Symbolic Math Toolbox

Obsolete Functions

This version maintains some compatibility with version 1. For example, the following obsolete functions continue to be available in version 2, though you should avoid using them as future releases may not include them.

Function	Description
determ	Symbolic matrix determinant
linsolve	Solve simultaneous linear equations
eigensys	Symbolic eigenvalues and eigenvectors
singvals	Symbolic singular values and singular vectors
numeric	Convert symbolic matrix to numeric form
symop	Symbolic operations
symadd	Add symbolic expressions
symsub	Subtract symbolic expressions
symmul	Multiply symbolic expressions
symdiv	Divide symbolic expressions
sympow	Power of symbolic expression
eval	Evaluate a symbolic expression

In version 1, these functions accepted strings as arguments and returned strings as results. In version 2, they accept either strings or symbolic objects as input arguments and produce symbolic objects as results. Version 2 provides overloaded MATLAB operators or new functions that you can use to replace most of these functions in your existing code.

For example, the version 1 statements

• f = '1/(5+4*cos(x))'
  g = int(int(diff(f,2)))
  e = symsub(f,g)
  simple(e)
  

continue to work in version 2. However, with version 2, the preferred approach is

• syms x
  f = 1/(5+4*cos(x))
  g = int(int(diff(f,2)))
  e = f - g
  simple(e)
  

The version 1 statements

• H = sym(hilb(3))
  I = sym(eye(3))
  X = linsolve(H,I)
  t = sym(0)
  for j = 1:3
     t = symadd(t,sym(X,j,j))
  end
  t
  

continue to work in version 2. However, the preferred approach is

• H = sym(hilb(3))
  I = eye(3)
  X = H\I
  t = sum(diag(X))
  

You can no longer use the sym function in this way:

• M = sym(3,3,'1/(i+j-t)')
  

Instead, you must change the code to something like this:

• syms t
  [J,I] = meshgrid(1:3)
  M = 1./(I+J-t)
  

As in version 1, you can supply diff, int, solve, and dsolve with string arguments in version 2. In version 2, however, these functions return symbolic objects instead of strings.

For some computations, the new release of Maple produces results in a different format.

For example, with version 1, the statement

• [x,y] = solve('x^2 + 2*x*y + y^2 = 4', 'x^3 + 4*y^3 = 1')
  

produces

• x =
        [   -RootOf(_Z^3-2*_Z^2-4*_Z-3)-2]
        [-RootOf(3*_Z^3+6*_Z^2-12*_Z+7)+2]
     
  y =
        [   RootOf(_Z^3-2*_Z^2-4*_Z-3)]
        [RootOf(3*_Z^3+6*_Z^2-12*_Z+7)]
  

The same statement works in version 2, but produces results with the RootOf expressions expanded to exhibit the multiple solutions.

Compatibility Guide