]> www.ginac.de Git - ginac.git/blobdiff - ginac/matrix.cpp
Added a document about the coding conventions used in GiNaC. Corrections,
[ginac.git] / ginac / matrix.cpp
index 3e0eeaf84ded4d106b4070856c2ca91020046400..2c191ff4f69c04d993b2724b16f13e13d445156e 100644 (file)
@@ -3,7 +3,7 @@
  *  Implementation of symbolic matrices */
 
 /*
- *  GiNaC Copyright (C) 1999-2000 Johannes Gutenberg University Mainz, Germany
+ *  GiNaC Copyright (C) 1999-2003 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
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
+#include <string>
+#include <iostream>
+#include <sstream>
 #include <algorithm>
 #include <map>
 #include <stdexcept>
 
 #include "matrix.h"
-#include "archive.h"
 #include "numeric.h"
 #include "lst.h"
-#include "utils.h"
-#include "debugmsg.h"
+#include "idx.h"
+#include "indexed.h"
+#include "add.h"
 #include "power.h"
 #include "symbol.h"
+#include "operators.h"
 #include "normal.h"
+#include "archive.h"
+#include "utils.h"
 
-#ifndef NO_NAMESPACE_GINAC
 namespace GiNaC {
-#endif // ndef NO_NAMESPACE_GINAC
 
-GINAC_IMPLEMENT_REGISTERED_CLASS(matrix, basic)
+GINAC_IMPLEMENT_REGISTERED_CLASS_OPT(matrix, basic,
+  print_func<print_context>(&matrix::do_print).
+  print_func<print_latex>(&matrix::do_print_latex).
+  print_func<print_tree>(&basic::do_print_tree).
+  print_func<print_python_repr>(&matrix::do_print_python_repr))
 
 //////////
-// default constructor, destructor, copy constructor, assignment operator
-// and helpers:
+// default constructor
 //////////
 
-// public
-
 /** Default ctor.  Initializes to 1 x 1-dimensional zero-matrix. */
-matrix::matrix() : inherited(TINFO_matrix), row(1), col(1)
+matrix::matrix() : inherited(TINFO_matrix), row(1), col(1), m(1, _ex0)
 {
-       debugmsg("matrix default constructor",LOGLEVEL_CONSTRUCT);
-       m.push_back(_ex0());
-}
-
-matrix::~matrix()
-{
-       debugmsg("matrix destructor",LOGLEVEL_DESTRUCT);
-       destroy(false);
-}
-
-matrix::matrix(const matrix & other)
-{
-       debugmsg("matrix copy constructor",LOGLEVEL_CONSTRUCT);
-       copy(other);
-}
-
-const matrix & matrix::operator=(const matrix & other)
-{
-       debugmsg("matrix operator=",LOGLEVEL_ASSIGNMENT);
-       if (this != &other) {
-               destroy(true);
-               copy(other);
-       }
-       return *this;
-}
-
-// protected
-
-void matrix::copy(const matrix & other)
-{
-       inherited::copy(other);
-       row = other.row;
-       col = other.col;
-       m = other.m;  // STL's vector copying invoked here
-}
-
-void matrix::destroy(bool call_parent)
-{
-       if (call_parent) inherited::destroy(call_parent);
+       setflag(status_flags::not_shareable);
 }
 
 //////////
@@ -102,10 +69,9 @@ void matrix::destroy(bool call_parent)
  *  @param r number of rows
  *  @param c number of cols */
 matrix::matrix(unsigned r, unsigned c)
-  : inherited(TINFO_matrix), row(r), col(c)
+  : inherited(TINFO_matrix), row(r), col(c), m(r*c, _ex0)
 {
-       debugmsg("matrix constructor from unsigned,unsigned",LOGLEVEL_CONSTRUCT);
-       m.resize(r*c, _ex0());
+       setflag(status_flags::not_shareable);
 }
 
 // protected
@@ -114,17 +80,36 @@ matrix::matrix(unsigned r, unsigned c)
 matrix::matrix(unsigned r, unsigned c, const exvector & m2)
   : inherited(TINFO_matrix), row(r), col(c), m(m2)
 {
-       debugmsg("matrix constructor from unsigned,unsigned,exvector",LOGLEVEL_CONSTRUCT);
+       setflag(status_flags::not_shareable);
+}
+
+/** Construct matrix from (flat) list of elements. If the list has fewer
+ *  elements than the matrix, the remaining matrix elements are set to zero.
+ *  If the list has more elements than the matrix, the excessive elements are
+ *  thrown away. */
+matrix::matrix(unsigned r, unsigned c, const lst & l)
+  : inherited(TINFO_matrix), row(r), col(c), m(r*c, _ex0)
+{
+       setflag(status_flags::not_shareable);
+
+       size_t i = 0;
+       for (lst::const_iterator it = l.begin(); it != l.end(); ++it, ++i) {
+               size_t x = i % c;
+               size_t y = i / c;
+               if (y >= r)
+                       break; // matrix smaller than list: throw away excessive elements
+               m[y*c+x] = *it;
+       }
 }
 
 //////////
 // archiving
 //////////
 
-/** Construct object from archive_node. */
-matrix::matrix(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst)
+matrix::matrix(const archive_node &n, lst &sym_lst) : inherited(n, sym_lst)
 {
-       debugmsg("matrix constructor from archive_node", LOGLEVEL_CONSTRUCT);
+       setflag(status_flags::not_shareable);
+
        if (!(n.find_unsigned("row", row)) || !(n.find_unsigned("col", col)))
                throw (std::runtime_error("unknown matrix dimensions in archive"));
        m.reserve(row * col);
@@ -137,13 +122,6 @@ matrix::matrix(const archive_node &n, const lst &sym_lst) : inherited(n, sym_lst
        }
 }
 
-/** Unarchive the object. */
-ex matrix::unarchive(const archive_node &n, const lst &sym_lst)
-{
-       return (new matrix(n, sym_lst))->setflag(status_flags::dynallocated);
-}
-
-/** Archive the object. */
 void matrix::archive(archive_node &n) const
 {
        inherited::archive(n);
@@ -156,102 +134,77 @@ void matrix::archive(archive_node &n) const
        }
 }
 
+DEFAULT_UNARCHIVE(matrix)
+
 //////////
-// functions overriding virtual functions from bases classes
+// functions overriding virtual functions from base classes
 //////////
 
