X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fbasic.cpp;h=5c3c147faf57d039fe57e94c9be0e2f92112d7bb;hp=e2a9320e9b098629017fff48aebfc35892292170;hb=857ca8ca24fbfe26d4c0c624aa6c3f2296c419f8;hpb=956eeb82c513a723e864edefa857133282cf692b

diff --git a/ginac/basic.cpp b/ginac/basic.cpp
index e2a9320e..5c3c147f 100644
--- a/ginac/basic.cpp
+++ b/ginac/basic.cpp
@@ -80,14 +80,7 @@ const basic & basic::operator=(const basic & other)
 
 // protected
 
-#if 0
-void basic::copy(const basic & other)
-{
-    flags=other.flags & ~ status_flags::dynallocated;
-    hashvalue=other.hashvalue;
-    tinfo_key=other.tinfo_key;
-}
-#endif
+// none (all inlined)
 
 //////////
 // other constructors
@@ -229,9 +222,9 @@ ex & basic::let_op(int i)
 
 ex basic::operator[](const ex & index) const
 {
-    if (is_exactly_of_type(*index.bp,numeric)) {
+    if (is_exactly_of_type(*index.bp,numeric))
         return op(static_cast<const numeric &>(*index.bp).to_int());
-    }
+    
     throw(std::invalid_argument("non-numeric indices not supported by this type"));
 }
 
@@ -240,6 +233,8 @@ ex basic::operator[](int i) const
     return op(i);
 }
 
+/** Search ocurrences.  An object  'has' an expression if it is the expression
+ *  itself or one of the children 'has' it. */
 bool basic::has(const ex & other) const
 {
     GINAC_ASSERT(other.bp!=0);
@@ -252,47 +247,81 @@ bool basic::has(const ex & other) const
     return false;
 }
 
+/** Return degree of highest power in symbol s. */
 int basic::degree(const symbol & s) const
 {
     return 0;
 }
 
+/** Return degree of lowest power in symbol s. */
 int basic::ldegree(const symbol & s) const
 {
     return 0;
 }
 
+/** Return coefficient of degree n in symbol s. */
 ex basic::coeff(const symbol & s, int n) const
 {
     return n==0 ? *this : _ex0();
 }
 
+/** Sort expression in terms of powers of some symbol.
+ *  @param s symbol to sort in. */
 ex basic::collect(const symbol & s) const
 {
     ex x;
-    int ldeg=ldegree(s);
-    int deg=degree(s);
+    int ldeg = this->ldegree(s);
+    int deg = this->degree(s);
     for (int n=ldeg; n<=deg; n++) {
-        x += coeff(s,n)*power(s,n);
+        x += this->coeff(s,n)*power(s,n);
     }
     return x;
 }
 
+/* Perform automatic symbolic evaluations on expression. */
 ex basic::eval(int level) const
 {
     return this->hold();
 }
 
+/** Evaluate object numerically. */
 ex basic::evalf(int level) const
 {
     return *this;
 }
 
+/* Substitute a set of symbols. */
 ex basic::subs(const lst & ls, const lst & lr) const
 {
     return *this;
 }
 
+/** Default interface of nth derivative ex::diff(s, n).  It should be called
+ *  instead of ::derivative(s) for first derivatives and for nth derivatives it
+ *  just recurses down.
+ *
+ *  @param s symbol to differentiate in
+ *  @param nth order of differentiation
+ *  @see ex::diff */
+ex basic::diff(const symbol & s, unsigned nth) const
+{
+    // trivial: zeroth derivative
+    if (!nth)
+        return ex(*this);
+    
+    // evaluate unevalueted *this before differentiating
+    if (!(flags & status_flags::evaluated))
+        return ex(*this).diff(s, nth);
+    
+    ex ndiff = derivative(s);
+    while (!ndiff.is_zero() &&    // stop differentiating zeros
+           nth>1) {
+        ndiff = ndiff.diff(s);
+        --nth;
+    }
+    return ndiff;
+}
+
 exvector basic::get_indices(void) const
 {
     return exvector(); // return an empty exvector
@@ -305,6 +334,15 @@ ex basic::simplify_ncmul(const exvector & v) const
 
 // protected
 
+/** Default implementation of ex::diff(). It simply throws an error message.
+ *
+ *  @exception logic_error (differentiation not supported by this type)
+ *  @see ex::diff */
+ex basic::derivative(const symbol & s) const
+{
+    throw(std::logic_error("differentiation not supported by this type"));
+}
+
 int basic::compare_same_type(const basic & other) const
 {
     return compare_pointers(this, &other);
@@ -344,24 +382,27 @@ unsigned basic::calchash(void) const
     return v;
 }
 
+/** Expand expression, i.e. multiply it out and return the result as a new
+ *  expression. */
 ex basic::expand(unsigned options) const
 {
     return this->setflag(status_flags::expanded);
 }
 
+
 //////////
 // non-virtual functions in this class
 //////////
 
 // public
 
+/** Substitute symbols in expression and return the result as a new expression.
+ *  There are two valid types of replacement arguments: 1) a relational like
+ *  symbol==ex and 2) a list of relationals lst(symbol1==ex1,symbol2==ex2,...),
+ *  which is converted to subs(lst(symbol1,symbol2,...),lst(ex1,ex2,...)).
+ *  In addition, an object of class idx can be used instead of a symbol. */
 ex basic::subs(const ex & e) const
 {
-    // accept 2 types of replacement expressions:
-    //   - symbol==ex
-    //   - lst(symbol1==ex1,symbol2==ex2,...)
-    // convert to subs(lst(symbol1,symbol2,...),lst(ex1,ex2,...))
-    // additionally, idx can be used instead of symbol
     if (e.info(info_flags::relation_equal)) {
         return subs(lst(e));
     }
@@ -438,6 +479,7 @@ int basic::compare(const basic & other) const
     return cmpval;
 }
 
+/** Test for equality. */
 bool basic::is_equal(const basic & other) const
 {
     unsigned hash_this = gethash();
@@ -457,6 +499,8 @@ bool basic::is_equal(const basic & other) const
 
 // protected
 
+/** Stop further evaluation.
+ *  @see basic::eval */
 const basic & basic::hold(void) const
 {
     return setflag(status_flags::evaluated);
@@ -475,8 +519,8 @@ void basic::ensure_if_modifiable(void) const
 
 // protected
 
-unsigned basic::precedence=70;
-unsigned basic::delta_indent=4;
+unsigned basic::precedence = 70;
+unsigned basic::delta_indent = 4;
 
 //////////
 // global constants