diff options
Diffstat (limited to 'macros/ifft2.sci')
-rw-r--r-- | macros/ifft2.sci | 100 |
1 files changed, 55 insertions, 45 deletions
diff --git a/macros/ifft2.sci b/macros/ifft2.sci index 8ecb1a5..762631d 100644 --- a/macros/ifft2.sci +++ b/macros/ifft2.sci @@ -1,45 +1,55 @@ -function res = ifft2 (A, m, n) -//Calculates the inverse two-dimensional discrete Fourier transform of A using a Fast Fourier Transform algorithm. -//Calling Sequence -//ifft2 (A, m, n) -//ifft2 (A) -//Parameters -//A: input matrix -//m: number of rows of A to be used -//n: number of columns of A to be used -//Description -//This is an Octave function. -//It performs inverse two-dimensional FFT on the matrix A. m and n may be used specify the number of rows and columns of A to use. If either of these is larger than the size of A, A is resized and padded with zeros. -//If A is a multi-dimensional matrix, each two-dimensional sub-matrix of A is treated separately. -//Examples -//x = [1 2 3; 4 5 6; 7 8 9] -//m = 4 -//n = 4 -//ifft2 (A, m, n) -//ans = -// -// 2.81250 + 0.00000i -0.37500 + 0.93750i 0.93750 + 0.00000i -0.37500 - 0.93750i -// -1.12500 + 0.93750i -0.31250 - 0.50000i -0.37500 + 0.31250i 0.31250 + 0.25000i -// 0.93750 + 0.00000i -0.12500 + 0.31250i 0.31250 + 0.00000i -0.12500 - 0.31250i -// -1.12500 - 0.93750i 0.31250 - 0.25000i -0.37500 - 0.31250i -0.31250 + 0.50000i - -funcprot(0); -lhs = argn(1) -rhs = argn(2) -if (rhs < 1 | rhs > 3) -error("Wrong number of input arguments.") -end - -select(rhs) - - case 1 then - res = callOctave("ifft2", A) - - case 2 then - error("Wrong number of input arguments.") - - case 3 then - res = callOctave("ifft2", A, m, n) - - end -endfunction +Author: Abinash Singh <abinashsinghlalotra@gmail.com>
+*/
+/*Description
+ Calculates the inverse two-dimensional discrete Fourier transform of A using a Fast Fourier Transform algorithm.
+ It performs inverse two-dimensional FFT on the matrix A. m and n may be used specify the number of rows and columns of A to use. If either of these is larger
+ than the size of A, A is resized and padded with zeros.
+ If A is a multi-dimensional matrix, each two-dimensional sub-matrix of A is treated separately.
+Calling Sequence
+ ifft2 (A)
+ ifft2 (A, m, n)
+Parameters
+ A: input matrix
+ m: number of rows of A to be used
+ n: number of columns of A to be used
+Examples
+ A= [1 2 3; 4 5 6; 7 8 9]
+ m = 4
+ n = 4
+ ifft2 (A, m, n) --functionCall
+ ans =
+ 2.81250 + 0.00000i -0.37500 + 0.93750i 0.93750 + 0.00000i -0.37500 - 0.93750i
+ -1.12500 + 0.93750i -0.31250 - 0.50000i -0.37500 + 0.31250i 0.31250 + 0.25000i
+ 0.93750 + 0.00000i -0.12500 + 0.31250i 0.31250 + 0.00000i -0.12500 - 0.31250i
+ -1.12500 - 0.93750i 0.31250 - 0.25000i -0.37500 - 0.31250i -0.31250 + 0.50000i
+*/
+function res = ifft2(A, m, n)
+ funcprot(0);
+ lhs = argn(1)
+ rhs = argn(2)
+ if (rhs < 1 | rhs > 3)
+ error("Wrong number of input arguments.")
+ end
+ size_x=size(A)
+ len=length(size_x)
+ //to figure out size of multidimensional array
+ if len>2 then
+ last_dim=size_x(len)
+ else
+ last_dim=1
+ end
+ select(rhs)
+ case 1 then
+ res=[]
+ for i=1:last_dim //treating each submatrix seperately
+ res(:,:,i)=fft(A(:,:,i),1)
+ end
+ case 2 then
+ error("Wrong number of input arguments.")
+ case 3 then
+ res=[]
+ for i=1:last_dim
+ res(:,:,i)=fft(resize_matrix(A(:,:,i),m,n),1)
+ end
+ end
+endfunction
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