Gram-Schmidt orthonormalization

The gramschmidt command uses the Gram-Schmidt procedure to find an orthonormal set of vectors with the same span as a given set.

gramschmidt takes one or two arguments:
- A, a matrix viewed as a list of row vectors or a list of elements that is a basis of a vector subspace.
- f, a function that defines a scalar product on this vector space. If A is a matrix, then this is optional, and by default will be the standard scalar product.
gramschmidt(A) or gramschmidt(L,f) returns an orthonormal basis for this scalar product.

normal(gramschmidt([[1,1,1],[0,0,1],[0,1,0]]))

or:

normal(gramschmidt([[1,1,1],[0,0,1],[0,1,0]],dot))

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Define a scalar product on the vector space of polynomials by P· Q=∫₋₁¹P(x) Q(x) dx. Then:

p_scal(p,q):=integrate(p*q,x,-1,1):; gramschmidt([1,1+x],p_scal)

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