- added idx::replace_dim() and idx::minimal_dim()

[ginac.git] / ginac / idx.cpp

diff --git a/ginac/idx.cpp b/ginac/idx.cpp
index a3767fe8c5c65e7dc357e712cf79b34756737347..6a9ac8ae3ad33250c10e8a2a2dcc04ce8c1b9d47 100644 (file)
--- a/ginac/idx.cpp
+++ b/ginac/idx.cpp
@@ -26,6 +26,7 @@
 #include "idx.h"
 #include "symbol.h"
 #include "lst.h"
+#include "relational.h"
 #include "print.h"
 #include "archive.h"
 #include "utils.h"
@@ -394,7 +395,8 @@ bool idx::is_dummy_pair_same_type(const basic & other) const
 {
        const idx &o = static_cast<const idx &>(other);
 
-       // Only pure symbols form dummy pairs, "2n+1" doesn't
+       // Only pure symbols form dummy pairs, numeric indices and expressions
+       // like "2n+1" don't
        if (!is_ex_of_type(value, symbol))
                return false;
 
@@ -402,8 +404,12 @@ bool idx::is_dummy_pair_same_type(const basic & other) const
        if (!value.is_equal(o.value))
                return false;
 
-       // Also the dimension
-       return dim.is_equal(o.dim);
+       // Dimensions need not be equal but must be comparable (so we can
+       // determine the minimum dimension of contractions)
+       if (dim.is_equal(o.dim))
+               return true;
+
+       return (dim < o.dim || dim > o.dim);
 }
 
 bool varidx::is_dummy_pair_same_type(const basic & other) const
@@ -433,6 +439,24 @@ bool spinidx::is_dummy_pair_same_type(const basic & other) const
 // non-virtual functions
 //////////
 
+ex idx::replace_dim(const ex & new_dim) const
+{
+       idx *i_copy = static_cast<idx *>(duplicate());
+       i_copy->dim = new_dim;
+       i_copy->clearflag(status_flags::hash_calculated);
+       return i_copy->setflag(status_flags::dynallocated);
+}
+
+ex idx::minimal_dim(const idx & other) const
+{
+       if (dim.is_equal(other.dim) || dim < other.dim)
+               return dim;
+       else if (dim > other.dim)
+               return other.dim;
+       else
+               throw (std::runtime_error("idx::minimal_dim: index dimensions cannot be ordered"));
+}
+
 ex varidx::toggle_variance(void) const
 {
        varidx *i_copy = static_cast<varidx *>(duplicate());