kml_fft(f)_plan_guru64_split_dft_c2r
建立多组数据序列n维C2R变换的plan。其中，单个FFT的数据序列不需要是连续的，可以以跨步的形式提供。split类接口的输入和输出分别存储在实部和虚部数组中。与kml_fft(f)_plan_guru_split_dft_r2c不同的是，kml_fft(f)_plan_guru64_split_dft_r2c允许部分参数是64位的整型。
接口定义
C interface:
kml_fft_plan kml_fft_plan_guru_split_dft_c2r(int rank, const kml_fft_iodim64 *dims, int howmany_rank, const kml_fft_iodim64 *howmany_dims, double *ri, double *ii, double *out, unsigned flags);
kml_fftf_plan kml_fftf_plan_guru_split_dft_c2r(int rank, const kml_fftf_iodim64 *dims, int howmany_rank, const kml_fftf_iodim64 *howmany_dims, float *ri, float *ii, float *out, unsigned flags);
Fortran interface:
RES = KML_FFT_PLAN_GURU64_SPLIT_DFT_C2R(RANK, DIMS, HOWMANY_RANK, HOWMANY_DIMS, RI, II, OUT, FLAGS);
RES = KML_FFTF_PLAN_GURU64_SPLIT_DFT_C2R(RANK, DIMS, HOWMANY_RANK, HOWMANY_DIMS, RI, II, OUT, FLAGS);
返回值
函数返回一个kml_fft(f)_plan类型的结构体指针。将该对象作为参数传入kml_fft(f)_execute函数中使用，将对当前提供的输入ri，ii和输出out执行FFT变换；另外，也可以通过将该对象作为参数传入kml_fft(f)_execute_split_dft_c2r函数中以对新的输入ri，ii和输出out执行FFT变换。
如果函数返回非空指针，则表示plan执行成功，否则表示执行失败。
参数
参数名 |
数据类型 |
描述 |
输入/输出 |
|---|---|---|---|
rank |
int |
单个FFT序列的维度。 约束：1 <= rank <= 3。 |
输入 |
dims |
|
dims是大小为rank的结构体数组，dims[i]包含以下成员：
约束：dims[i].n >= 1, for i in 0 to rank - 1。 |
输入 |
howmany_rank |
int |
多个rank维FFT之间的内存排布用howmany_rank维的howmany_dims数组来描述，howmany_rank表示每个要计算的rank维FFT变换的起始地址的内存访问模式所需的维数。 约束：0 <= howmany_rank <= 3。 |
输入 |
howmany_dims |
|
howmany_dims是大小为howmany_rank的结构体数组，howmany_dims[i]包含以下成员：
|
输入 |
ri |
|
输入待变换数据的实部。 |
输入 |
ii |
|
输入待变换数据的虚部。 |
输入 |
out |
|
输出快速傅里叶变换后的数据。 |
输出 |
flags |
unsigned int |
planning选项，未使用。 |
输入 |
依赖
C: "kfft.h"
Fortran: "kfft.f03"
示例
C interface:
int rank = 2;
kml_fft_iodim64 *dims;
dims = (kml_fft_iodim64*)kml_fft_malloc(sizeof(kml_fft_iodim64) * rank);
dims[0].n = 2;
dims[0].is = 2;
dims[0].os = 3;
dims[1].n = 3;
dims[1].is = 1;
dims[1].os = 1;
int howmany_rank = 1;
kml_fft_iodim64 *howmany_dims;
howmany_dims = (kml_fft_iodim64*)kml_fft_malloc(sizeof(kml_fft_iodim64) * howmany_rank);
howmany_dims[0].n = 2;
howmany_dims[0].is = 2 * 2;
howmany_dims[0].os = 2 * 3;
double init[8][2] = {{120, 0}, {8, 8}, {0, 0}, {0, 16}, {0, 16}, {-8, 8}, {-8, 0}, {-8, 8}};
double *ri;
ri = (double*)kml_fft_malloc(sizeof(double) * 8);
double *ii;
