* struct LTFAT_NAME(chzt_plan_struct) p_struct = */
    /* { */
    /*     .fbuffer = fbuffer, .plan = plan_f, .plan2 = plan_fi, .L = L, .K = K, .W2 = W2, */
    /*     .Wo = Wo, .chirpF = chirpF, .Lfft = Lfft */
    /* }; */

    LTFAT_NAME(chzt_plan) p = (LTFAT_NAME(chzt_plan)) ltfat_malloc(sizeof * p);
    p->fbuffer = fbuffer; p->plan = plan_f; p->plan2 = plan_fi;
    p->L = L; p->K = K; p->W2 = W2; p->Wo = Wo; p->chirpF = chirpF;
    p->Lfft = Lfft;
    /* memcpy(p, &p_struct, sizeof * p); */
    return  p;
}
