synced to 1.0

diff --git a/ginac/pseries.cpp b/ginac/pseries.cpp
index 8479735c18a6cb05c1c6687e72a1cbffeb53fd2b..b32953f43fb1b13ca9c9e09af631c8d9e7c155fa 100644 (file)
--- a/ginac/pseries.cpp
+++ b/ginac/pseries.cpp
@@ -446,14 +446,14 @@ ex pseries::expand(unsigned options) const
                ->setflag(status_flags::dynallocated | (options == 0 ? status_flags::expanded : 0));
 }
 
-/** Implementation of ex::diff() for a power series.  It treats the series as a
- *  polynomial.
+/** Implementation of ex::diff() for a power series.
  *  @see ex::diff */
 ex pseries::derivative(const symbol & s) const
 {
+       epvector new_seq;
+       epvector::const_iterator it = seq.begin(), itend = seq.end();
+
        if (s == var) {
-               epvector new_seq;
-               epvector::const_iterator it = seq.begin(), itend = seq.end();
                
                // FIXME: coeff might depend on var
                while (it != itend) {
@@ -466,10 +466,22 @@ ex pseries::derivative(const symbol & s) const
                        }
                        ++it;
                }
-               return pseries(relational(var,point), new_seq);
+
        } else {
-               return *this;
+
+               while (it != itend) {
+                       if (is_order_function(it->rest)) {
+                               new_seq.push_back(*it);
+                       } else {
+                               ex c = it->rest.diff(s);
+                               if (!c.is_zero())
+                                       new_seq.push_back(expair(c, it->coeff));
+                       }
+                       ++it;
+               }
        }
+
+       return pseries(relational(var,point), new_seq);
 }
 
 ex pseries::convert_to_poly(bool no_order) const