ii = (double*)kml_fft_malloc(sizeof(double) * 8);
for (int i = 0; i < 8; i++) {
ri[i] = init[i][0];
ii[i] = init[i][1];
}
double *out;
out = (double*)kml_fft_malloc(sizeof(double) * 12);
kml_fft_plan plan;
plan = kml_fft_plan_guru64_split_dft_c2r(rank, dims, howmany_rank, howmany_dims, ri, ii, out, KML_FFT_ESTIMATE);
kml_fft_execute_split_dft_c2r(plan, ri, ii, out);
kml_fft_destroy_plan(plan);
kml_fft_free(howmany_dims);
kml_fft_free(dims);
kml_fft_free(ri);
kml_fft_free(ii);
kml_fft_free(out);
/*
* out = {1.360000e+02, 7.043078e+01, 1.535692e+02, 1.360000e+02,
* 1.258564e+02, 9.814359e+01, -4.000000e+01, -1.971281e+01,
* 3.571281e+01, 8.000000e+00, 8.000000e+00, 8.000000e+00}
*/
Fortran interface:
INTEGER(C_INT) :: RANK = 2
INTEGER(C_INT) :: HOWMANY_RANK = 1
REAL(C_DOUBLE), DIMENSION(8, 2) :: INIT
TYPE(KML_FFT_IODIM64), POINTER :: DIMS(:), HOWMANY_DIMS(:)
REAL(8), POINTER :: RI(:), II(:), OUT(:)
TYPE(C_PTR) :: PRI,PII, POUT, PDIMS, PHOWMANY_DIMS
INTEGER(C_SIZE_T) :: CSIZE, RSIZE
CSIZE = 8 * 8
RSIZE = 8 * 12
PRI = KML_FFT_MALLOC(CSIZE)
PII = KML_FFT_MALLOC(CSIZE)
POUT = KML_FFT_MALLOC(RSIZE)
CALL C_F_POINTER(PRI, IN, SHAPE=[8])
CALL C_F_POINTER(PII, IN, SHAPE=[8])
CALL C_F_POINTER(POUT, OUT, SHAPE=[12])
CSIZE = 24 * 2
RSIZE = 24 * 1
PIODIMS = KML_FFT_MALLOC(CSIZE)
PHOWMANY_IODIMS = KML_FFT_MALLOC(RSIZE)
CALL C_F_POINTER(PIODIMS, DIMS, SHAPE=[2])
CALL C_F_POINTER(PHOWMANY_DIMS, HOWMANY_DIMS, SHAPE=[1])
DIMS(0)%N = 2
DIMS(0)%IS = 2
DIMS(0)%OS = 3
DIMS(1)%N = 3
DIMS(1)%IS = 1
DIMS(1)%OS = 1
HOWMANY_DIMS(0)%N = 2
HOWMANY_DIMS(0)%IS = 2 * 2
HOWMANY_DIMS(0)%OS = 2 * 3
DATA INIT/120, 8, 0, 0, 0, -8, -8, -8, 0, 8, 0, 16, 16, 8, 0, 8/
INTEGER :: I
DO WHILE(I <= 8)
RI(I) = INIT(I, 0)
II(I) = INIT(I, 1)
END DO
TYPE(C_PTR) :: PLAN
PLAN = KML_FFT_PLAN_GURU64_SPLIT_DFT_C2R(RANK, DIMS, HOWMANY_RANK, HOWMANY_DIMS, RI, II, OUT, KML_FFT_ESTIMATE)
CALL KML_FFT_EXECUTE_SPLIT_DFT_C2R(PLAN, RI, II, OUT);
CALL KML_FFT_DESTROY_PLAN(PLAN)
CALL KML_FFT_FREE(PHOWMANY_DIMS)
CALL KML_FFT_FREE(PDIMS)
CALL KML_FFT_FREE(PRI)
CALL KML_FFT_FREE(PII)
CALL KML_FFT_FREE(POUT)
!
! OUT = /1.360000E+02, 7.043078E+01, 1.535692E+02, 1.360000E+02,
! 1.258564E+02, 9.814359E+01, -4.000000E+01, -1.971281E+01,
! 3.571281E+01, 8.000000E+00, 8.000000E+00, 8.000000E+00/
!