Description of fast matrix multiplication algorithm: ⟨4×7×7:147⟩

Algorithm type

3X4Y4Z4+X4Y2Z4+2X2Y5Z2+2X3Y2Z3+4X2Y4Z2+33X2Y2Z2+4X2YZ2+18XY3Z+16XY2Z+64XYZ3X4Y4Z4X4Y2Z42X2Y5Z22X3Y2Z34X2Y4Z233X2Y2Z24X2YZ218XY3Z16XY2Z64XYZ3*X^4*Y^4*Z^4+X^4*Y^2*Z^4+2*X^2*Y^5*Z^2+2*X^3*Y^2*Z^3+4*X^2*Y^4*Z^2+33*X^2*Y^2*Z^2+4*X^2*Y*Z^2+18*X*Y^3*Z+16*X*Y^2*Z+64*X*Y*Z

Algorithm definition

The algorithm ⟨4×7×7:147⟩ could be constructed using the following decomposition:

⟨4×7×7:147⟩ = ⟨2×4×4:26⟩ + ⟨2×4×3:20⟩ + ⟨2×3×4:20⟩ + ⟨2×4×4:26⟩ + ⟨2×3×4:20⟩ + ⟨2×4×3:20⟩ + ⟨2×3×3:15⟩.

This decomposition is defined by the following equality:

