scfftf(3S)
SCFFTF, SCFFTMF, SCFFT2DF, SCFFT3DF, DZFFTF, DZFFTMF, DZFFT2DF, DZFFT3DF - Deallocate memory tacked on to the table array during initialization
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NAME SCFFTF, SCFFTMF, SCFFT2DF, SCFFT3DF, DZFFTF, DZFFTMF, DZFFT2DF, DZFFT3DF - Deallocate memory tacked on to the table array during initialization SYNOPSIS Single precision complex -> Single precision complex Fortran: istatus = SCFFTF (n, table) istatus = SCFFTMF (n, table) istatus = SCFFT2DF (n1, n2, table) istatus = SCFFT3DF (n1, n2, n3, table) C/C++: #include <scsl_fft.h> istatus = scfftf (int n, float *table); istatus = scfftmf (int n, float *table); istatus = scfft2df (int n1, int n2, float *table); istatus = scfft3df (int n1, int n2, int n3, float *table); Double precision complex -> Double precision complex Fortran: istatus = DZFFTF (n, table) istatus = DZFFTMF (n, table) istatus = DZFFT2DF (n1, n2, table) istatus = DZFFT3DF (n1, n2, n3, table) C/C++: #include <scsl_fft.h> istatus = dzfftf (int n, double *table); istatus = dzfftmf (int n, double *table); istatus = dzfft2df (int n1, int n2, double *table); istatus = dzfft3df (int n1, int n2, int n3, double *table); IMPLEMENTATION These routines are part of the SCSL Scientific Library and can be loaded using either the -lscs or the -lscs_mp option. The -lscs_mp option directs the linker to use the multi-processor version of the library. When linking to SCSL with -lscs or -lscs_mp, the default integer size is 4 bytes (32 bits). Another version of SCSL is available in which integers are 8 bytes (64 bits). This version allows the user access to larger memory sizes and helps when porting legacy Cray codes. It can be loaded by using the -lscs_i8 option or the -lscs_i8_mp option. A program may use only one of the two versions; 4-byte integer and 8-byte integer library calls cannot be mixed. The C and C++ prototypes shown above are appropriate for the 4-byte integer version of SCSL. When using the 8-byte integer version, the variables of type int become long long and the <scsl_fft_i8.h> header file should be included. DESCRIPTION These routines deallocate memory added on to the table array during initialization if the first element of the isys array was set to 0 in the call to SCFFT(3S), SCFFTM(3S), SCFFT2D(3S), SCFFT3D(3S), DZFFT(3S), DZFFTM(3S), DZFFT2D(3S) or DZFFT3D(3S). If the appropriate one of these deallocation routines is not used, that memory will leak, and repeated initializations using the same table array can exhaust memory. If the first element of the isys array was set to 1 in the call to SCCFFT(3S), etc. (and this is the recommended value), there is no potential memory leak and these routines do not need to be called. If they are called, they will simply return 0. See the NOTES section of this man page for information about the interpretation of the data types described in the following arguments. These routines have the following arguments: istatus Integer (result status). (output) 0 indicates the memory was successfully freed. Non-zero indicates that the memory was not freed because the transform size did not match the supplied table array. n Integer. (input) Size of the one dimensional transform (the number of values in the input array used to initialize table). n >= 0. n1 Integer. (input) Transform size in the first dimension. n2 Integer. (input) Transform size in the second dimension. n3 Integer. (input) Transform size in the third dimension. table Array of the following dimensions. (input) SCFFTF: Single precision array of dimension (n + NFR). DZFFTF: Double precision array of dimension (n + NFR). SCFFTMF: Single precision array of dimension (n + NFR). DZFFTMF: Double precision array of dimension (n + NFR). SCFFT2DF: Single precision array of dimension (n1 + NFR) + (2*n2 + NF). DZFFT2DF: Double precision array of dimension (n1 + NFR) + (2*n2 + NF). SCFFT3DF: Single precision array of dimension (n1 + NFR) + (2*n2 + NF) + (2*n3 + NF). DZFFT3DF: Double precision array of dimension (n1 + NF) + (2*n2 + NF) + (2*n3 + NF). Table of factors and roots of unity initialized by a call to the corresponding routine (SCFFT, SCFFTM, SCFFT2D, SCFFT3D, DZFFT, DZFFTM, DZFFT2D, DZFFT3D). NF = 30 and NFR=15 if table was initialized using isys(0)=0. NF=NFR=256 if table was initialized using isys(0)=1. NOTES The following data types are described in this documentation: Term Used Data type Fortran: Array dimensioned 0..n-1 X(0:n-1) Array of dimensions (m,n) X(m,n) Array of dimensions (m,n,p) X(m,n,p) Integer INTEGER (INTEGER*8 for -lscs_i8[_mp]) Single precision REAL Double precision DOUBLE PRECISION Single precision complex COMPLEX Double precision complex DOUBLE COMPLEX C/C++: Array dimensioned 0..n-1 x[n] Array of dimensions (m,n) x[m*n] or x[n][m] Array of dimensions (m,n,p) x[m*n*p] or x[p][n][m] Integer int (long long for -lscs_i8[_mp]) Single precision float Double precision double Single precision complex scsl_complex Double precision complex scsl_zomplex C++ STL: Array dimensioned 0..n-1 x[n] Array of dimensions (m,n) x[m*n] or x[n][m] Array of dimensions (m,n,p) x[m*n*p] or x[p][n][m] Integer int (long long for -lscs_i8[_mp]) Single precision float Double precision double Single precision complex complex<float> Double precision complex complex<double> EXAMPLES Initialize the complex array table in preparation for doing an FFT of size 1024. Take the FFT of x and store the results in y. Deallocate extra memory tagged on to the table array. Fortran: !This example uses isys(0) = 0. The recommended value ! for current versions of SCSL is isys(0) = 1 which, ! if used, will eliminate the need to call SCFFTF. ! REAL X(0:1023) COMPLEX Y(0:1024) REAL TABLE(1024 + 15) ! +15 too small for isys(0) = 1 REAL WORK(1024) INTEGER ISYS(0:0) INTEGER ISTATUS, CCFFTF ISYS(0) = 0 CALL SCFFT(0, 1024, 0.0, DUMMY, DUMMY, TABLE, DUMMY, 0) CALL SCFFT(1, 1024, 1.0, X, Y, TABLE, WORK, 0) ISTATUS = SCFFTF(1024, TABLE) C/C++: /* This example uses isys[0] = 0. The recommended value * for current versions of SCSL is isys[0] = 1 which, * if used, will eliminate the need to call scfftf(). */ #include <scsl_fft.h> float x[1024]; scsl_complex y[1025]; float table[1024 + 15]; /* +15 too small for isys[0] = 1 */ float work[1024]; int isys[1]; int istatus; isys[0] = 0; scfft(0, 1024, 0.0f, NULL, NULL, table, NULL, isys); scfft(1, 1024, 1.0f, X, Y, table, work, isys); istatus = scfftf(1024, table); C++ STL: // This example uses isys[0] = 0. The recommended value // for current versions of SCSL is isys[0] = 1 which, // if used, will eliminate the need to call scfftf(). // #include <complex.h> #include <scsl_fft.h> float x[1024]; complex<float> y[1025]; float table[1024 + 15]; /* +15 too small for isys[0] = 1 */ float work[2*1024]; int isys[1]; int istatus; isys[0] = 0; scfft(0, 1024, 0.0f, NULL, NULL, table, NULL, isys); scfft(1, 1024, 1.0f, X, Y, table, work, isys); istatus = scfftf(1024, table); SEE ALSO INTRO_FFT(3S), INTRO_SCSL(3S)