To initialize the library, user will need to construct a data struct and pass it to the library.
For plane-based version, the struct is called: NormalFFTinfo . And the
constructor of 'NormalFFTinfo' is defined as:
NormalFFTinfo(CProxy_NormalSlabArray &srcProxy, CProxy_NormalSlabArray &destProxy,
int srcDim[2], int destDim[2], int isSrcArray, complex *dataptr,
int srcPlanesPerSlab=1, int destPlanesPerSlab=1)
Where:
CProxy_NormalSlabArray &srcProxy : proxy for source charm array
CProxy_NormalSlabArray &destProxy : proxy for destination charm array
int srcDim[2] : FFT plane data dimension at source array (*)
int destDim[2] : FFT plane data dimension at destination array ( srcDim[1] must equal to destDim[0].) (*)
int isSrcArray : whether this array is source (1) or destination (0)
complex *dataptr : pointer to FFT data
int srcPlanesPerSlab : number of planes in each slab at source array, default value is 1 (**)
int destPlanesPerSlab : number of planes in each slab at destination array, default value is 1 (**)
* Data layout : The multi-dimensional FFT data are supposed
to be stored in a contiguous one-dimensional array in
row-major order. For example, in source array, data is
srcPlanesPerSlab planes, each plane is srcDim[0] rows of size srcDim[1] numbers. Similar
rules apply to destination side.
** Currently, srcPlanesPerSlab/destPlanesPerSlab has to be
the same across all array elements.
*** Total data size can be calculated by:
srcPlanesPerSlab*srcDim[0]*srcDim[1] at source array, and
destPlanesPerSlab*destDim[0]*destDim[1] at destination array
For pencil-based version, the struct is called: LineFFTinfo.
LineFFTinfo(CProxy_NormalLineArray &xProxy,
CProxy_NormalLineArray &yProxy,
CProxy_NormalLineArray &zProxy,
int size[3], int isSrcArray, complex *dataptr,
int srcPencilsPerSlab=1, int destPencilsPerSlab=1)
where:
CProxy_NormalSlabArray &xProxy : proxy for first charm array
CProxy_NormalSlabArray &yProxy : proxy for second charm array
CProxy_NormalSlabArray &zProxy : proxy for third charm array
int size[3] : FFT plane data dimension (*)
int isSrcArray : whether this array is source (1) or intermediate (2) or destination (0)
complex *dataptr : pointer to FFT data
int srcPencilsPerSlab : number of pencils in each slab at source array, default value is 1
int destPencilsPerSlab : number of pencils in each slab at destination array, default value is 1
*data layout : pencils in the three arrays are of size size[0]/size[1]/size[2]. And if there is more than one
pencil per slab, the other dimension is the dimension for
pencils in the next array.
In both cases, data is deposited by passing in a pointer to the data
field, and the pointer will be stored in 'complex *dataptr' in the
struct. Memory allocation and initializtion of data field needs to be
done by user before pointer is passed in. The library doesn't allocate
any memory for data field. Also note that FFT's done internally in the
library are in-place FFTs, which means that data field will be
overwriten with results.