TraceMulA_1_1A_1_2A_1_3A_1_4A_1_5A_1_6A_1_7A_2_1A_2_2A_2_3A_2_4A_2_5A_2_6A_2_7A_3_1A_3_2A_3_3A_3_4A_3_5A_3_6A_3_7A_4_1A_4_2A_4_3A_4_4A_4_5A_4_6A_4_7B_1_1B_1_2B_1_3B_1_4B_1_5B_1_6B_1_7B_2_1B_2_2B_2_3B_2_4B_2_5B_2_6B_2_7B_3_1B_3_2B_3_3B_3_4B_3_5B_3_6B_3_7B_4_1B_4_2B_4_3B_4_4B_4_5B_4_6B_4_7B_5_1B_5_2B_5_3B_5_4B_5_5B_5_6B_5_7B_6_1B_6_2B_6_3B_6_4B_6_5B_6_6B_6_7B_7_1B_7_2B_7_3B_7_4B_7_5B_7_6B_7_7C_1_1C_1_2C_1_3C_1_4C_2_1C_2_2C_2_3C_2_4C_3_1C_3_2C_3_3C_3_4C_4_1C_4_2C_4_3C_4_4C_5_1C_5_2C_5_3C_5_4C_6_1C_6_2C_6_3C_6_4C_7_1C_7_2C_7_3C_7_4=TraceMulA_3_2A_1_1+A_3_3A_1_4+A_3_6A_1_5+A_3_7A_4_2A_2_1+A_4_3A_4_6+A_2_4A_2_5+A_4_7B_2_2B_2_3B_2_6B_2_7B_3_2B_1_1+B_3_3B_3_6+B_1_4B_3_7+B_1_5B_6_2B_6_3+B_4_1B_6_6+B_4_4B_6_7+B_4_5B_7_2B_7_3+B_5_1B_7_6+B_5_4B_7_7+B_5_5C_2_3C_2_4C_1_1+C_3_3C_1_2+C_3_4C_4_1+C_6_3C_6_4+C_4_2C_5_1+C_7_3C_5_2+C_7_4+TraceMulA_1_2-A_3_2A_1_3-A_3_3A_1_6-A_3_6A_1_7-A_3_7A_2_2-A_4_2A_2_3-A_4_3-A_4_6+A_2_6A_2_7-A_4_7B_2_1+B_2_3B_2_6+B_2_4B_2_7+B_2_5B_3_1+B_3_3B_3_6+B_3_4B_3_7+B_3_5B_6_3+B_6_1B_6_6+B_6_4B_6_7+B_6_5B_7_3+B_7_1B_7_6+B_7_4B_7_7+B_7_5C_1_1C_1_2C_4_1C_4_2C_5_1C_5_2+TraceMul-A_1_1+A_3_1-A_1_4+A_3_4-A_1_5+A_3_5-A_2_1+A_4_1-A_2_4+A_4_4A_4_5-A_2_5B_1_2B_1_1+B_1_3B_1_6+B_1_4B_1_7+B_1_5B_4_2B_4_1+B_4_3B_4_6+B_4_4B_4_7+B_4_5B_5_2B_5_1+B_5_3B_5_6+B_5_4B_5_7+B_5_5C_2_3C_2_4C_3_3C_3_4C_6_3C_6_4C_7_3C_7_4+TraceMulA_1_2A_1_1+A_1_3A_1_4+A_1_6A_1_5+A_1_7A_2_2A_2_1+A_2_3A_2_4+A_2_6A_2_5+A_2_7B_2_2B_2_3B_2_6B_2_7B_3_2B_3_3B_3_6B_3_7B_6_2B_6_3B_6_6B_6_7B_7_2B_7_3B_7_6B_7_7C_2_1C_2_2-C_1_1+C_3_1C_3_2-C_1_2C_6_1-C_4_1C_6_2-C_4_2C_7_1-C_5_1C_7_2-C_5_2+TraceMulA_1_1A_1_4A_1_5A_2_1A_2_4A_2_5B_1_2-B_3_2B_1_3-B_3_3-B_3_6+B_1_6B_1_7-B_3_7B_4_2-B_6_2B_4_3-B_6_3B_4_6-B_6_6-B_6_7+B_4_7B_5_2-B_7_2B_5_3-B_7_3B_5_6-B_7_6B_5_7-B_7_7C_2_1+C_2_3C_2_2+C_2_4C_3_1+C_3_3C_3_2+C_3_4C_6_1+C_6_3C_6_2+C_6_4C_7_1+C_7_3C_7_2+C_7_4+TraceMulA_3_2A_3_3A_3_6A_3_7A_4_2A_4_3A_4_6A_4_7B_2_1B_2_4B_2_5-B_1_1+B_3_1-B_1_4+B_3_4-B_1_5+B_3_5-B_4_1+B_6_1-B_4_4+B_6_4-B_4_5+B_6_5-B_5_1+B_7_1-B_5_4+B_7_4-B_5_5+B_7_5C_1_1+C_1_3C_1_2+C_1_4C_4_1+C_4_3C_4_2+C_4_4C_5_1+C_5_3C_5_4+C_5_2+TraceMulA_3_1+A_3_3A_3_4+A_3_6A_3_5+A_3_7A_4_1+A_4_3A_4_4+A_4_6A_4_5+A_4_7B_1_1B_1_4B_1_5B_4_1B_4_4B_4_5B_5_1B_5_4B_5_5C_1_3-C_3_3C_1_4-C_3_4C_4_3-C_6_3-C_6_4+C_4_4C_5_3-C_7_3C_5_4-C_7_4TraceMulA_1_1A_1_2A_1_3A_1_4A_1_5A_1_6A_1_7A_2_1A_2_2A_2_3A_2_4A_2_5A_2_6A_2_7A_3_1A_3_2A_3_3A_3_4A_3_5A_3_6A_3_7