 // public
 
-basic * matrix::duplicate() const
+void matrix::print_elements(const print_context & c, const char *row_start, const char *row_end, const char *row_sep, const char *col_sep) const
 {
-       debugmsg("matrix duplicate",LOGLEVEL_DUPLICATE);
-       return new matrix(*this);
+       for (unsigned ro=0; ro<row; ++ro) {
+               c.s << row_start;
+               for (unsigned co=0; co<col; ++co) {
+                       m[ro*col+co].print(c);
+                       if (co < col-1)
+                               c.s << col_sep;
+                       else
+                               c.s << row_end;
+               }
+               if (ro < row-1)
+                       c.s << row_sep;
+       }
 }
 
-void matrix::print(std::ostream & os, unsigned upper_precedence) const
+void matrix::do_print(const print_context & c, unsigned level) const
 {
-       debugmsg("matrix print",LOGLEVEL_PRINT);
-       os << "[[ ";
-       for (unsigned r=0; r<row-1; ++r) {
-               os << "[[";
-               for (unsigned c=0; c<col-1; ++c)
-                       os << m[r*col+c] << ",";
-               os << m[col*(r+1)-1] << "]], ";
-       }
-       os << "[[";
-       for (unsigned c=0; c<col-1; ++c)
-               os << m[(row-1)*col+c] << ",";
-       os << m[row*col-1] << "]] ]]";
+       c.s << "[";
+       print_elements(c, "[", "]", ",", ",");
+       c.s << "]";
 }
 
-void matrix::printraw(std::ostream & os) const
+void matrix::do_print_latex(const print_latex & c, unsigned level) const
 {
-       debugmsg("matrix printraw",LOGLEVEL_PRINT);
-       os << "matrix(" << row << "," << col <<",";
-       for (unsigned r=0; r<row-1; ++r) {
-               os << "(";
-               for (unsigned c=0; c<col-1; ++c)
-                       os << m[r*col+c] << ",";
-               os << m[col*(r-1)-1] << "),";
-       }
-       os << "(";
-       for (unsigned c=0; c<col-1; ++c)
-               os << m[(row-1)*col+c] << ",";
-       os << m[row*col-1] << "))";
+       c.s << "\\left(\\begin{array}{" << std::string(col,'c') << "}";
+       print_elements(c, "", "", "\\\\", "&");
+       c.s << "\\end{array}\\right)";
 }
 
-/** nops is defined to be rows x columns. */
-unsigned matrix::nops() const
+void matrix::do_print_python_repr(const print_python_repr & c, unsigned level) const
 {
-       return row*col;
+       c.s << class_name() << '(';
+       print_elements(c, "[", "]", ",", ",");
+       c.s << ')';
 }
 
-/** returns matrix entry at position (i/col, i%col). */
-ex matrix::op(int i) const
+/** nops is defined to be rows x columns. */
+size_t matrix::nops() const
 {
-       return m[i];
+       return static_cast<size_t>(row) * static_cast<size_t>(col);
 }
 
 /** returns matrix entry at position (i/col, i%col). */
-ex & matrix::let_op(int i)
+ex matrix::op(size_t i) const
 {
-       GINAC_ASSERT(i>=0);
        GINAC_ASSERT(i<nops());
        
        return m[i];
 }
 
-/** expands the elements of a matrix entry by entry. */
-ex matrix::expand(unsigned options) const
-{
-       exvector tmp(row*col);
-       for (unsigned i=0; i<row*col; ++i)
-               tmp[i] = m[i].expand(options);
-       
-       return matrix(row, col, tmp);
-}
-
-/** Search ocurrences.  A matrix 'has' an expression if it is the expression
- *  itself or one of the elements 'has' it. */
-bool matrix::has(const ex & other) const
+/** returns writable matrix entry at position (i/col, i%col). */
+ex & matrix::let_op(size_t i)
 {
-       GINAC_ASSERT(other.bp!=0);
-       
-       // tautology: it is the expression itself
-       if (is_equal(*other.bp)) return true;
-       
-       // search all the elements
-       for (exvector::const_iterator r=m.begin(); r!=m.end(); ++r)
-               if ((*r).has(other)) return true;
+       GINAC_ASSERT(i<nops());
        
-       return false;
+       ensure_if_modifiable();
+       return m[i];
 }
 
-/** evaluate matrix entry by entry. */
+/** Evaluate matrix entry by entry. */
 ex matrix::eval(int level) const
 {
-       debugmsg("matrix eval",LOGLEVEL_MEMBER_FUNCTION);
-       
        // check if we have to do anything at all
        if ((level==1)&&(flags & status_flags::evaluated))
                return *this;
@@ -268,39 +221,25 @@ ex matrix::eval(int level) const
                        m2[r*col+c] = m[r*col+c].eval(level);
        
        return (new matrix(row, col, m2))->setflag(status_flags::dynallocated |
-                                                                                          status_flags::evaluated );
+                                                                                          status_flags::evaluated);
 }
 
-/** evaluate matrix numerically entry by entry. */
-ex matrix::evalf(int level) const
+ex matrix::subs(const exmap & mp, unsigned options) const
 {
-       debugmsg("matrix evalf",LOGLEVEL_MEMBER_FUNCTION);
-               
-       // check if we have to do anything at all
-       if (level==1)
-               return *this;
-       
-       // emergency break
-       if (level == -max_recursion_level) {
-               throw (std::runtime_error("matrix::evalf(): recursion limit exceeded"));
-       }
-       
-       // evalf() entry by entry
-       exvector m2(row*col);
-       --level;
+       exvector m2(row * col);
        for (unsigned r=0; r<row; ++r)
                for (unsigned c=0; c<col; ++c)
-                       m2[r*col+c] = m[r*col+c].evalf(level);
-       
-       return matrix(row, col, m2);
+                       m2[r*col+c] = m[r*col+c].subs(mp, options);
+
+       return matrix(row, col, m2).subs_one_level(mp, options);
 }
 
 // protected
 
 int matrix::compare_same_type(const basic & other) const
 {
-       GINAC_ASSERT(is_exactly_of_type(other, matrix));
-       const matrix & o = static_cast<matrix &>(const_cast<basic &>(other));
+       GINAC_ASSERT(is_exactly_a<matrix>(other));
+       const matrix &o = static_cast<const matrix &>(other);
        
        // compare number of rows
        if (row != o.rows())
@@ -322,6 +261,243 @@ int matrix::compare_same_type(const basic & other) const
        return 0;
 }
 
