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[ginac.git] / ginac / matrix.cpp

diff --git a/ginac/matrix.cpp b/ginac/matrix.cpp
index 3f3b2e6fa93b34edaca43a427d94487db91bcd12..038084b6486e363ea38b02987fb02268793754dc 100644 (file)
--- a/ginac/matrix.cpp
+++ b/ginac/matrix.cpp
@@ -3,7 +3,7 @@
  *  Implementation of symbolic matrices */
 
 /*
- *  GiNaC Copyright (C) 1999-2006 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2007 Johannes Gutenberg University Mainz, Germany
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -113,12 +113,13 @@ matrix::matrix(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
        if (!(n.find_unsigned("row", row)) || !(n.find_unsigned("col", col)))
                throw (std::runtime_error("unknown matrix dimensions in archive"));
        m.reserve(row * col);
-       for (unsigned int i=0; true; i++) {
+       archive_node::archive_node_cit first = n.find_first("m");
+       archive_node::archive_node_cit last = n.find_last("m");
+       ++last;
+       for (archive_node::archive_node_cit i=first; i<last; ++i) {
                ex e;
-               if (n.find_ex("m", e, sym_lst, i))
-                       m.push_back(e);
-               else
-                       break;
+               n.find_ex_by_loc(i, e, sym_lst);
+               m.push_back(e);
        }
 }
 
@@ -1527,6 +1528,16 @@ int matrix::pivot(unsigned ro, unsigned co, bool symbolic)
        return k;
 }
 
+/** Function to check that all elements of the matrix are zero.
+ */
+bool matrix::is_zero_matrix() const
+{
+       for (exvector::const_iterator i=m.begin(); i!=m.end(); ++i) 
+               if(!(i->is_zero()))
+                       return false;
+       return true;
+}
+
 ex lst_to_matrix(const lst & l)
 {
        lst::const_iterator itr, itc;