moved even more duplicated code to the 'tensor' class

diff --git a/ginac/tensor.cpp b/ginac/tensor.cpp
index b71f6b037c0c9cfbe19e0dfe30bd734fe2ef51f5..a4ae63e05a70cbd5e5d6ae3461399123dcf7c6dd 100644 (file)
--- a/ginac/tensor.cpp
+++ b/ginac/tensor.cpp
@@ -443,15 +443,9 @@ ex tensepsilon::eval_indexed(const basic & i) const
        return i.hold();
 }
 
-/** Contraction of an indexed delta tensor with something else. */
-bool tensdelta::contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const
+bool tensor::replace_contr_index(exvector::iterator self, exvector::iterator other) const
 {
-       GINAC_ASSERT(is_a<indexed>(*self));
-       GINAC_ASSERT(is_a<indexed>(*other));
-       GINAC_ASSERT(self->nops() == 3);
-       GINAC_ASSERT(is_a<tensdelta>(self->op(0)));
-
-       // Try to contract first index
+       // Try to contract the first index
        const idx *self_idx = &ex_to<idx>(self->op(1));
        const idx *free_idx = &ex_to<idx>(self->op(2));
        bool first_index_tried = false;
@@ -462,8 +456,8 @@ again:
                        const idx &other_idx = ex_to<idx>(other->op(i));
                        if (is_dummy_pair(*self_idx, other_idx)) {
 
-                               // Contraction found, remove delta tensor and substitute
-                               // index in second object
+                               // Contraction found, remove this tensor and substitute the
+                               // index in the second object
                                *self = _ex1;
                                *other = other->subs(other_idx == *free_idx);
                                return true;
@@ -473,7 +467,7 @@ again:
 
        if (!first_index_tried) {
 
-               // No contraction with first index found, try second index
+               // No contraction with the first index found, try the second index
                self_idx = &ex_to<idx>(self->op(2));
                free_idx = &ex_to<idx>(self->op(1));
                first_index_tried = true;
@@ -483,6 +477,19 @@ again:
        return false;
 }
 
+/** Contraction of an indexed delta tensor with something else. */
+bool tensdelta::contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const
+{
+       GINAC_ASSERT(is_a<indexed>(*self));
+       GINAC_ASSERT(is_a<indexed>(*other));
+       GINAC_ASSERT(self->nops() == 3);
+       GINAC_ASSERT(is_a<tensdelta>(self->op(0)));
+
+       // Replace the dummy index with this tensor's other index and remove
+       // the tensor (this is valid for contractions with all other tensors)
+       return replace_contr_index(self, other);
+}
+
 /** Contraction of an indexed 4-dimensional delta tensor with something else. */
 bool tens4delta::contract_with(exvector::iterator self, exvector::iterator other, exvector & v) const
 {
@@ -495,36 +502,9 @@ bool tens4delta::contract_with(exvector::iterator self, exvector::iterator other
        if (!(is_a<tens4delta>(other->op(0)) || is_a<mink4metric>(other->op(0)) || is_a<tensepsilon>(other->op(0))))
                return false;
 
-       // Try to contract first index
-       const idx *self_idx = &ex_to<idx>(self->op(1));
-       const idx *free_idx = &ex_to<idx>(self->op(2));
-       bool first_index_tried = false;
-
-again:
-       if (self_idx->is_symbolic()) {
-               for (unsigned i=1; i<other->nops(); i++) {
-                       const idx &other_idx = ex_to<idx>(other->op(i));
-                       if (is_dummy_pair(*self_idx, other_idx)) {
-
-                               // Contraction found, remove delta tensor and substitute
-                               // index in second object
-                               *self = _ex1;
-                               *other = other->subs(other_idx == *free_idx);
-                               return true;
-                       }
-               }
-       }
-
-       if (!first_index_tried) {
-
-               // No contraction with first index found, try second index
-               self_idx = &ex_to<idx>(self->op(2));
-               free_idx = &ex_to<idx>(self->op(1));
-               first_index_tried = true;
-               goto again;
-       }
-
-       return false;
+       // Replace the dummy index with this tensor's other index and remove
+       // the tensor
+       return replace_contr_index(self, other);
 }
 
