//

// File:       fft_internal.h

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////////////////////////////////////////////////////////////////////////////////////////////////////

#ifndef __CLFFT_INTERNAL_H

#define __CLFFT_INTERNAL_H

#include "clFFT.h"

#include <iostream>

#include <string>

#include <sstream>

using namespace std;

typedef enum kernel_dir_t

{

    cl_fft_kernel_x,

    cl_fft_kernel_y,

    cl_fft_kernel_z

}cl_fft_kernel_dir;

typedef struct kernel_info_t

{

    cl_kernel kernel;

    char *kernel_name;

    unsigned lmem_size;

    unsigned num_workgroups;

    unsigned num_xforms_per_workgroup;

    unsigned num_workitems_per_workgroup;

    cl_fft_kernel_dir dir;

    int in_place_possible;

    kernel_info_t *next;

}cl_fft_kernel_info;

typedef struct 

{

    // context in which fft resources are created and kernels are executed

    cl_context              context;

    // size of signal

    clFFT_Dim3              n;

    // dimension of transform ... must be either 1D, 2D or 3D

    clFFT_Dimension         dim;

    // data format ... must be either interleaved or plannar

    clFFT_DataFormat        format;

    // string containing kernel source. Generated at runtime based on

    // n, dim, format and other parameters

    string                  *kernel_string;

    // CL program containing source and kernel this particular 

    // n, dim, data format

    cl_program              program;

    // linked list of kernels which needs to be executed for this fft

    cl_fft_kernel_info      *kernel_info;

    // number of kernels

    int                     num_kernels;

    // twist kernel for virtualizing fft of very large sizes that do not

    // fit in GPU global memory

    cl_kernel               twist_kernel;

    // flag indicating if temporary intermediate buffer is needed or not.

    // this depends on fft kernels being executed and if transform is 

    // in-place or out-of-place. e.g. Local memory fft (say 1D 1024 ... 

    // one that does not require global transpose do not need temporary buffer)

    // 2D 1024x1024 out-of-place fft however do require intermediate buffer.

    // If temp buffer is needed, its allocation is lazy i.e. its not allocated

    // until its needed

    cl_int                  temp_buffer_needed;

    // Batch size is runtime parameter and size of temporary buffer (if needed)

    // depends on batch size. Allocation of temporary buffer is lazy i.e. its

    // only created when needed. Once its created at first call of clFFT_Executexxx

    // it is not allocated next time if next time clFFT_Executexxx is called with 

    // batch size different than the first call. last_batch_size caches the last

    // batch size with which this plan is used so that we dont keep allocating/deallocating

    // temp buffer if same batch size is used again and again.

    unsigned                  last_batch_size;

    // temporary buffer for interleaved plan

    cl_mem                  tempmemobj;

    // temporary buffer for planner plan. Only one of tempmemobj or 

    // (tempmemobj_real, tempmemobj_imag) pair is valid (allocated) depending 

    // data format of plan (plannar or interleaved)

    cl_mem                  tempmemobj_real, tempmemobj_imag;

    // Maximum size of signal for which local memory transposed based

    // fft is sufficient i.e. no global mem transpose (communication)

    // is needed

    unsigned                    max_localmem_fft_size;

    // Maximum work items per work group allowed. This, along with max_radix below controls 

    // maximum local memory being used by fft kernels of this plan. Set to 256 by default

    unsigned                  max_work_item_per_workgroup;

    // Maximum base radix for local memory fft ... this controls the maximum register 

    // space used by work items. Currently defaults to 16

    unsigned                  max_radix;

    // Device depended parameter that tells how many work-items need to be read consecutive

    // values to make sure global memory access by work-items of a work-group result in 

    // coalesced memory access to utilize full bandwidth e.g. on NVidia tesla, this is 16

    unsigned                  min_mem_coalesce_width;

    // Number of local memory banks. This is used to geneate kernel with local memory 

    // transposes with appropriate padding to avoid bank conflicts to local memory

    // e.g. on NVidia it is 16.

    unsigned                  num_local_mem_banks;

}cl_fft_plan;

void FFT1D(cl_fft_plan *plan, cl_fft_kernel_dir dir);

#endif