+bool matrix::match_same_type(const basic & other) const
+{
+       GINAC_ASSERT(is_exactly_a<matrix>(other));
+       const matrix & o = static_cast<const matrix &>(other);
+       
+       // The number of rows and columns must be the same. This is necessary to
+       // prevent a 2x3 matrix from matching a 3x2 one.
+       return row == o.rows() && col == o.cols();
+}
+
+/** Automatic symbolic evaluation of an indexed matrix. */
+ex matrix::eval_indexed(const basic & i) const
+{
+       GINAC_ASSERT(is_a<indexed>(i));
+       GINAC_ASSERT(is_a<matrix>(i.op(0)));
+
+       bool all_indices_unsigned = static_cast<const indexed &>(i).all_index_values_are(info_flags::nonnegint);
+
+       // Check indices
+       if (i.nops() == 2) {
+
+               // One index, must be one-dimensional vector
+               if (row != 1 && col != 1)
+                       throw (std::runtime_error("matrix::eval_indexed(): vector must have exactly 1 index"));
+
+               const idx & i1 = ex_to<idx>(i.op(1));
+
+               if (col == 1) {
+
+                       // Column vector
+                       if (!i1.get_dim().is_equal(row))
+                               throw (std::runtime_error("matrix::eval_indexed(): dimension of index must match number of vector elements"));
+
+                       // Index numeric -> return vector element
+                       if (all_indices_unsigned) {
+                               unsigned n1 = ex_to<numeric>(i1.get_value()).to_int();
+                               if (n1 >= row)
+                                       throw (std::runtime_error("matrix::eval_indexed(): value of index exceeds number of vector elements"));
+                               return (*this)(n1, 0);
+                       }
+
+               } else {
+
+                       // Row vector
+                       if (!i1.get_dim().is_equal(col))
+                               throw (std::runtime_error("matrix::eval_indexed(): dimension of index must match number of vector elements"));
+
+                       // Index numeric -> return vector element
+                       if (all_indices_unsigned) {
+                               unsigned n1 = ex_to<numeric>(i1.get_value()).to_int();
+                               if (n1 >= col)
+                                       throw (std::runtime_error("matrix::eval_indexed(): value of index exceeds number of vector elements"));
+                               return (*this)(0, n1);
+                       }
+               }
+
+       } else if (i.nops() == 3) {
+
+               // Two indices
+               const idx & i1 = ex_to<idx>(i.op(1));
+               const idx & i2 = ex_to<idx>(i.op(2));
+
+               if (!i1.get_dim().is_equal(row))
+                       throw (std::runtime_error("matrix::eval_indexed(): dimension of first index must match number of rows"));
+               if (!i2.get_dim().is_equal(col))
+                       throw (std::runtime_error("matrix::eval_indexed(): dimension of second index must match number of columns"));
+
+               // Pair of dummy indices -> compute trace
+               if (is_dummy_pair(i1, i2))
+                       return trace();
+
+               // Both indices numeric -> return matrix element
+               if (all_indices_unsigned) {
+                       unsigned n1 = ex_to<numeric>(i1.get_value()).to_int(), n2 = ex_to<numeric>(i2.get_value()).to_int();
+                       if (n1 >= row)
+                               throw (std::runtime_error("matrix::eval_indexed(): value of first index exceeds number of rows"));
+                       if (n2 >= col)
+                               throw (std::runtime_error("matrix::eval_indexed(): value of second index exceeds number of columns"));
+                       return (*this)(n1, n2);
+               }
+
+       } else
+               throw (std::runtime_error("matrix::eval_indexed(): matrix must have exactly 2 indices"));
+
+       return i.hold();
+}
+
+/** Sum of two indexed matrices. */
+ex matrix::add_indexed(const ex & self, const ex & other) const
+{
+       GINAC_ASSERT(is_a<indexed>(self));
+       GINAC_ASSERT(is_a<matrix>(self.op(0)));
+       GINAC_ASSERT(is_a<indexed>(other));
+       GINAC_ASSERT(self.nops() == 2 || self.nops() == 3);
+
+       // Only add two matrices
+       if (is_a<matrix>(other.op(0))) {
+               GINAC_ASSERT(other.nops() == 2 || other.nops() == 3);
+
+               const matrix &self_matrix = ex_to<matrix>(self.op(0));
+               const matrix &other_matrix = ex_to<matrix>(other.op(0));
+
+               if (self.nops() == 2 && other.nops() == 2) { // vector + vector
+
+                       if (self_matrix.row == other_matrix.row)
+                               return indexed(self_matrix.add(other_matrix), self.op(1));
+                       else if (self_matrix.row == other_matrix.col)
+                               return indexed(self_matrix.add(other_matrix.transpose()), self.op(1));
+
+               } else if (self.nops() == 3 && other.nops() == 3) { // matrix + matrix
+
+                       if (self.op(1).is_equal(other.op(1)) && self.op(2).is_equal(other.op(2)))
+                               return indexed(self_matrix.add(other_matrix), self.op(1), self.op(2));
+                       else if (self.op(1).is_equal(other.op(2)) && self.op(2).is_equal(other.op(1)))
+                               return indexed(self_matrix.add(other_matrix.transpose()), self.op(1), self.op(2));
+
+               }
+       }
+
+       // Don't know what to do, return unevaluated sum
+       return self + other;
+}
+
+/** Product of an indexed matrix with a number. */
+ex matrix::scalar_mul_indexed(const ex & self, const numeric & other) const
+{
+       GINAC_ASSERT(is_a<indexed>(self));
+       GINAC_ASSERT(is_a<matrix>(self.op(0)));
+       GINAC_ASSERT(self.nops() == 2 || self.nops() == 3);
+
+       const matrix &self_matrix = ex_to<matrix>(self.op(0));
+
+       if (self.nops() == 2)
+               return indexed(self_matrix.mul(other), self.op(1));
+       else // self.nops() == 3
+               return indexed(self_matrix.mul(other), self.op(1), self.op(2));
+}
+
+/** Contraction of an indexed matrix with something else. */
+bool matrix::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() == 2 || self->nops() == 3);
+       GINAC_ASSERT(is_a<matrix>(self->op(0)));
+
+       // Only contract with other matrices
+       if (!is_a<matrix>(other->op(0)))
+               return false;
+
+       GINAC_ASSERT(other->nops() == 2 || other->nops() == 3);
+
+       const matrix &self_matrix = ex_to<matrix>(self->op(0));
+       const matrix &other_matrix = ex_to<matrix>(other->op(0));
+
+       if (self->nops() == 2) {
+
+               if (other->nops() == 2) { // vector * vector (scalar product)
+
+                       if (self_matrix.col == 1) {
+                               if (other_matrix.col == 1) {
+                                       // Column vector * column vector, transpose first vector
+                                       *self = self_matrix.transpose().mul(other_matrix)(0, 0);
+                               } else {
+                                       // Column vector * row vector, swap factors
+                                       *self = other_matrix.mul(self_matrix)(0, 0);
+                               }
+                       } else {
+                               if (other_matrix.col == 1) {
+                                       // Row vector * column vector, perfect
+                                       *self = self_matrix.mul(other_matrix)(0, 0);
+                               } else {
+                                       // Row vector * row vector, transpose second vector
+                                       *self = self_matrix.mul(other_matrix.transpose())(0, 0);
+                               }
+                       }
+                       *other = _ex1;
+                       return true;
+
+               } else { // vector * matrix
+
+                       // B_i * A_ij = (B*A)_j (B is row vector)
+                       if (is_dummy_pair(self->op(1), other->op(1))) {
+                               if (self_matrix.row == 1)
+                                       *self = indexed(self_matrix.mul(other_matrix), other->op(2));
+                               else
+                                       *self = indexed(self_matrix.transpose().mul(other_matrix), other->op(2));
+                               *other = _ex1;
+                               return true;
+                       }
+
+                       // B_j * A_ij = (A*B)_i (B is column vector)
+                       if (is_dummy_pair(self->op(1), other->op(2))) {
+                               if (self_matrix.col == 1)
+                                       *self = indexed(other_matrix.mul(self_matrix), other->op(1));
+                               else
+                                       *self = indexed(other_matrix.mul(self_matrix.transpose()), other->op(1));
+                               *other = _ex1;
+                               return true;
+                       }
+               }
+
+       } else if (other->nops() == 3) { // matrix * matrix
+
+               // A_ij * B_jk = (A*B)_ik
+               if (is_dummy_pair(self->op(2), other->op(1))) {
+                       *self = indexed(self_matrix.mul(other_matrix), self->op(1), other->op(2));
+                       *other = _ex1;
+                       return true;
+               }
+
+               // A_ij * B_kj = (A*Btrans)_ik
+               if (is_dummy_pair(self->op(2), other->op(2))) {
+                       *self = indexed(self_matrix.mul(other_matrix.transpose()), self->op(1), other->op(1));
+                       *other = _ex1;
+                       return true;
+               }
+
+               // A_ji * B_jk = (Atrans*B)_ik
+               if (is_dummy_pair(self->op(1), other->op(1))) {
+                       *self = indexed(self_matrix.transpose().mul(other_matrix), self->op(2), other->op(2));
+                       *other = _ex1;
+                       return true;
+               }
+
+               // A_ji * B_kj = (B*A)_ki
+               if (is_dummy_pair(self->op(1), other->op(2))) {
+                       *self = indexed(other_matrix.mul(self_matrix), other->op(1), self->op(2));
+                       *other = _ex1;
+                       return true;
+               }
+       }
+
+       return false;
+}
+
+
 //////////
 // non-virtual functions in this class
 //////////
@@ -334,13 +510,13 @@ int matrix::compare_same_type(const basic & other) const
 matrix matrix::add(const matrix & other) const
 {
        if (col != other.col || row != other.row)
-               throw (std::logic_error("matrix::add(): incompatible matrices"));
+               throw std::logic_error("matrix::add(): incompatible matrices");
        
