[R] Fourier descriptors created in a loop

[David Winsemius]

On Jun 6, 2012, at 5:13 AM, aledanda wrote:

> Hi David,
>
> Thank you for your reply.
>
> /Somehow I'm guessing that this will involve load an unnamed package.
> Yep:
>> ?create.fourier.descriptor
> No documentation for ‘create.fourier.descriptor’ in specified packages
> and libraries:
> you could try ‘??create.fourier.descriptor’/
>
> So I indeed forgot to mention in my post that my script starts with
>
> *library('FourierDescriptors')*
>
>
> /> *count <- seq(1, 7, 0.06)
>>
>> for (i in 1:count){
>
> I was also  wondering what would happen when you passed a vector to
> the ":" operator. A warning at the very least. What was the point of
> this outer loop?/
>
> I need the outer loop for changing the amplitude of my shapes at every
> iteration.
> I specified the amplitudes I want in
>
> count <- seq(1, 7, 0.06).
>
> This outer loop actually works (when I correct the  "for (i in  
> 1:count){"
> into  "for (i in count){.")
> It generates in fact all the shapes I want. The problem is with the  
> inner
> loop, it doesn't seem to save any png picture in my directory. The  
> error is:
>
> *Error in switch(units, `in` = res, cm = res/2.54, mm = res/25.4, px  
> = 1) *
> :
>  non-numeric argument to binary operator*
>
> I report my all script here again:
>
> library('FourierDescriptors')
>
> count <- seq(1, 7, 1)
> # Controlled shapes
> for (i in count){
>  for (s in 1:length(count)){
>    png("~/Desktop/EMAS/FD_stimuli/s1_",s,".png")

Have you considered how difficult it might be to extract any  
information from a .png file that was constructed only one pixel wide?


>    plot(create.fourier.descriptor(amplitude = c(0, i)));
>    dev.off()
>  }
> }
>
> Thank you for your help
> Best
>
> Ale

-- 

David Winsemius, MD
West Hartford, CT