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FastMinors :: recursiveMinors

recursiveMinors -- uses a recursive cofactor algorithm to compute the ideal of minors of a matrix

Synopsis

Description

Given a matrix $M$, this computes the ideal of determinants of size $n \times n$ submatrices. The recursiveMinors function uses a recursive strategy, keeping track of the smaller minors computed so far, unlike the built-in Cofactor strategy for minors

i1 : R = QQ[x,y];
i2 : M = random(R^{5,5,5,5,5,5}, R^7);

             6       7
o2 : Matrix R  <--- R
i3 : time I2 = recursiveMinors(4, M, Threads=>0);
     -- used 0.725873 seconds

o3 : Ideal of R
i4 : time I1 = minors(4, M, Strategy=>Cofactor);
     -- used 2.51926 seconds

o4 : Ideal of R
i5 : I1 == I2

o5 = true

See also

Ways to use recursiveMinors :

For the programmer

The object recursiveMinors is a method function with options.