A_4_1A_4_2A_4_3A_4_4A_4_5A_4_6A_4_7B_1_1B_1_2B_1_3B_1_4B_1_5B_1_6B_1_7B_2_1B_2_2B_2_3B_2_4B_2_5B_2_6B_2_7B_3_1B_3_2B_3_3B_3_4B_3_5B_3_6B_3_7B_4_1B_4_2B_4_3B_4_4B_4_5B_4_6B_4_7B_5_1B_5_2B_5_3B_5_4B_5_5B_5_6B_5_7B_6_1B_6_2B_6_3B_6_4B_6_5B_6_6B_6_7B_7_1B_7_2B_7_3B_7_4B_7_5B_7_6B_7_7C_1_1C_1_2C_1_3C_1_4C_2_1C_2_2C_2_3C_2_4C_3_1C_3_2C_3_3C_3_4C_4_1C_4_2C_4_3C_4_4C_5_1C_5_2C_5_3C_5_4C_6_1C_6_2C_6_3C_6_4C_7_1C_7_2C_7_3C_7_4TraceMulA_3_2A_1_1A_3_3A_1_4A_3_6A_1_5A_3_7A_4_2A_2_1A_4_3A_4_6A_2_4A_2_5A_4_7B_2_2B_2_3B_2_6B_2_7B_3_2B_1_1B_3_3B_3_6B_1_4B_3_7B_1_5B_6_2B_6_3B_4_1B_6_6B_4_4B_6_7B_4_5B_7_2B_7_3B_5_1B_7_6B_5_4B_7_7B_5_5C_2_3C_2_4C_1_1C_3_3C_1_2C_3_4C_4_1C_6_3C_6_4C_4_2C_5_1C_7_3C_5_2C_7_4TraceMulA_1_2A_3_2A_1_3A_3_3A_1_6A_3_6A_1_7A_3_7A_2_2A_4_2A_2_3A_4_3A_4_6A_2_6A_2_7A_4_7B_2_1B_2_3B_2_6B_2_4B_2_7B_2_5B_3_1B_3_3B_3_6B_3_4B_3_7B_3_5B_6_3B_6_1B_6_6B_6_4B_6_7B_6_5B_7_3B_7_1B_7_6B_7_4B_7_7B_7_5C_1_1C_1_2C_4_1C_4_2C_5_1C_5_2TraceMulA_1_1A_3_1A_1_4A_3_4A_1_5A_3_5A_2_1A_4_1A_2_4A_4_4A_4_5A_2_5B_1_2B_1_1B_1_3B_1_6B_1_4B_1_7B_1_5B_4_2B_4_1B_4_3B_4_6B_4_4B_4_7B_4_5B_5_2B_5_1B_5_3B_5_6B_5_4B_5_7B_5_5C_2_3C_2_4C_3_3C_3_4C_6_3C_6_4C_7_3C_7_4TraceMulA_1_2A_1_1A_1_3A_1_4A_1_6A_1_5A_1_7A_2_2A_2_1A_2_3A_2_4A_2_6A_2_5A_2_7B_2_2B_2_3B_2_6B_2_7B_3_2B_3_3B_3_6B_3_7B_6_2B_6_3B_6_6B_6_7B_7_2B_7_3B_7_6B_7_7C_2_1C_2_2C_1_1C_3_1C_3_2C_1_2C_6_1C_4_1C_6_2C_4_2C_7_1C_5_1C_7_2C_5_2TraceMulA_1_1A_1_4A_1_5A_2_1A_2_4A_2_5B_1_2B_3_2B_1_3B_3_3B_3_6B_1_6B_1_7B_3_7B_4_2B_6_2B_4_3B_6_3B_4_6B_6_6B_6_7B_4_7B_5_2B_7_2B_5_3B_7_3B_5_6B_7_6B_5_7B_7_7C_2_1C_2_3C_2_2C_2_4C_3_1C_3_3C_3_2C_3_4C_6_1C_6_3C_6_2C_6_4C_7_1C_7_3C_7_2C_7_4TraceMulA_3_2A_3_3A_3_6A_3_7A_4_2A_4_3A_4_6A_4_7B_2_1B_2_4B_2_5B_1_1B_3_1B_1_4B_3_4B_1_5B_3_5B_4_1B_6_1B_4_4B_6_4B_4_5B_6_5B_5_1B_7_1B_5_4B_7_4B_5_5B_7_5C_1_1C_1_3C_1_2C_1_4C_4_1C_4_3C_4_2C_4_4C_5_1C_5_3C_5_4C_5_2TraceMulA_3_1A_3_3A_3_4A_3_6A_3_5A_3_7A_4_1A_4_3A_4_4A_4_6A_4_5A_4_7B_1_1B_1_4B_1_5B_4_1B_4_4B_4_5B_5_1B_5_4B_5_5C_1_3C_3_3C_1_4C_3_4C_4_3C_6_3C_6_4C_4_4C_5_3C_7_3C_5_4C_7_4Trace(Mul(Matrix(4, 7, [[A_1_1,A_1_2,A_1_3,A_1_4,A_1_5,A_1_6,A_1_7],[A_2_1,A_2_2,A_2_3,A_2_4,A_2_5,A_2_6,A_2_7],[A_3_1,A_3_2,A_3_3,A_3_4,A_3_5,A_3_6,A_3_7],[A_4_1,A_4_2,A_4_3,A_4_4,A_4_5,A_4_6,A_4_7]]),Matrix(7, 