Hessian example.

---

Hessian.sm (11 KiB) downloaded 115 time(s).

:d

Check this.

---

It is not a good idea to use smath subscripts in maple. Here I need to think a little bit.

---

Nice bug. This a workaround.

---

I think that this is the better way to work with the Jacobian.

Alvaro.

---

Jacobian.sm (22 KiB) downloaded 118 time(s).

Hello Alvaro,

But what to do if the vector function is defined this way?

[MATH=eng]Φ(X,t):-5*t*mat(el(X,1),el(X,2),2,1)+mat(el(X,2)*el(X,1)^2,el(X,2)^2*el(X,1)^2,2,1)[/MATH]

It will not work until t is a constant (scalar). Take a look at the pictures please.

Regards,
Radovan

---

What doesn´t works is length, so can't include symbolic scalars outside vectors.

Regards.

---

Hello Alvaro,

Actually, that is the point. I think that's the problem of the symbolic engine.
The first one gives the symbolic result

[MATH=eng](-5*t)*mat(el(X,1),el(X,2),2,1)+mat(el(X,2)*el(X,1)^2,el(X,2)^2*el(X,1),2,1)=mat(-5*el(X,1),-5*el(X,2),2,1)*t+mat(el(X,2)*el(X,1)^2,el(X,2)^2*el(X,1),2,1)[/MATH]

and the result is not a vector, therefore length() does not work.
The second one actually give you the vector symbolically

[MATH=eng](-5)*mat(el(X,1)*t,el(X,2)*t,2,1)+mat(el(X,2)*el(X,1)^2,el(X,2)^2*el(X,1),2,1)=mat(el(X,1)*(-5*t+el(X,2)*el(X,1)),el(X,2)*(-5*t+el(X,2)*el(X,1)),2,1)[/MATH]


Maybe the solution would be to say in advance what the variable t was - either scalar, vector or matrix. Something like "assume". If SMath assumed that t was a scalar, it should behave in accordance to that and give you the second correct result.

Regards,
Radovan