在Fortran中将复杂矩阵写入文件 [英] Writing a complex matrix to a file in Fortran

问题描述

如何在Fortran中将复杂(n×n)矩阵写入文件? 例如:

How does one write a complex (n×n) matrix in Fortran to a file? For example:

DO I=1,N
       write(14,'(100g15.5)') ( M(i,j), j=1,n )
ENDDO  

在此示例中，将2n×n个元素写入文件，即实数和虚数. 代替两个元素Re(a11)Im(a11)，我如何将其写为一个元素Re(a11)+ iIm(a11)?

In this example one gets 2n×n elements written to the file i.e. the real and imaginary. Instead of two element, Re(a11) Im(a11), How can I write it as one element Re(a11)+iIm(a11)?

推荐答案

使用内在函数REAL和AIMAG编写复数的各个实部和虚部:

Use intrinsic functions REAL and AIMAG to write individual real and imaginary components of a complex number:

CHARACTER(LEN=3),DIMENSION(n,n) :: imag_unit = '+i*'

WHERE(AIMAG(M)<0.)imag_unit = '-i*'

DO I=1,N
  write(14,'(100(g15.5,a,g15.5,2x))') ( REAL(M(i,j)),imag_unit(i,j),&
                                        ABS(AIMAG(M(i,j))), j=1,n )
ENDDO 

说明:该代码定义了一个字符串矩阵，当虚部为正时，值为"+ i"；当虚部为负时，值为"-i".因为负虚数部分在格式('-i')中占位，所以我们采用虚数部分的绝对值.相应地编辑格式描述符，以便您用于读取输出文件的程序将能够读取它.

Explanation: This code defines a matrix of character strings that have value '+i' when imaginary part is positive, and '-i' where imaginary part is negative. Because the negative imaginary part is accounted for in the formatting ('-i'), we take absolute value of the imaginary part. Edit the format descriptor accordingly so that the program you use to read the output file will be able to read it.

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