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May 17, 2018 fft and isPowerOf2? | ||||
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Hi, this applications throws an error in std.numeric (Line 2826). => assert(isPowerOf2(range.length)); ----------- module std.numeric void fftImplPureReal(Ret, R)(R range, Ret buf) const in { assert(range.length >= 4); assert(isPowerOf2(range.length)); } ----------- The application is rewritten from python (numpy). How can I workaround this issue? Isn't it possible to give an arbitrary length of data to fft like in numpy? import std.numeric; import std.datetime.stopwatch; import std.stdio: writeln; import std.random; import std.array : array; import std.range : generate, takeExactly; void fourierTest(int samplingRate) { auto sw = StopWatch(AutoStart.yes); foreach(n; 0..60 * 24) { sw.stop(); double[] x = generate!(() => uniform01).takeExactly(samplingRate * 60).array; sw.start(); writeln(x); auto y = fft(x); } sw.stop(); writeln("microseconds: ", sw.peek.total!"usecs"); } void main() { fourierTest(50); } Kind regards André |
May 17, 2018 Re: fft and isPowerOf2? | ||||
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Posted in reply to Andre Pany | On Thursday, 17 May 2018 at 12:34:25 UTC, Andre Pany wrote: > this applications throws an error in std.numeric (Line 2826). > => assert(isPowerOf2(range.length)); > Isn't it possible to give an arbitrary length > of data to fft like in numpy? There is a mathematical background which is well explained here: https://math.stackexchange.com/questions/77118/non-power-of-2-ffts#77152 |
May 18, 2018 Re: fft and isPowerOf2? | ||||
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Posted in reply to kdevel | On Thursday, 17 May 2018 at 13:36:39 UTC, kdevel wrote:
> On Thursday, 17 May 2018 at 12:34:25 UTC, Andre Pany wrote:
>> this applications throws an error in std.numeric (Line 2826).
>> => assert(isPowerOf2(range.length));
>
>> Isn't it possible to give an arbitrary length
>> of data to fft like in numpy?
>
> There is a mathematical background which is well explained here:
>
> https://math.stackexchange.com/questions/77118/non-power-of-2-ffts#77152
Thanks a lot for the details link.
Kind regards
André
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