int n_ok(unsigned int rank, unsigned int *n)
{
unsigned int i;
for (i = 0; i < rank; ++i)
if (!check_prime_factors(n[i], 5))
return 0;
return 1;
}
/** Compute the ceiling of len that is also a product of powers of 2, 3, 5.
* Use check_prime_factors to get the smallest integer greater or equal
* than len which is decomposable into powers of 2, 3, 5.
*/
int Ewald_ParticleMesh::ComputeNFFT(double len) {
int mval = (int)len - 1;
for (int i = 0; i < 100; i++) {
mval += 1;
// Sanity check
if (mval < 1) {
mprinterr("Error: Bad box length %g, cannot get NFFT value.\n", len);
return 0;
}
if (check_prime_factors(mval))
return mval;
}
mprinterr("Error: Failed to get good FFT array size for length %g Ang.\n", len);
return 0;
}
