/**
*Overloading the '*' operator. Only works when matrix a's columns are equal to matrix b's
*rows, otherwise there is a size error.
*Returns a new matrix equal to a * b
*
*/
SMatrix operator*(const SMatrix& a, const SMatrix& b) throw(MatrixError) {
if(a.cols() != b.rows()) { //Check whether a's columns are equal to b's rows
throw MatrixError("Matrix size error"); //if not throw size error
}
SMatrix c(a.rows(),b.cols()); //dimensions of new matrix
for(auto it = a.ridx_.cbegin();it != a.ridx_.cend();++it) { //Loop through a's rows
int row = it->first;
int nElements = it->second.first + it->second.second;
for(SMatrix::size_type i = 0; i < b.cols(); ++i) { //Loop through b's columns
int col = i;
int val = 0;
for(int pos = it->second.first; pos < nElements; ++pos) { //Loop through a's columns
val += a.vals_[pos] * b(a.cidx_[pos],i); //adding the multiplications to
} //val
if(val != 0) {
c.setVal(row,col,val);
}
}
}
return c;
}
/**
*Overloading the '!=' operator.
*Returns a bool value whether the matrices are not equal
*
*/
bool operator!=(const SMatrix& a, const SMatrix& b) {
bool notEqual = false;
if(a.rows() != b.rows() || a.cols() != b.cols()) { //If the matrices have different
notEqual = true; //dimensions
} else {
b.begin();
for(a.begin(); !a.end() && !notEqual; a.next()) { //Compare all values of a to b until
if(a.value() != b.value()) { //not matching values are
notEqual = true; //found
}
b.next();
}
}
return notEqual;
}
/**
*Overloading the '==' operator.
*Returns a bool value whether the matrices are equal
*
*/
bool operator==(const SMatrix& a, const SMatrix& b) {
bool equal = true;
if(a.rows() != b.rows() || a.cols() != b.cols()) { //If the matrices do not have the
equal = false; //same dimensions
} else {
b.begin();
for(a.begin(); !a.end(); a.next()) { //compare all the values of a to b
if(a.value() != b.value()) {
equal = false;
}
b.next();
}
}
return equal;
}
/**
*Overloading the '-' operator. Only works when both matrices have equal dimensions
*Returns a new matrix equal to a - b
*
*/
SMatrix operator-(const SMatrix& a, const SMatrix& b) throw(MatrixError) {
if(a.cols() != b.cols() || a.rows() != b.rows()) { //Check whether or not dimensions are equal
throw MatrixError("Matrix size error"); //if not throw size error
}
SMatrix c(a.rows(),a.cols()); //dimensions of new matrix
b.begin();
for(a.begin(); !a.end(); a.next()) { //Loop through all values of a and b, and subtract
int val = a.value() - b.value();
c.setVal(a.rowPointer_,a.colPointer_,val); //add new subtraction to new matrix
b.next();
}
return c;
}
/**
*Transpose method, that transposes a matrix.
*Returns a new matrix equal to the transpose of a.
*/
SMatrix transpose(const SMatrix& a) {
SMatrix c(a.rows(),a.cols());
for(auto it = a.ridx_.cbegin();it != a.ridx_.cend();++it) { //Loop through a's rows
int row = it->first;
int nElements = it->second.first + it->second.second;
for(int pos = it->second.first; pos < nElements; ++pos) { //Loop through a's columns
c.setVal(a.cidx_[pos],row,a.vals_[pos]); //add value to new matrix
} //with rows and columns swapped
}
return c;
}