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Hi Everyone!

I'm using Fortran 90 and trying to use the library nlopt.f in my code.
I downloaded the library from NLopt on Windows from http://ab-initio.mit.edu/wiki/index.php/NLopt_on_W...

After downloading the zip code from there I went to the DOS command option and run the line: lib /def:libnlopt-0.def (as suggested by wikipedia). However, I am still not able to use it in my code.

I am using compaq Visual Fortran to code.

I am not sure how to install the library on my computer so that when I write in my code include nlopt.f, I will be able to use the functions that the library has. Can anyone help with this problem?

Thanks in advance,

RE: nlopt.f

I have not Visual Fortran compiler, but with the gfortran compiler it works for me as following:
1. I downloaded the package nlopt-2.4.2-dll32.zip from here

2. I extracted the package and copied from it these 2 files into my working directory:

3. For trying if it works I took the code from here
and created nlopt_example.f95

Now I have in my working dorectory these 3 files



4. I compiled the example using this command line


$ gfortran nlopt_example.f95 -o nlopt_example -L. libnlopt-0.dll 
which created the nlopt_example.exe

5. when I run the exe I get the result


$ nlopt_example
 found min at   0.33333333454526648       0.29629628990899065
 min val =   0.54433104808470245 

RE: nlopt.f

Here is the source I used:



! Compile:
! gfortran nlopt_example.f95 -o nlopt_example -L. libnlopt-0.dll
program main
  external myfunc, myconstraint
  double precision lb(2)
  integer*8 opt
  double precision d1(2), d2(2)
  double precision x(2), minf
  integer ires
  include 'nlopt.f'
  call nlo_create(opt, NLOPT_LD_MMA, 2)
  call nlo_get_lower_bounds(ires, opt, lb)
  lb(2) = 0.0
  call nlo_set_lower_bounds(ires, opt, lb)
  call nlo_set_min_objective(ires, opt, myfunc, 0)
  d1(1) = 2.
  d1(2) = 0.
  call nlo_add_inequality_constraint(ires, opt, &
       myconstraint, d1, 1.D-8)
  d2(1) = -1.
  d2(2) = 1.
  call nlo_add_inequality_constraint(ires, opt, &
       myconstraint, d2, 1.D-8)
  call nlo_set_xtol_rel(ires, opt, 1.D-4)
  x(1) = 1.234
  x(2) = 5.678
  call nlo_optimize(ires, opt, x, minf)
  if (ires.lt.0) then
     write(*,*) 'nlopt failed!'
     write(*,*) 'found min at ', x(1), x(2)
     write(*,*) 'min val = ', minf

  call nlo_destroy(opt)

subroutine myfunc(val, n, x, grad, need_gradient, f_data)
  double precision val, x(n), grad(n)
  integer n, need_gradient
  if (need_gradient.ne.0) then
     grad(1) = 0.0
     grad(2) = 0.5 / dsqrt(x(2))
  val = dsqrt(x(2))

subroutine myconstraint(val, n, x, grad, need_gradient, d)
  integer need_gradient
  double precision val, x(n), grad(n), d(2), a, b
  a = d(1)
  b = d(2)
  if (need_gradient.ne.0) then
     grad(1) = 3. * a * (a*x(1) + b)**2
     grad(2) = -1.0
  val = (a*x(1) + b)**3 - x(2)

RE: nlopt.f

Thank you for your help!

I did everything you are saying except I don't understand what it means in step 2 to add the files into the directory. Where do you add them exactly? How do you do that?

Also what do you mean by compiling here? In your code the compile line has a ! so it is actually just a remark....So I am not sure what you mean by that either. Can you expand on that?

Thanks so much in advance,

RE: nlopt.f

Quote (shaberg)

I don't understand what it means in step 2 to add the files into the directory
I copied the 2 files (libnlopt-0.dll and nlopt.f) into my working directory, which is


It's so long because I'm using MingW + MSYS (see http://www.mingw.org/wiki/msys)


Also what do you mean by compiling here? In your code the compile line has a ! so it is actually just a remark....
Yes, I remarked in the fortran code too, how to compile it.
First, I changed to my working directory (i.e.: C:\MinGW\msys\1.0\home\Roman\fortran\nlopt) and then I compiled it executing the command:


gfortran nlopt_example.f95 -o nlopt_example -L. libnlopt-0.dll 

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