        exvector sum(this->m);
-       exvector::iterator i;
-       exvector::const_iterator ci;
-       for (i=sum.begin(), ci=other.m.begin(); i!=sum.end(); ++i, ++ci)
-               (*i) += (*ci);
+       exvector::iterator i = sum.begin(), end = sum.end();
+       exvector::const_iterator ci = other.m.begin();
+       while (i != end)
+               *i++ += *ci++;
        
        return matrix(row,col,sum);
 }
@@ -352,13 +528,13 @@ matrix matrix::add(const matrix & other) const
 matrix matrix::sub(const matrix & other) const
 {
        if (col != other.col || row != other.row)
-               throw (std::logic_error("matrix::sub(): incompatible matrices"));
+               throw std::logic_error("matrix::sub(): incompatible matrices");
        
        exvector dif(this->m);
-       exvector::iterator i;
-       exvector::const_iterator ci;
-       for (i=dif.begin(), ci=other.m.begin(); i!=dif.end(); ++i, ++ci)
-               (*i) -= (*ci);
+       exvector::iterator i = dif.begin(), end = dif.end();
+       exvector::const_iterator ci = other.m.begin();
+       while (i != end)
+               *i++ -= *ci++;
        
        return matrix(row,col,dif);
 }
@@ -370,7 +546,7 @@ matrix matrix::sub(const matrix & other) const
 matrix matrix::mul(const matrix & other) const
 {
        if (this->cols() != other.rows())
-               throw (std::logic_error("matrix::mul(): incompatible matrices"));
+               throw std::logic_error("matrix::mul(): incompatible matrices");
        
        exvector prod(this->rows()*other.cols());
        
@@ -386,7 +562,79 @@ matrix matrix::mul(const matrix & other) const
 }
 
 
-/** operator() to access elements.
+/** Product of matrix and scalar. */
+matrix matrix::mul(const numeric & other) const
+{
+       exvector prod(row * col);
+
+       for (unsigned r=0; r<row; ++r)
+               for (unsigned c=0; c<col; ++c)
+                       prod[r*col+c] = m[r*col+c] * other;
+
+       return matrix(row, col, prod);
+}
+
+
+/** Product of matrix and scalar expression. */
+matrix matrix::mul_scalar(const ex & other) const
+{
+       if (other.return_type() != return_types::commutative)
+               throw std::runtime_error("matrix::mul_scalar(): non-commutative scalar");
+
+       exvector prod(row * col);
+
+       for (unsigned r=0; r<row; ++r)
+               for (unsigned c=0; c<col; ++c)
+                       prod[r*col+c] = m[r*col+c] * other;
+
+       return matrix(row, col, prod);
+}
+
+
+/** Power of a matrix.  Currently handles integer exponents only. */
+matrix matrix::pow(const ex & expn) const
+{
+       if (col!=row)
+               throw (std::logic_error("matrix::pow(): matrix not square"));
+       
+       if (is_exactly_a<numeric>(expn)) {
+               // Integer cases are computed by successive multiplication, using the
+               // obvious shortcut of storing temporaries, like A^4 == (A*A)*(A*A).
+               if (expn.info(info_flags::integer)) {
+                       numeric b = ex_to<numeric>(expn);
+                       matrix A(row,col);
+                       if (expn.info(info_flags::negative)) {
+                               b *= -1;
+                               A = this->inverse();
+                       } else {
+                               A = *this;
+                       }
+                       matrix C(row,col);
+                       for (unsigned r=0; r<row; ++r)
+                               C(r,r) = _ex1;
+                       if (b.is_zero())
+                               return C;
+                       // This loop computes the representation of b in base 2 from right
+                       // to left and multiplies the factors whenever needed.  Note
+                       // that this is not entirely optimal but close to optimal and
+                       // "better" algorithms are much harder to implement.  (See Knuth,
+                       // TAoCP2, section "Evaluation of Powers" for a good discussion.)
+                       while (b!=_num1) {
+                               if (b.is_odd()) {
+                                       C = C.mul(A);
+                                       --b;
+                               }
+                               b /= _num2;  // still integer.
+                               A = A.mul(A);
+                       }
+                       return A.mul(C);
+               }
+       }
+       throw (std::runtime_error("matrix::pow(): don't know how to handle exponent"));
+}
+
+
+/** operator() to access elements for reading.
  *
  *  @param ro row of element
  *  @param co column of element
@@ -400,23 +648,24 @@ const ex & matrix::operator() (unsigned ro, unsigned co) const
 }
 
