Symbolic Jacobian
in [Matlab]
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From: Sander on 28 Jul 2010 07:21 I have a simple question with possibly a difficult answer. The new symbolic toolbox of matlab seems very powerful. One of the uses is to differentiate functions. Subsequently it should be possible to use the differentiated functions as normal numerical functions, but my question is how. I want to use these equations to build up a Jacobian matrix. So I'm searching for example: f=x^2 symbolically: df/dx=2*x go back to numeric (HOW?!) J=2*x Admittedly, the example is bad, but I hope the idea is clear. If someone could halp me out, I'll be very happy :-)
From: Sander on 28 Jul 2010 07:34 By the way, I know that you can make the symbolic Jacobian by simply using the function 'jacobian', but still need to know how to use the symbolic evaluation as 'text' to use as a 'numerical jacobian'. Thanks in advance, Sander
From: Alan Weiss on 28 Jul 2010 08:19 On 7/28/2010 7:34 AM, Sander wrote: > By the way, I know that you can make the symbolic Jacobian by simply > using the function 'jacobian', but still need to know how to use the > symbolic evaluation as 'text' to use as a 'numerical jacobian'. > > Thanks in advance, > Sander Take a look at some examples in Optimization Toolbox documentation: http://www.mathworks.com/access/helpdesk/help/toolbox/optim/ug/brn4nh7.html#brv_i_1 http://www.mathworks.com/products/optimization/demos.html?file=/products/demos/shipping/optim/symbolic_optim_demo.html Alan Weiss MATLAB mathematical toolbox documentation
From: Steven_Lord on 28 Jul 2010 09:18 "Sander " <s.a.tromp(a)tudelft.nl> wrote in message news:i2p3r0$3vb$1(a)fred.mathworks.com... > I have a simple question with possibly a difficult answer. > > The new symbolic toolbox of matlab seems very powerful. One of the uses is > to differentiate functions. Subsequently it should be possible to use the > differentiated functions as normal numerical functions, but my question is > how. I want to use these equations to build up a Jacobian matrix. > > So I'm searching for example: > f=x^2 symbolically: df/dx=2*x > go back to numeric (HOW?!) > J=2*x > > Admittedly, the example is bad, but I hope the idea is clear. If someone > could halp me out, I'll be very happy :-) Use MATLABFUNCTION. -- Steve Lord slord(a)mathworks.com comp.soft-sys.matlab (CSSM) FAQ: http://matlabwiki.mathworks.com/MATLAB_FAQ To contact Technical Support use the Contact Us link on http://www.mathworks.com
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