fftw

Edit: I resolved this issue, the solution is below. I am building a code in a shared computing cluster dedicated for scientific computing, thus I can only control files in my home folder. Although I am using fftw as an example, I would like to understand the specific reason, why my attempt to setup LD_LIBRARY_PATH does not work. I build the fftw and fftw_mpi libraries in my home folder like this ./configure --prefix=$HOME/install/fftw --enable-mpi --enable-shared make install It builds fine, but in install/fftw/lib, I find that the freshly built libfftw3_mpi.so links to wrong version of fftw

Blow is a main file PROGRAM SPHEROID USE nrtype USE SUB_INFO INCLUDE "/usr/local/include/fftw3.f" INTEGER(I8B) :: plan_forward, plan_backward INTEGER(I4B) :: i, t, int_N REAL(DP) :: cth_i, sth_i, real_i, perturbation REAL(DP) :: PolarEffect, dummy, x1, x2, x3 REAL(DP), DIMENSION(4096) :: dummy1, dummy2, gam, th, ph REAL(DP), DIMENSION(4096) :: k1, k2, k3, k4, l1, l2, l3, l4, f_in COMPLEX(DPC), DIMENSION(2049) :: output1, output2, f_out CHARACTER(1024) :: baseOutputFilename CHARACTER(1024) :: outputFile, format_string !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! int_N

I've asked a similar question,which was answered but when I try to do it my way I get "strange" values. I want to get the PSD of a sin wave use the half complex transformation like : #include <stdio.h> #include <fftw3.h> #include <complex.h> #include <stdlib.h> #include <math.h> #define PI 3.141592653589793 int main (){ double* inputValues; double* outputValues; double realVal; double imagVal; double powVal=0.0; double absVal; double timer; fftw_plan plan; double timeIntervall= 1.0; // 1sec int numberOfSamples =512; double timeSteps = timeIntervall/numberOfSamples; float frequency=10.0; float

I'm writing a simple code for complex to complex DFT in c with fftw3 library. i have written a file with input array double data so I can compare with matlab fft function. I try to execute the reverse transform from transform array but results and first input array are different. this is my results: FFTW3 TRANSFORM WELCOME <<<<< enter the number (integer) N of samples (Bit: 64) (preferably power of 2):8 SAMPLE INPUT in[0][0] = -216448918.015237 in[0][1] = 0.000000 in[1][0] = 948904790.062151 in[1][1] = 0.000000 in[2][0] = 826811206.185300 in[2][1] = 0.000000 in[3][0] = 1868763250.342451 in[3]

I wrote two identical programs in Linux and Windows using the fftw libraries ( fftw3.a , fftw3.lib ), and compute the duration of the fftwf_execute(m_wfpFFTplan) statement (16-fft). For 10000 runs: On Linux: average time is 0.9 On Windows: average time is 0.12 I am confused as to why this is nine times faster on Windows than on Linux. Processor: Intel(R) Core(TM) i7 CPU 870 @ 2.93GHz Each OS (Windows XP 32 bit and Linux OpenSUSE 11.4 32 bit) are installed on same machines. I downloaded the fftw.lib (for Windows) from internet and don't know that configurations. Once I build FFTW with this

I wrote a simple test program, where I was doing Complex to Complex FT's and I just generated some data 1..50 and stuck it in for the real and imaginary part for each index of the array. When I do an operation like this IFFT(FFT(A)) = A to test them out, I am getting different results for each library. FFTW, I have to divide the output by len(A) to get back the original A However, doing this forward then reverse FFT with CUFFT, it looks like I have to divide by (sqrt(2)*50) to get back to the original data. Where is this extra square root factor coming from? according to the CUFFT