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fortran

Fortran representation of symbolic expression

Syntax

fortran(f)
fortran(f,Name,Value)

Description

fortran(f) returns Fortran code for the symbolic expression f.

example

fortran(f,Name,Value) uses additional options specified by one or more Name,Value pair arguments.

Examples

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Generate Fortran code from the symbolic expression log(1+x).

syms x
f = log(1+x);
fortran(f)
ans =
    '      t0 = log(x+1.0D0)'

Generate Fortran code for the 3-by-3 Hilbert matrix.

H = sym(hilb(3));
fortran(H)
ans =
    '      H(1,1) = 1.0D0
           H(1,2) = 1.0D0/2.0D0
           H(1,3) = 1.0D0/3.0D0
           H(2,1) = 1.0D0/2.0D0
           H(2,2) = 1.0D0/3.0D0
           H(2,3) = 1.0D0/4.0D0
           H(3,1) = 1.0D0/3.0D0
           H(3,2) = 1.0D0/4.0D0
           H(3,3) = 1.0D0/5.0D0'

Write generated Fortran code to a file by specifying the File option. When writing to a file, fortran optimizes the code using intermediate variables named t0, t1, .… Include comments in the file by using the Comments option.

syms x
f = diff(tan(x));
fortran(f,'File','fortrantest')
      t2 = tan(x)
      t0 = t2**2+1.0D0

Include the comment Version: 1.1. Comment lines must be shorter than 71 characters to conform with Fortran 77.

fortran(f,'File','fortrantest','Comments','Version: 1.1')
*Version: 1.1
      t2 = tan(x)
      t0 = t2**2+1.0D0

Input Arguments

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Symbolic input, specified as a symbolic expression.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside single quotes (' '). You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: fortran(x^2,'File','fortrancode','Comments','V1.2')

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File to write to, specified as a character vector or string. When writing to a file, fortran optimizes the code using intermediate variables named t0, t1, ....

Comments to include in the file header, specified as a character vector, cell array of character vectors, or string vector. Comment lines must be shorter than 71 characters to conform with Fortran 77.

Tips

  • MATLAB® is left-associative while Fortran is right-associative. If ambiguity exists in an expression, the fortran function must follow MATLAB to create an equivalent representation. For example, fortran represents a^b^c in MATLAB as (a**b)**c in Fortran.

Introduced before R2006a

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