// Most matrix library routines replace the contents of the matrix object.   That is:
// X.sub(Y) will replace X with X - Y.
//
// Only the following routines allocate a new matrix leaving the original
// matrix untouched.  For these routines you need to assign the result
// to a new matrix: X = Y.dot(Z)
// or print them out: Y.dot(Z).print()
// 
// argMinRow()
// cartesianRow(double (*f)(int size, double *x, double *y), Matrix &other)
// cov()
// cov(Matrix &other)
// dot(const Matrix &other)
// dotT(const Matrix &other)
// Tdot(const Matrix &other)
// eigenSystem()  // danger this replaces the object AND returns a new matrix
// extract(int minr, int minc, int sizer, int sizec)
// meanVec()
// minRow()
// pickRows(int match, const Matrix &list, int &num)
// stddevVec()
// transpose()
//