[BUG FIX] arpackmm: command line sanity checks.

CHANGES

@@ -15,7 +15,9 @@ arpack-ng - 3.9.0
  * use CMAKE_INSTALL_FULL_<dir> in arpack.pc
 
 [ Franck Houssen ]
+ * arpackmm: command line bug fix.
  * arpackmm: restart bug fix.
+
  -- Sylvestre Ledru <sylvestre@debian.org> Mon, 07 Dec 2020 11:37:40 +0100
 
 arpack-ng - 3.8.0

EXAMPLES/MATRIX_MARKET/arpackmm.cpp

@@ -316,6 +316,13 @@ class options {
       }
     }
 
+    // Sanity checks.
+
+    if (!stdPb && fileB.empty()) {
+      cerr << "Error: generalized problem without B matrix" << endl;
+      return usage();
+    }
+
     return 0;
   };