 
-/** Set individual elements manually.
+/** operator() to access elements for writing.
  *
+ *  @param ro row of element
+ *  @param co column of element
  *  @exception range_error (index out of range) */
-matrix & matrix::set(unsigned ro, unsigned co, ex value)
+ex & matrix::operator() (unsigned ro, unsigned co)
 {
        if (ro>=row || co>=col)
-               throw (std::range_error("matrix::set(): index out of range"));
-    
+               throw (std::range_error("matrix::operator(): index out of range"));
+
        ensure_if_modifiable();
-       m[ro*col+co] = value;
-       return *this;
+       return m[ro*col+co];
 }
 
 
 /** Transposed of an m x n matrix, producing a new n x m matrix object that
  *  represents the transposed. */
-matrix matrix::transpose(void) const
+matrix matrix::transpose() const
 {
        exvector trans(this->cols()*this->rows());
        
@@ -427,7 +676,6 @@ matrix matrix::transpose(void) const
        return matrix(this->cols(),this->rows(),trans);
 }
 
-
 /** Determinant of square matrix.  This routine doesn't actually calculate the
  *  determinant, it only implements some heuristics about which algorithm to
  *  run.  If all the elements of the matrix are elements of an integral domain
@@ -452,9 +700,10 @@ ex matrix::determinant(unsigned algo) const
        bool numeric_flag = true;
        bool normal_flag = false;
        unsigned sparse_count = 0;  // counts non-zero elements
-       for (exvector::const_iterator r=m.begin(); r!=m.end(); ++r) {
-               lst srl;  // symbol replacement list
-               ex rtest = (*r).to_rational(srl);
+       exvector::const_iterator r = m.begin(), rend = m.end();
+       while (r != rend) {
+               exmap srl;  // symbol replacement list
+               ex rtest = r->to_rational(srl);
                if (!rtest.is_zero())
                        ++sparse_count;
                if (!rtest.info(info_flags::numeric))
@@ -462,6 +711,7 @@ ex matrix::determinant(unsigned algo) const
                if (!rtest.info(info_flags::crational_polynomial) &&
                         rtest.info(info_flags::rational_function))
                        normal_flag = true;
+               ++r;
        }
        
        // Here is the heuristics in case this routine has to decide:
@@ -514,7 +764,7 @@ ex matrix::determinant(unsigned algo) const
                        int sign;
                        sign = tmp.division_free_elimination(true);
                        if (sign==0)
-                               return _ex0();
+                               return _ex0;
                        ex det = tmp.m[row*col-1];
                        // factor out accumulated bogus slag
                        for (unsigned d=0; d<row-2; ++d)
@@ -526,10 +776,13 @@ ex matrix::determinant(unsigned algo) const
                default: {
                        // This is the minor expansion scheme.  We always develop such
                        // that the smallest minors (i.e, the trivial 1x1 ones) are on the
-                       // rightmost column.  For this to be efficient it turns out that
-                       // the emptiest columns (i.e. the ones with most zeros) should be
-                       // the ones on the right hand side.  Therefore we presort the
-                       // columns of the matrix:
+                       // rightmost column.  For this to be efficient, empirical tests
+                       // have shown that the emptiest columns (i.e. the ones with most
+                       // zeros) should be the ones on the right hand side -- although
+                       // this might seem counter-intuitive (and in contradiction to some
+                       // literature like the FORM manual).  Please go ahead and test it
+                       // if you don't believe me!  Therefore we presort the columns of
+                       // the matrix:
                        typedef std::pair<unsigned,unsigned> uintpair;
                        std::vector<uintpair> c_zeros;  // number of zeros in column
                        for (unsigned c=0; c<col; ++c) {
@@ -539,14 +792,15 @@ ex matrix::determinant(unsigned algo) const
                                                ++acc;
                                c_zeros.push_back(uintpair(acc,c));
                        }
-                       sort(c_zeros.begin(),c_zeros.end());
+                       std::sort(c_zeros.begin(),c_zeros.end());
                        std::vector<unsigned> pre_sort;
-                       for (std::vector<uintpair>::iterator i=c_zeros.begin(); i!=c_zeros.end(); ++i)
+                       for (std::vector<uintpair>::const_iterator i=c_zeros.begin(); i!=c_zeros.end(); ++i)
                                pre_sort.push_back(i->second);
-                       int sign = permutation_sign(pre_sort);
+                       std::vector<unsigned> pre_sort_test(pre_sort); // permutation_sign() modifies the vector so we make a copy here
+                       int sign = permutation_sign(pre_sort_test.begin(), pre_sort_test.end());
                        exvector result(row*col);  // represents sorted matrix
                        unsigned c = 0;
-                       for (std::vector<unsigned>::iterator i=pre_sort.begin();
+                       for (std::vector<unsigned>::const_iterator i=pre_sort.begin();
                                 i!=pre_sort.end();
                                 ++i,++c) {
                                for (unsigned r=0; r<row; ++r)
@@ -568,7 +822,7 @@ ex matrix::determinant(unsigned algo) const
  *
  *  @return    the sum of diagonal elements
  *  @exception logic_error (matrix not square) */
-ex matrix::trace(void) const
+ex matrix::trace() const
 {
        if (row != col)
                throw (std::logic_error("matrix::trace(): matrix not square"));
@@ -596,43 +850,47 @@ ex matrix::trace(void) const
  *  @return    characteristic polynomial as new expression
  *  @exception logic_error (matrix not square)
  *  @see       matrix::determinant() */
-ex matrix::charpoly(const symbol & lambda) const
+ex matrix::charpoly(const ex & lambda) const
 {
        if (row != col)
                throw (std::logic_error("matrix::charpoly(): matrix not square"));
        
        bool numeric_flag = true;
-       for (exvector::const_iterator r=m.begin(); r!=m.end(); ++r) {
-               if (!(*r).info(info_flags::numeric)) {
+       exvector::const_iterator r = m.begin(), rend = m.end();
+       while (r!=rend && numeric_flag==true) {
+               if (!r->info(info_flags::numeric))
                        numeric_flag = false;
-               }
+               ++r;
        }
        
