Services & Resources / Wolfram Forums / MathGroup Archive

MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

Solved: Factor/Simplify set of complex expressions

  • To: mathgroup at
  • Subject: [mg116677] Solved: Factor/Simplify set of complex expressions
  • From: Enrique Fernández Perdomo <enrique.fernandez.perdomo at>
  • Date: Wed, 23 Feb 2011 06:23:38 -0500 (EST)

Hello all,

Given a function and its derivatives, it is possible to obtain an optimized expression to compute all of them using:

Here it is a synthetic example:
z = 1 - Tanh[(y - B[t] Cos[k (x - c t)])/Sqrt[1 + (k B[t] Sin[k (x - c t)])^2]];
res = Table[D[z, {x, i}, {y, j}], {i, 1, 2}, {j, 1, 2}] // Simplify

Notice that the call to Simplify takes some time depending on the original function, but if not used the resulting optimized expression would be larger. So, you might omit Simplify or use a simpler function, like:
z = b (1 - f[x, y, t]^2);

Thanks to Oliver Ruebenkoenig.

Best regards,

  • Prev by Date: Re: outputting C code
  • Next by Date: Re: Integral with singularities
  • Previous by thread: Re: Rational[a,b] vs Rational[1,2]
  • Next by thread: Re: Solved: Factor/Simplify set of complex expressions