[MacPorts] #60153: eigen3 at 3.3.7: Variants missing/unclear.

[MacPorts]

#60153: eigen3 at 3.3.7: Variants missing/unclear.
--------------------------+--------------------
  Reporter:  AndyWharton  |      Owner:  (none)
      Type:  defect       |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.6.2
Resolution:               |   Keywords:
      Port:  eigen3       |
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Comment (by eborisch):

 Eigen is by default a header-only install, and no compilers are needed.

 If you want to install a compiled BLAS library (+blas) based on Eigen, c++
 for compiling the actual library, and fortran (for bindings, if I recall)
 are needed. But the entire remainder (outside libeigen_blas*) of the Eigen
 installation remains header-only. I tried to document that with:
 `blas: Build eigen's blas (libeigen_blas*) : needs +gccNN, +g95, or
 +gfortran`

 It uses the compilers port group to provide all the different compilers
 available, so I believe the actual variants available change some based on
 the OS version.

 If you want documentation, it uses a compiler again to compile and run
 code used in the documentation.

 Hope that helps.

-- 
Ticket URL: <https://trac.macports.org/ticket/60153#comment:1>
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