        // The pure numeric case is traditionally rather common.  Hence, it is
        // trapped and we use Leverrier's algorithm which goes as row^3 for
        // every coefficient.  The expensive part is the matrix multiplication.
        if (numeric_flag) {
+
                matrix B(*this);
                ex c = B.trace();
-               ex poly = power(lambda,row)-c*power(lambda,row-1);
+               ex poly = power(lambda, row) - c*power(lambda, row-1);
                for (unsigned i=1; i<row; ++i) {
                        for (unsigned j=0; j<row; ++j)
                                B.m[j*col+j] -= c;
                        B = this->mul(B);
-                       c = B.trace()/ex(i+1);
-                       poly -= c*power(lambda,row-i-1);
+                       c = B.trace() / ex(i+1);
+                       poly -= c*power(lambda, row-i-1);
                }
                if (row%2)
                        return -poly;
                else
                        return poly;
-       }
+
+       } else {
        
-       matrix M(*this);
-       for (unsigned r=0; r<col; ++r)
-               M.m[r*col+r] -= lambda;
+               matrix M(*this);
+               for (unsigned r=0; r<col; ++r)
+                       M.m[r*col+r] -= lambda;
        
-       return M.determinant().collect(lambda);
+               return M.determinant().collect(lambda);
+       }
 }
 
 
@@ -641,52 +899,37 @@ ex matrix::charpoly(const symbol & lambda) const
  *  @return    the inverted matrix
  *  @exception logic_error (matrix not square)
  *  @exception runtime_error (singular matrix) */
-matrix matrix::inverse(void) const
+matrix matrix::inverse() const
 {
        if (row != col)
                throw (std::logic_error("matrix::inverse(): matrix not square"));
        
-       // NOTE: the Gauss-Jordan elimination used here can in principle be
-       // replaced this by two clever calls to gauss_elimination() and some to
-       // transpose().  Wouldn't be more efficient (maybe less?), just more
-       // orthogonal.
-       matrix tmp(row,col);
-       // set tmp to the unit matrix
-       for (unsigned i=0; i<col; ++i)
-               tmp.m[i*col+i] = _ex1();
+       // This routine actually doesn't do anything fancy at all.  We compute the
+       // inverse of the matrix A by solving the system A * A^{-1} == Id.
        
-       // create a copy of this matrix
-       matrix cpy(*this);
-       for (unsigned r1=0; r1<row; ++r1) {
-               int indx = cpy.pivot(r1, r1);
-               if (indx == -1) {
+       // First populate the identity matrix supposed to become the right hand side.
+       matrix identity(row,col);
+       for (unsigned i=0; i<row; ++i)
+               identity(i,i) = _ex1;
+       
+       // Populate a dummy matrix of variables, just because of compatibility with
+       // matrix::solve() which wants this (for compatibility with under-determined
+       // systems of equations).
+       matrix vars(row,col);
+       for (unsigned r=0; r<row; ++r)
+               for (unsigned c=0; c<col; ++c)
+                       vars(r,c) = symbol();
+       
+       matrix sol(row,col);
+       try {
+               sol = this->solve(vars,identity);
+       } catch (const std::runtime_error & e) {
+           if (e.what()==std::string("matrix::solve(): inconsistent linear system"))
                        throw (std::runtime_error("matrix::inverse(): singular matrix"));
-               }
-               if (indx != 0) {  // swap rows r and indx of matrix tmp
-                       for (unsigned i=0; i<col; ++i)
-                               tmp.m[r1*col+i].swap(tmp.m[indx*col+i]);
-               }
-               ex a1 = cpy.m[r1*col+r1];
-               for (unsigned c=0; c<col; ++c) {
-                       cpy.m[r1*col+c] /= a1;
-                       tmp.m[r1*col+c] /= a1;
-               }
-               for (unsigned r2=0; r2<row; ++r2) {
-                       if (r2 != r1) {
-                               ex a2 = cpy.m[r2*col+r1];
-                               for (unsigned c=0; c<col; ++c) {
-                                       cpy.m[r2*col+c] -= a2 * cpy.m[r1*col+c];
-                                       if (!cpy.m[r2*col+c].info(info_flags::numeric))
-                                               cpy.m[r2*col+c] = cpy.m[r2*col+c].normal();
-                                       tmp.m[r2*col+c] -= a2 * tmp.m[r1*col+c];
-                                       if (!tmp.m[r2*col+c].info(info_flags::numeric))
-                                               tmp.m[r2*col+c] = tmp.m[r2*col+c].normal();
-                               }
-                       }
-               }
+               else
+                       throw;
        }
-       
-       return tmp;
+       return sol;
 }
 
 
@@ -695,6 +938,7 @@ matrix matrix::inverse(void) const
  *
  *  @param vars n x p matrix, all elements must be symbols 
  *  @param rhs m x p matrix
+ *  @param algo selects the solving algorithm
  *  @return n x p solution matrix
  *  @exception logic_error (incompatible matrices)
  *  @exception invalid_argument (1st argument must be matrix of symbols)
@@ -727,9 +971,11 @@ matrix matrix::solve(const matrix & vars,
        
        // Gather some statistical information about the augmented matrix:
        bool numeric_flag = true;
-       for (exvector::const_iterator r=aug.m.begin(); r!=aug.m.end(); ++r) {
-               if (!(*r).info(info_flags::numeric))
+       exvector::const_iterator r = aug.m.begin(), rend = aug.m.end();
+       while (r!=rend && numeric_flag==true) {
+               if (!r->info(info_flags::numeric))
                        numeric_flag = false;
+               ++r;
        }
        
        // Here is the heuristics in case this routine has to decide:
@@ -749,8 +995,10 @@ matrix matrix::solve(const matrix & vars,
        switch(algo) {
                case solve_algo::gauss:
                        aug.gauss_elimination();
+                       break;
                case solve_algo::divfree:
                        aug.division_free_elimination();
+                       break;
                case solve_algo::bareiss:
                default:
                        aug.fraction_free_elimination();
@@ -773,19 +1021,18 @@ matrix matrix::solve(const matrix & vars,
                                // assign solutions for vars between fnz+1 and
                                // last_assigned_sol-1: free parameters
                                for (unsigned c=fnz; c<last_assigned_sol-1; ++c)
-                                       sol.set(c,co,vars.m[c*p+co]);
+                                       sol(c,co) = vars.m[c*p+co];
                                ex e = aug.m[r*(n+p)+n+co];
                                for (unsigned c=fnz; c<n; ++c)
                                        e -= aug.m[r*(n+p)+c]*sol.m[c*p+co];
-                               sol.set(fnz-1,co,
-                                               (e/(aug.m[r*(n+p)+(fnz-1)])).normal());
+                               sol(fnz-1,co) = (e/(aug.m[r*(n+p)+(fnz-1)])).normal();
                                last_assigned_sol = fnz;
                        }
                }
                // assign solutions for vars between 1 and
                // last_assigned_sol-1: free parameters
                for (unsigned ro=0; ro<last_assigned_sol-1; ++ro)
-                       sol.set(ro,co,vars(ro,co));
+                       sol(ro,co) = vars(ro,co);
        }
        
