/*******************************************************************************
* Copyright 2011-2018 Intel Corporation.
*
* This software and the related documents are Intel copyrighted materials, and
* your use of them is governed by the express license under which they were
* provided to you (License). Unless the License provides otherwise, you may not
* use, modify, copy, publish, distribute, disclose or transmit this software or
* the related documents without Intel's prior written permission.
*
* This software and the related documents are provided as is, with no express
* or implied warranties, other than those that are expressly stated in the
* License.
*******************************************************************************/
/*
! Content:
! An example of using DFTI_NUMBER_OF_TRANSFORMS configuration parameter.
! The parameter defines how many identical transforms are computed by one call
! of DftiComputeForward or DftiComputeBackward function.
!
! Values:
! A positive integer (default 1)
!
!****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <float.h>
#include "mkl_service.h"
#include "mkl_dfti.h"
static void init(MKL_Complex16 *x, MKL_LONG M,
MKL_LONG N1, MKL_LONG N2, MKL_LONG N3,
MKL_LONG H1, MKL_LONG H2, MKL_LONG H3);
static int verify(MKL_Complex16 *x, MKL_LONG M,
MKL_LONG N1, MKL_LONG N2, MKL_LONG N3,
MKL_LONG H1, MKL_LONG H2, MKL_LONG H3);
/* Define the format to printf MKL_LONG values */
#if !defined(MKL_ILP64)
#define LI "%li"
#else
#define LI "%lli"
#endif
int main(void)
{
/* Sizes of 3D transform */
MKL_LONG N[3] = { 7, 13, 5 };
/* Number of transforms */
MKL_LONG M = 4;
/* Arbitrary harmonic used to verify FFT */
MKL_LONG H[3] = { 1, -1, -2 };
/* Execution status */
MKL_LONG status = 0;
/* Pointer to input/output data */
MKL_Complex16 *x = 0;
DFTI_DESCRIPTOR_HANDLE hand = 0;
/* Distance between first elements for multiple transforms */
MKL_LONG dist;
char version[DFTI_VERSION_LENGTH];
DftiGetValue(0, DFTI_VERSION, version);
printf("%s\n", version);
printf("Example config_number_of_transforms\n");
printf("Multiple in-place 3D FFT\n");
printf("Configuration parameters:\n");
printf(" DFTI_PRECISION = DFTI_DOUBLE\n");
printf(" DFTI_FORWARD_DOMAIN = DFTI_COMPLEX\n");
printf(" DFTI_DIMENSION = 3\n");
printf(" DFTI_LENGTHS = { "LI", "LI", "LI" }\n", N[0], N[1], N[2]);
printf(" DFTI_NUMBER_OF_TRANSFORMS = "LI"\n", M);
printf("Create DFTI descriptor for double-precision 3D transform\n");
status = DftiCreateDescriptor(&hand, DFTI_DOUBLE, DFTI_COMPLEX, 3, N);
if (status != DFTI_NO_ERROR) goto failed;
printf("Set configuration: DFTI_NUMBER_OF_TRANSFORMS\n");
status = DftiSetValue(hand, DFTI_NUMBER_OF_TRANSFORMS, M);
if (status != DFTI_NO_ERROR) goto failed;
dist = N[0]*N[1]*N[2];
printf("Set configuration: DFTI_INPUT_DISTANCE = "LI"\n",dist);
status = DftiSetValue(hand, DFTI_INPUT_DISTANCE, dist);
if (status != DFTI_NO_ERROR) goto failed;
/*
* Output distance is ignored for in-place complex transforms.
