Generate FORTRAN77 code from Mathematica

Question

I need to transform a function from Mathematica to Fortran77. An internal program FortranForm gives some result, but it works incorrectly in Fortran77. The string must start a 7th column and finish at 72th, ArcTan and Log must be transformed to ATAN and DLOG respectively, numbers also must be transformed (e.g. 2. -> 2d0).

I have a function:

 C3 (c - y) + 
 C3 (c + y) + ((1 + nu) (-1 + 2 nu) P (c - y) ArcTan[(-c + y)/
   x])/(π Y) + ((1 + nu) (-1 + 2 nu) P (c + y) ArcTan[(c + y)/
   x])/(π Y) + ((-1 + nu) (1 + nu) P x Log[
   x^2 + (c - y)^2])/(π Y) + ((1 + nu) P (x - nu x) Log[
   x^2 + (c + y)^2])/(π Y)

I'd like to have the following result:

< V = C3*(c - y) + C3*(c + y) + 
 &  ((1D0 + nu)*(-1D0 + 2D0*nu)*P*(c - y)*ATAN((-c + y)/x))/(Pi*E) + 
 &  ((1D0 + nu)*(-1D0 + 2D0*nu)*P*(c + y)*ATAN((c + y)/x))/(Pi*E) + 
 &  ((-1D0 + nu)*(1D0 + nu)*P*x*DLOG(x**2 + (c - y)**2))/(Pi*E) + 
 &  ((1D0 + nu)*P*(x - nu*x)*DLOG(x**2 + (c + y)**2))/(Pi*E)
>       

Here I have first string starting from 7-th columns (V=...), symbol & at 6-th position show continuation, 1->1D0, ArcTan->ATAN, Y->E, etc.

Answer 1

Warning: as @george points out in the comments, something is wrong with the output of this package. It produced incorrect d0d0. I don't have time to investigate at the moment, so making it community wiki. Feel free to post your own (corrected) answer based on the information here.

Using the Format.m package that @Orders posted,

expr = C3 (c - y) + 
   C3 (c + y) + ((1 + nu) (-1 + 2 nu) P (c - y) ArcTan[(-c + y)/
        x])/(π Y) + ((1 + nu) (-1 + 2 nu) P (c + 
        y) ArcTan[(c + y)/x])/(π Y) + ((-1 + nu) (1 + nu) P x Log[
       x^2 + (c - y)^2])/(π Y) + ((1 + nu) P (x - nu x) Log[
       x^2 + (c + y)^2])/(π Y);

FortranAssign["expr", expr, AssignReplace -> {"log" -> "dlog"}, AssignOptimize -> False]

gives the following

        expr = C3*(c - y) + C3*(c + y) + (3.183098861837907d-1*(1.d0 + n
     &  u)*(-1.d0d0 + 2.d0*nu)*P*(c - y)*atan((-c + y)/x))/Y + (3.183098
     &  861837907d-1*(1.d0 + nu)*(-1.d0d0 + 2.d0*nu)*P*(c + y)*atan((c +
     &   y)/x))/Y + (3.183098861837907d-1*(-1.d0d0 + nu)*(1.d0 + nu)*P*x
     &  *dlog((c - y)**2 + x*x))/Y + (3.183098861837907d-1*(1.d0 + nu)*P
     &  *(x - nu*x)*dlog((c + y)**2 + x*x))/Y

The 3.183d-1 you see here is simply a decimal approximation of 1/Pi to double precision.

We can also use automatic expression optimization, which changes the formula to an equivalent form that minimizes the number of arithmetic operations. For this it needs to use temporary variables, which I named tempXX here.

FortranAssign["expr", expr, AssignReplace -> {"log" -> "dlog"}, 
 "OptimizationSymbol" -> temp]

        temp1 = -y
        temp2 = c + temp1
        temp6 = 1.d0 + nu
        temp7 = 2.d0*nu
        temp8 = -1.d0d0 + temp7
        temp4 = c + y
        temp9 = 1/Y
        temp10 = 1/x
        temp20 = x*x
        expr = C3*temp2 + C3*temp4 + 3.183098861837907d-1*P*temp4*temp6*
     &  temp8*temp9*atan(temp10*temp4) + 3.183098861837907d-1*P*temp2*te
     &  mp6*temp8*temp9*atan(temp10*(-c + y)) + 3.183098861837907d-1*(-1
     &  .d0d0 + nu)*P*temp6*temp9*x*dlog(temp20 + temp2*temp2) + 3.18309
     &  8861837907d-1*P*temp6*temp9*(x - nu*x)*dlog(temp20 + temp4*temp4
     &  )

---

Getting the package to work in Mathematca 10:

If you try to load it as is, it will complain about not finding Utilities`FilterOptions`, a package that no longer ships with Mathematica 10. To fix this,

• Change BeginPackage["Format`", "Utilities`FilterOptions`"] to BeginPackage["Format`"].

• Add FilterOptions[fun_, opts___] := Sequence@@FilterRules[{opts}, Options[fun]] right after Begin["Private`"].