        return sol;
@@ -804,7 +1051,7 @@ matrix matrix::solve(const matrix & vars,
  *
  *  @return the determinant as a new expression (in expanded form)
  *  @see matrix::determinant() */
-ex matrix::determinant_minor(void) const
+ex matrix::determinant_minor() const
 {
        // for small matrices the algorithm does not make any sense:
        const unsigned n = this->cols();
@@ -829,9 +1076,9 @@ ex matrix::determinant_minor(void) const
        //     for (unsigned r=0; r<minorM.rows(); ++r) {
        //         for (unsigned c=0; c<minorM.cols(); ++c) {
        //             if (r<r1)
-       //                 minorM.set(r,c,m[r*col+c+1]);
+       //                 minorM(r,c) = m[r*col+c+1];
        //             else
-       //                 minorM.set(r,c,m[(r+1)*col+c+1]);
+       //                 minorM(r,c) = m[(r+1)*col+c+1];
        //         }
        //     }
        //     // recurse down and care for sign:
@@ -875,7 +1122,7 @@ ex matrix::determinant_minor(void) const
                        Pkey.push_back(i);
                unsigned fc = 0;  // controls logic for our strange flipper counter
                do {
-                       det = _ex0();
+                       det = _ex0;
                        for (unsigned r=0; r<n-c; ++r) {
                                // maybe there is nothing to do?
                                if (m[Pkey[r]*n+c].is_zero())
@@ -902,7 +1149,7 @@ ex matrix::determinant_minor(void) const
                                if (Pkey[fc-1]<fc+c)
                                        break;
                        }
-                       if (fc<n-c)
+                       if (fc<n-c && fc>0)
                                for (unsigned j=fc; j<n-c; ++j)
                                        Pkey[j] = Pkey[j-1]+1;
                } while(fc);
@@ -944,20 +1191,23 @@ int matrix::gauss_elimination(const bool det)
                        if (indx > 0)
                                sign = -sign;
                        for (unsigned r2=r0+1; r2<m; ++r2) {
-                               ex piv = this->m[r2*n+r1] / this->m[r0*n+r1];
-                               for (unsigned c=r1+1; c<n; ++c) {
-                                       this->m[r2*n+c] -= piv * this->m[r0*n+c];
-                                       if (!this->m[r2*n+c].info(info_flags::numeric))
-                                               this->m[r2*n+c] = this->m[r2*n+c].normal();
+                               if (!this->m[r2*n+r1].is_zero()) {
+                                       // yes, there is something to do in this row
+                                       ex piv = this->m[r2*n+r1] / this->m[r0*n+r1];
+                                       for (unsigned c=r1+1; c<n; ++c) {
+                                               this->m[r2*n+c] -= piv * this->m[r0*n+c];
+                                               if (!this->m[r2*n+c].info(info_flags::numeric))
+                                                       this->m[r2*n+c] = this->m[r2*n+c].normal();
+                                       }
                                }
                                // fill up left hand side with zeros
                                for (unsigned c=0; c<=r1; ++c)
-                                       this->m[r2*n+c] = _ex0();
+                                       this->m[r2*n+c] = _ex0;
                        }
                        if (det) {
                                // save space by deleting no longer needed elements
                                for (unsigned c=r0+1; c<n; ++c)
-                                       this->m[r0*n+c] = _ex0();
+                                       this->m[r0*n+c] = _ex0;
                        }
                        ++r0;
                }
@@ -999,12 +1249,12 @@ int matrix::division_free_elimination(const bool det)
                                        this->m[r2*n+c] = (this->m[r0*n+r1]*this->m[r2*n+c] - this->m[r2*n+r1]*this->m[r0*n+c]).expand();
                                // fill up left hand side with zeros
                                for (unsigned c=0; c<=r1; ++c)
-                                       this->m[r2*n+c] = _ex0();
+                                       this->m[r2*n+c] = _ex0;
                        }
                        if (det) {
                                // save space by deleting no longer needed elements
                                for (unsigned c=r0+1; c<n; ++c)
-                                       this->m[r0*n+c] = _ex0();
+                                       this->m[r0*n+c] = _ex0;
                        }
                        ++r0;
                }
@@ -1034,7 +1284,7 @@ int matrix::fraction_free_elimination(const bool det)
        //
        // Bareiss (fraction-free) elimination in addition divides that element
        // by m[k-1](k-1,k-1) for k>1, where it can be shown by means of the
-       // Sylvester determinant that this really divides m[k+1](r,c).
+       // Sylvester identity that this really divides m[k+1](r,c).
        //
        // We also allow rational functions where the original prove still holds.
        // However, we must care for numerator and denominator separately and
@@ -1071,14 +1321,14 @@ int matrix::fraction_free_elimination(const bool det)
        // makes things more complicated than they need to be.
        matrix tmp_n(*this);
        matrix tmp_d(m,n);  // for denominators, if needed
-       lst srl;  // symbol replacement list
-       exvector::iterator it = this->m.begin();
-       exvector::iterator tmp_n_it = tmp_n.m.begin();
-       exvector::iterator tmp_d_it = tmp_d.m.begin();
-       for (; it!= this->m.end(); ++it, ++tmp_n_it, ++tmp_d_it) {
-               (*tmp_n_it) = (*it).normal().to_rational(srl);
-               (*tmp_d_it) = (*tmp_n_it).denom();
-               (*tmp_n_it) = (*tmp_n_it).numer();
+       exmap srl;  // symbol replacement list
+       exvector::const_iterator cit = this->m.begin(), citend = this->m.end();
+       exvector::iterator tmp_n_it = tmp_n.m.begin(), tmp_d_it = tmp_d.m.begin();
+       while (cit != citend) {
+               ex nd = cit->normal().to_rational(srl).numer_denom();
+               ++cit;
+               *tmp_n_it++ = nd.op(0);
+               *tmp_d_it++ = nd.op(1);
        }
        
