FFT字体如何安装

那就是配源字体文件损坏了。

正常在资源管理里复制到fonts目录里会有安装对话框。

倒培盯态，这是我一个字一个则雹字打出来的！！！再者从内容来看，哪来的粘贴？

FFTW3 is a library designed to compute discrete Fourier transforms. As described in the  the official FFTW site , there are various versions available, with different features and different levels of maturity. In this tutorial I deal with the installation of version 3, including the experimental MPI version. However the installation instructions seems to be valid (although not tested) also for the more popular version 2.

Contents

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1 General Remarks

2 Build and Install

2.1 Serial version only

2.2 MPI version

3 Compilation with Shared Libraries

4 Basic Usage

4.1 Serial

4.2 Parallel MPI

4.2.1 Important notes about MPI-FFTW3 memory distribution (do not skip)

General Remarks

As usual we would like to install the libraries in the user space, so we will create a couple of directories for that purpose:

To install FFTW3, download the package from the  FFTW3 download page  and decompress it:

Ubuntu only:  If you want to install FFTW3 (serial version) in your local Ubuntu you can skip this installation section altogether and just run:

sudo apt-get install libfftw3-dev libfftw3-doc

However the MPI version (e.g. for testing) will not be available. If you want to have the MPI version follow the instructions in the other sections.

Build and Install

The configure/make/install procedure works well for installation in wcr.stanford.edu. We have the option of building and using static or shared libraries. If you are going to use shared libraries read last section.

Serial version only

Then configure, make and install:

(1 minute). The following files will be installed in:

The typical compilation options will be

The official tutorial on the usage of FFTW3 (which is different from FFTW 2) is located  here .

MPI version

To install the experimental MPI version of FFTW3, make sure you downloaded fftw-3.3alpha1 (and not fftw-3.2 for example). Also make sure that there is an MPI compiler available:

If it is not available, you can choose one with the command 'mpi-selector-menu' in wcr. I tested this with the 'openmpi_gcc-1.2.2' compiler. If that is not possible then set the variable MPICC, for example: export MPICC=$HOME/usr/bin/mpicc.

Do the same procedure of downloading the file and decompressing it, but add the --enable-mpi flag:

now the library will be installed in your home directory, besides the files mentioned above, you will find also:

The typical command line for compilation will be

Make sure to link *first* to fftw3_mpi and *later* to fftw3. For some MPI platforms (notably openmpi-gcc) setting LD_RUN_PATH does not do the job of storing the library path inside the executables (see note in previous section), it may be necessary to use the following command:

In any case we should always check that the executable is properly linked by doing

and checking that all shared libraries are "found".

The official tutorial for the MPI version of FFTW3 can be found  here .

Compilation with Shared Libraries

In the command line compilation examples above I set the variables LD_RUN_PATH. Using LD_RUN_PATH saves us from having to set path variables before *running* the program, such as LD_LIBRARY_PATH (which is a  bad practice ). When LD_RUN_PATH is set before compilation, the created executable will store the search path of the shared library internally (but will not enforce it). I learned this trick from  http://gcc.gnu.org/faq.html#rpath  and it works well with gcc at least. Setting this variable before compilation can be annoying, but is better than having to set variables *each time we use* the executable. This seems to be the only good option left when using libraries installed in the home directory (does anybody know a better alternative?).

Update on LD_RUN_PATH: It seems that the trick of setting this variable does not work with mpicxx, at least with the openmpi implementation. A more general way to store the path of the libraries in the executable seems to be to use the option '-Wl,-rpath=$HOME/usr/lib' (sic)as described  here .

Another option to avoid this issues all together is to use the -static option when compiling to ensure that the static fftw3 library files are embedded in the executable. 原网页

Important notes about MPI-FFTW3 memory distribution (do not skip)

Although the resulting distribution of the matrix and allocated memory seems to very reasonable in the previous example, this is only because of the simple dimensions and process number used in the example. There are some characteristics of the memory distribution for which the previous example can be misleading, and it is worth noting them:

Only FFTW (via  fftw_mpi_local_size_2d ) knows how to split the data and allocated memory size among processes, so don't try to predict the splitting yourself.

The splitting of the global matrix is only done over rows (first dimension, for N>2-dimensional arrays).

1D FFT's usage is totally different, because the splitting depends on the type of transform to be performed (e.g. in-place, out-of-place).

The splitting of the matrix can be uneven (for example, #columns is not divisible by #processes).

Some processes can be assigned zero columns (for example if there are more processes than columns). Even in this case, the allocated memory in that process can be different from zero! (in general, it is 1*sizeof(complex)).

The logical size of the submatrix (local matrix) can be different from the local allocated memory, i.e. local_n0*N1 <= alloc_local. The outputs of local_size are not redundant. FFTW uses the (small) extra memory as a scratch space.

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