<div dir="ltr">Hi Peter,<div><br></div><div>All our FFTs employ the same standard output formats as used by e.g. FFTW and and MKL, so for the full documentation it's probably easiest to read there.</div><div><br></div><div>Short story: All values are stored as proper real+complex parts (i.e., 2 real values), so depending on input size the output array might be larger. For in-place R2C transforms that usually means padding (but not out-of-place ones).</div><div><br></div><div>Cheers,</div><div><br></div><div>Erik</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sat, Aug 10, 2019 at 10:36 AM Peter Kasson <<a href="mailto:kasson@virginia.edu">kasson@virginia.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi developers,<div> The doxygen docs are a little ambiguous on gmx_fft_2d_real(), and the source doesn't offer much clarification because we're wrapping external libraries. Given a real-to-complex 2D FFT on a grid of size x by y, is the output a complex grid of size x by y also? There are comments about in-place FFT (which I'm not doing) taking a 5*4 real array and writing a 5*2 complex array.</div><div><br></div><div>(The context of this is trying to compute power spectra for an analysis routine.)</div><div><br></div><div>Thanks,</div><div>--Peter<br clear="all"><div><div dir="ltr" class="gmail-m_-5959976848667769378gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><br>----------------------------------------------------------------------<br>Peter Kasson, MD, PhD<br>Associate Professor<br>Departments of Molecular Physiology and Biological Physics<br>and of Biomedical Engineering<br>University of Virginia<br></div></div></div></div></div></div></div></div>
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