igraph requires -lblas and -llapack

[jdemeyer]

igraph doesn't build on some systems:

[igraph-0.7.1999] /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -lblas
[igraph-0.7.1999] /usr/lib/gcc/x86_64-pc-linux-gnu/4.9.3/../../../../x86_64-pc-linux-gnu/bin/ld: cannot find -llapack

Ideally, it should use OpenBLAS but it doesn't. Note that linking against OpenBLAS should be done with -lopenblas, not -lblas.

---

The use of blas/lapack in the (new) igraph is optional, so we just not use them in this branch.

We also specify the required in the (new) igraph package glpk in its dependencies.

CC: @dimpase

Component: packages: optional

Author: Dima Pasechnik

Branch/Commit: 28d375f

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/27597

[dimpase]

comment:1

in fact, it's entirely a bug introduced by me. The have very similar options
--with-glpk=external, --with-blas=external, meaning totally different things---cause they ship a version of glpk, but do not ship one for blas/lapack, which are actually optional.

So we should not link them at all (I won't try making an openblas version, I have no idea whether it's supported).

[dimpase]

Author: Dima Pasechnik

[fchapoton]

comment:2

This should be fixed as soon as possible, as it causes the patchbot sage4 to pollute every ticket with a wrong report.

[dimpase]

Commit: 37ccc83

[dimpase]

Branch: u/dimpase/packages/igraph_noblas

[jdemeyer]

comment:4

What about GLPK? If you want to use the GLPK in Sage, there should be a dependency on it.

[sagetrac-git]

Changed commit from 37ccc83 to 28d375f

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

28d375f

do not use blas/lapack with igraph

[dimpase]

Description changed:

--- 
+++ 
@@ -6,3 +6,9 @@
 ```
 
 Ideally, it *should* use OpenBLAS but it doesn't. Note that linking against OpenBLAS should be done with `-lopenblas`, not `-lblas`.
+
+---
+
+The use of blas/lapack in the (new) igraph is optional, so we just not use them in this branch.
+
+We also specify the required in the (new) igraph package glpk in its dependencies.