        unsigned r0 = 0;
@@ -1112,7 +1362,7 @@ int matrix::fraction_free_elimination(const bool det)
                                }
                                // fill up left hand side with zeros
                                for (unsigned c=0; c<=r1; ++c)
-                                       tmp_n.m[r2*n+c] = _ex0();
+                                       tmp_n.m[r2*n+c] = _ex0;
                        }
                        if ((r1<n-1)&&(r0<m-1)) {
                                // compute next iteration's divisor
@@ -1121,8 +1371,8 @@ int matrix::fraction_free_elimination(const bool det)
                                if (det) {
                                        // save space by deleting no longer needed elements
                                        for (unsigned c=0; c<n; ++c) {
-                                               tmp_n.m[r0*n+c] = _ex0();
-                                               tmp_d.m[r0*n+c] = _ex1();
+                                               tmp_n.m[r0*n+c] = _ex0;
+                                               tmp_d.m[r0*n+c] = _ex1;
                                        }
                                }
                        }
@@ -1130,11 +1380,11 @@ int matrix::fraction_free_elimination(const bool det)
                }
        }
        // repopulate *this matrix:
-       it = this->m.begin();
+       exvector::iterator it = this->m.begin(), itend = this->m.end();
        tmp_n_it = tmp_n.m.begin();
        tmp_d_it = tmp_d.m.begin();
-       for (; it!= this->m.end(); ++it, ++tmp_n_it, ++tmp_d_it)
-               (*it) = ((*tmp_n_it)/(*tmp_d_it)).subs(srl);
+       while (it != itend)
+               *it++ = ((*tmp_n_it++)/(*tmp_d_it++)).subs(srl, subs_options::no_pattern);
        
        return sign;
 }
@@ -1162,12 +1412,12 @@ int matrix::pivot(unsigned ro, unsigned co, bool symbolic)
                        ++k;
        } else {
                // search largest element in column co beginning at row ro
-               GINAC_ASSERT(is_ex_of_type(this->m[k*col+co],numeric));
+               GINAC_ASSERT(is_exactly_a<numeric>(this->m[k*col+co]));
                unsigned kmax = k+1;
-               numeric mmax = abs(ex_to_numeric(m[kmax*col+co]));
+               numeric mmax = abs(ex_to<numeric>(m[kmax*col+co]));
                while (kmax<row) {
-                       GINAC_ASSERT(is_ex_of_type(this->m[kmax*col+co],numeric));
-                       numeric tmp = ex_to_numeric(this->m[kmax*col+co]);
+                       GINAC_ASSERT(is_exactly_a<numeric>(this->m[kmax*col+co]));
+                       numeric tmp = ex_to<numeric>(this->m[kmax*col+co]);
                        if (abs(tmp) > mmax) {
                                mmax = tmp;
                                k = kmax;
@@ -1186,41 +1436,99 @@ int matrix::pivot(unsigned ro, unsigned co, bool symbolic)
        // matrix needs pivoting, so swap rows k and ro
        ensure_if_modifiable();
        for (unsigned c=0; c<col; ++c)
-               m[k*col+c].swap(m[ro*col+c]);
+               this->m[k*col+c].swap(this->m[ro*col+c]);
        
        return k;
 }
 
-/** Convert list of lists to matrix. */
-ex lst_to_matrix(const ex &l)
+ex lst_to_matrix(const lst & l)
 {
-       if (!is_ex_of_type(l, lst))
-               throw(std::invalid_argument("argument to lst_to_matrix() must be a lst"));
-       
+       lst::const_iterator itr, itc;
+
        // Find number of rows and columns
-       unsigned rows = l.nops(), cols = 0, i, j;
-       for (i=0; i<rows; i++)
-               if (l.op(i).nops() > cols)
-                       cols = l.op(i).nops();
-       
+       size_t rows = l.nops(), cols = 0;
+       for (itr = l.begin(); itr != l.end(); ++itr) {
+               if (!is_a<lst>(*itr))
+                       throw (std::invalid_argument("lst_to_matrix: argument must be a list of lists"));
+               if (itr->nops() > cols)
+                       cols = itr->nops();
+       }
+
        // Allocate and fill matrix
-       matrix &m = *new matrix(rows, cols);
-       for (i=0; i<rows; i++)
-               for (j=0; j<cols; j++)
-                       if (l.op(i).nops() > j)
-                               m.set(i, j, l.op(i).op(j));
-                       else
-                               m.set(i, j, ex(0));
-       return m;
+       matrix &M = *new matrix(rows, cols);
+       M.setflag(status_flags::dynallocated);
+
+       unsigned i;
+       for (itr = l.begin(), i = 0; itr != l.end(); ++itr, ++i) {
+               unsigned j;
+               for (itc = ex_to<lst>(*itr).begin(), j = 0; itc != ex_to<lst>(*itr).end(); ++itc, ++j)
+                       M(i, j) = *itc;
+       }
+
+       return M;
 }
 
-//////////
-// global constants
-//////////
+ex diag_matrix(const lst & l)
+{
+       lst::const_iterator it;
+       size_t dim = l.nops();
+
+       // Allocate and fill matrix
+       matrix &M = *new matrix(dim, dim);
+       M.setflag(status_flags::dynallocated);
+
+       unsigned i;
+       for (it = l.begin(), i = 0; it != l.end(); ++it, ++i)
+               M(i, i) = *it;
+
+       return M;
+}
+
+ex unit_matrix(unsigned r, unsigned c)
+{
+       matrix &Id = *new matrix(r, c);
+       Id.setflag(status_flags::dynallocated);
+       for (unsigned i=0; i<r && i<c; i++)
+               Id(i,i) = _ex1;
+
+       return Id;
+}
+
+ex symbolic_matrix(unsigned r, unsigned c, const std::string & base_name, const std::string & tex_base_name)
+{
+       matrix &M = *new matrix(r, c);
+       M.setflag(status_flags::dynallocated | status_flags::evaluated);
+
+       bool long_format = (r > 10 || c > 10);
+       bool single_row = (r == 1 || c == 1);
+
+       for (unsigned i=0; i<r; i++) {
+               for (unsigned j=0; j<c; j++) {
+                       std::ostringstream s1, s2;
+                       s1 << base_name;
+                       s2 << tex_base_name << "_{";
+                       if (single_row) {
+                               if (c == 1) {
+                                       s1 << i;
+                                       s2 << i << '}';
+                               } else {
+                                       s1 << j;
+                                       s2 << j << '}';
+                               }
+                       } else {
+                               if (long_format) {
+                                       s1 << '_' << i << '_' << j;
+                                       s2 << i << ';' << j << "}";
+                               } else {
+                                       s1 << i << j;
+                                       s2 << i << j << '}';
+                               }
+                       }
+                       M(i, j) = symbol(s1.str(), s2.str());
+               }
+       }
 
-const matrix some_matrix;
-const std::type_info & typeid_matrix = typeid(some_matrix);
+       return M;
+}
 
-#ifndef NO_NAMESPACE_GINAC
 } // namespace GiNaC
-#endif // ndef NO_NAMESPACE_GINAC