 /** Contraction of an indexed metric tensor with something else. */
@@ -540,36 +520,9 @@ bool tensmetric::contract_with(exvector::iterator self, exvector::iterator other
        if (is_a<tensdelta>(other->op(0)))
                return false;
 
-       // Try to contract first index
-       const idx *self_idx = &ex_to<idx>(self->op(1));
-       const idx *free_idx = &ex_to<idx>(self->op(2));
-       bool first_index_tried = false;
-
-again:
-       if (self_idx->is_symbolic()) {
-               for (unsigned i=1; i<other->nops(); i++) {
-                       const idx &other_idx = ex_to<idx>(other->op(i));
-                       if (is_dummy_pair(*self_idx, other_idx)) {
-
-                               // Contraction found, remove metric tensor and substitute
-                               // index in second object
-                               *self = _ex1;
-                               *other = other->subs(other_idx == *free_idx);
-                               return true;
-                       }
-               }
-       }
-
-       if (!first_index_tried) {
-
-               // No contraction with first index found, try second index
-               self_idx = &ex_to<idx>(self->op(2));
-               free_idx = &ex_to<idx>(self->op(1));
-               first_index_tried = true;
-               goto again;
-       }
-
-       return false;
+       // Replace the dummy index with this tensor's other index and remove
+       // the tensor
+       return replace_contr_index(self, other);
 }
 
 /** Contraction of an indexed 4-dimensional Lorentz metric tensor with something else. */
@@ -584,36 +537,9 @@ bool mink4metric::contract_with(exvector::iterator self, exvector::iterator othe
        if (!(is_a<mink4metric>(other->op(0)) || is_a<tensepsilon>(other->op(0))))
                return false;
 
-       // Try to contract first index
-       const idx *self_idx = &ex_to<idx>(self->op(1));
-       const idx *free_idx = &ex_to<idx>(self->op(2));
-       bool first_index_tried = false;
-
-again:
-       if (self_idx->is_symbolic()) {
-               for (unsigned i=1; i<other->nops(); i++) {
-                       const idx &other_idx = ex_to<idx>(other->op(i));
-                       if (is_dummy_pair(*self_idx, other_idx)) {
-
-                               // Contraction found, remove metric tensor and substitute
-                               // index in second object
-                               *self = _ex1;
-                               *other = other->subs(other_idx == *free_idx);
-                               return true;
-                       }
-               }
-       }
-
-       if (!first_index_tried) {
-
-               // No contraction with first index found, try second index
-               self_idx = &ex_to<idx>(self->op(2));
-               free_idx = &ex_to<idx>(self->op(1));
-               first_index_tried = true;
-               goto again;
-       }
-
-       return false;
+       // Replace the dummy index with this tensor's other index and remove
+       // the tensor
+       return replace_contr_index(self, other);
 }
 
 

diff --git a/ginac/tensor.h b/ginac/tensor.h
index d3b3a136445c24945803a7122bf15a96204391ac..2fa8e661ff249b8fdbaf82c90ba41db8f81716a5 100644 (file)
--- a/ginac/tensor.h
+++ b/ginac/tensor.h
@@ -42,6 +42,13 @@ protected:
        // functions overriding virtual functions from base classes
 protected:
        unsigned return_type(void) const { return return_types::noncommutative_composite; }
+
+       // non-virtual functions in this class
+public:
+       /** Replace dummy index in contracted-with object by the contracting
+        *  object's second index (used internally for delta and metric tensor
+        *  contractions. */
+       bool replace_contr_index(exvector::iterator self, exvector::iterator other) const;
 };