*
* status = DftiSetValue(hand, DFTI_INPUT_DISTANCE, dist);
* if (status != DFTI_NO_ERROR) goto failed;
*/
printf("Commit descriptor\n");
status = DftiCommitDescriptor(hand);
if (status != DFTI_NO_ERROR) goto failed;
/* Allocate input array */
x = (MKL_Complex16*)mkl_malloc(M * N[0]*N[1]*N[2] * sizeof(MKL_Complex16),
64);
if (x == NULL) goto failed;
printf("Initialize input for forward transform\n");
init(x, M, N[0], N[1], N[2], H[0], H[1], H[2]);
printf("Compute forward transform\n");
status = DftiComputeForward(hand, x);
if (status != DFTI_NO_ERROR) goto failed;
printf("Verify the result\n");
status = verify(x, M, N[0], N[1], N[2], H[0], H[1], H[2]);
if (status != 0) goto failed;
printf("Initialize input for backward transform\n");
init(x, M, N[0], N[1], N[2], -H[0], -H[1], -H[2]);
printf("Compute backward transform\n");
status = DftiComputeBackward(hand, x);
if (status != DFTI_NO_ERROR) goto failed;
printf("Verify the result\n");
status = verify(x, M, N[0], N[1], N[2], H[0], H[1], H[2]);
if (status != 0) goto failed;
cleanup:
printf("Free DFTI descriptor\n");
DftiFreeDescriptor(&hand);
printf("Free data array\n");
mkl_free(x);
printf("TEST %s\n", (status == 0) ? "PASSED" : "FAILED");
return status;
failed:
printf(" ERROR, status = "LI"\n", status);
status = 1;
goto cleanup;
}
/* Compute (K*L)%M accurately */
static double moda(MKL_LONG K, MKL_LONG L, MKL_LONG M)
{
return (double)(((long long)K * L) % M);
}
/* Initialize array with harmonic {H1, H2, H3} */
static void init(MKL_Complex16 *x, MKL_LONG M,
MKL_LONG N1, MKL_LONG N2, MKL_LONG N3,
MKL_LONG H1, MKL_LONG H2, MKL_LONG H3)
{
double TWOPI = 6.2831853071795864769, phase;
MKL_LONG m, n1, n2, n3, index;
/* Generalized strides for row-major addressing of x */
MKL_LONG SM = N1*N2*N3, S1 = N2*N3, S2 = N3, S3 = 1;
for (m = 0; m < M; m++)
{
for (n1 = 0; n1 < N1; n1++)
{
for (n2 = 0; n2 < N2; n2++)
{
for (n3 = 0; n3 < N3; n3++)
{
phase = moda(n1,H1,N1) / N1;
phase += moda(n2,H2,N2) / N2;
phase += moda(n3,H3,N3) / N3;
index = m*SM + n1*S1 + n2*S2 + n3*S3;
x[index].real = cos( TWOPI * phase ) / (N1*N2*N3);
x[index].imag = sin( TWOPI * phase ) / (N1*N2*N3);
}
}
}
}
}
/* Verify that x(n1,n2,n3,m) are unit peaks at H1,H2,H3 */
static int verify(MKL_Complex16 *x, MKL_LONG M,
MKL_LONG N1, MKL_LONG N2, MKL_LONG N3,
MKL_LONG H1, MKL_LONG H2, MKL_LONG H3)
{
double err, errthr, maxerr;
MKL_LONG m, n1, n2, n3, index;
/* Generalized strides for row-major addressing of x */
MKL_LONG SM = N1*N2*N3, S1 = N2*N3, S2 = N3, S3 = 1;
/*
* Note, this simple error bound doesn't take into account error of
* input data
*/
errthr = 5.0 * log( (double)N1*N2*N3 ) / log(2.0) * DBL_EPSILON;
printf(" Verify the result, errthr = %.3lg\n", errthr);
maxerr = 0;
for (m = 0; m < M; m++)
{
for (n1 = 0; n1 < N1; n1++)
{
for (n2 = 0; n2 < N2; n2++)
{
for (n3 = 0; n3 < N3; n3++)
{
double re_exp = 0.0, im_exp = 0.0, re_got, im_got;
if ((n1-H1)%N1==0 && (n2-H2)%N2==0 && (n3-H3)%N3==0)
{
re_exp = 1;
}
index = m*SM + n1*S1 + n2*S2 + n3*S3;
re_got = x[index].real;
im_got = x[index].imag;
err = fabs(re_got - re_exp) + fabs(im_got - im_exp);
if (err > maxerr) maxerr = err;
if (!(err < errthr))
{
printf(" x["LI"]["LI"]["LI"]["LI"]: ",m,n1,n2,n3);
printf(" expected (%.17lg,%.17lg), ",re_exp,im_exp);
printf(" got (%.17lg,%.17lg), ",re_got,im_got);
printf(" err %.3lg\n", err);
printf(" Verification FAILED\n");
return 1;
}
}
}
}
}
printf(" Verified, maximum error was %.3lg\n", maxerr);
return 0;
}