7, [[B_1_1,B_1_2,B_1_3,B_1_4,B_1_5,B_1_6,B_1_7],[B_2_1,B_2_2,B_2_3,B_2_4,B_2_5,B_2_6,B_2_7],[B_3_1,B_3_2,B_3_3,B_3_4,B_3_5,B_3_6,B_3_7],[B_4_1,B_4_2,B_4_3,B_4_4,B_4_5,B_4_6,B_4_7],[B_5_1,B_5_2,B_5_3,B_5_4,B_5_5,B_5_6,B_5_7],[B_6_1,B_6_2,B_6_3,B_6_4,B_6_5,B_6_6,B_6_7],[B_7_1,B_7_2,B_7_3,B_7_4,B_7_5,B_7_6,B_7_7]]),Matrix(7, 4, [[C_1_1,C_1_2,C_1_3,C_1_4],[C_2_1,C_2_2,C_2_3,C_2_4],[C_3_1,C_3_2,C_3_3,C_3_4],[C_4_1,C_4_2,C_4_3,C_4_4],[C_5_1,C_5_2,C_5_3,C_5_4],[C_6_1,C_6_2,C_6_3,C_6_4],[C_7_1,C_7_2,C_7_3,C_7_4]]))) = Trace(Mul(Matrix(2, 4, [[A_3_2,A_1_1+A_3_3,A_1_4+A_3_6,A_1_5+A_3_7],[A_4_2,A_2_1+A_4_3,A_4_6+A_2_4,A_2_5+A_4_7]]),Matrix(4, 4, [[B_2_2,B_2_3,B_2_6,B_2_7],[B_3_2,B_1_1+B_3_3,B_3_6+B_1_4,B_3_7+B_1_5],[B_6_2,B_6_3+B_4_1,B_6_6+B_4_4,B_6_7+B_4_5],[B_7_2,B_7_3+B_5_1,B_7_6+B_5_4,B_7_7+B_5_5]]),Matrix(4, 2, [[C_2_3,C_2_4],[C_1_1+C_3_3,C_1_2+C_3_4],[C_4_1+C_6_3,C_6_4+C_4_2],[C_5_1+C_7_3,C_5_2+C_7_4]])))+Trace(Mul(Matrix(2, 4, [[A_1_2-A_3_2,A_1_3-A_3_3,A_1_6-A_3_6,A_1_7-A_3_7],[A_2_2-A_4_2,A_2_3-A_4_3,-A_4_6+A_2_6,A_2_7-A_4_7]]),Matrix(4, 3, [[B_2_1+B_2_3,B_2_6+B_2_4,B_2_7+B_2_5],[B_3_1+B_3_3,B_3_6+B_3_4,B_3_7+B_3_5],[B_6_3+B_6_1,B_6_6+B_6_4,B_6_7+B_6_5],[B_7_3+B_7_1,B_7_6+B_7_4,B_7_7+B_7_5]]),Matrix(3, 2, [[C_1_1,C_1_2],[C_4_1,C_4_2],[C_5_1,C_5_2]])))+Trace(Mul(Matrix(2, 3, [[-A_1_1+A_3_1,-A_1_4+A_3_4,-A_1_5+A_3_5],[-A_2_1+A_4_1,-A_2_4+A_4_4,A_4_5-A_2_5]]),Matrix(3, 4, [[B_1_2,B_1_1+B_1_3,B_1_6+B_1_4,B_1_7+B_1_5],[B_4_2,B_4_1+B_4_3,B_4_6+B_4_4,B_4_7+B_4_5],[B_5_2,B_5_1+B_5_3,B_5_6+B_5_4,B_5_7+B_5_5]]),Matrix(4, 2, [[C_2_3,C_2_4],[C_3_3,C_3_4],[C_6_3,C_6_4],[C_7_3,C_7_4]])))+Trace(Mul(Matrix(2, 4, [[A_1_2,A_1_1+A_1_3,A_1_4+A_1_6,A_1_5+A_1_7],[A_2_2,A_2_1+A_2_3,A_2_4+A_2_6,A_2_5+A_2_7]]),Matrix(4, 4, [[B_2_2,B_2_3,B_2_6,B_2_7],[B_3_2,B_3_3,B_3_6,B_3_7],[B_6_2,B_6_3,B_6_6,B_6_7],[B_7_2,B_7_3,B_7_6,B_7_7]]),Matrix(4, 2, [[C_2_1,C_2_2],[-C_1_1+C_3_1,C_3_2-C_1_2],[C_6_1-C_4_1,C_6_2-C_4_2],[C_7_1-C_5_1,C_7_2-C_5_2]])))+Trace(Mul(Matrix(2, 3, [[A_1_1,A_1_4,A_1_5],[A_2_1,A_2_4,A_2_5]]),Matrix(3, 4, [[B_1_2-B_3_2,B_1_3-B_3_3,-B_3_6+B_1_6,B_1_7-B_3_7],[B_4_2-B_6_2,B_4_3-B_6_3,B_4_6-B_6_6,-B_6_7+B_4_7],[B_5_2-B_7_2,B_5_3-B_7_3,B_5_6-B_7_6,B_5_7-B_7_7]]),Matrix(4, 2, [[C_2_1+C_2_3,C_2_2+C_2_4],[C_3_1+C_3_3,C_3_2+C_3_4],[C_6_1+C_6_3,C_6_2+C_6_4],[C_7_1+C_7_3,C_7_2+C_7_4]])))+Trace(Mul(Matrix(2, 4, [[A_3_2,A_3_3,A_3_6,A_3_7],[A_4_2,A_4_3,A_4_6,A_4_7]]),Matrix(4, 3, [[B_2_1,B_2_4,B_2_5],[-B_1_1+B_3_1,-B_1_4+B_3_4,-B_1_5+B_3_5],[-B_4_1+B_6_1,-B_4_4+B_6_4,-B_4_5+B_6_5],[-B_5_1+B_7_1,-B_5_4+B_7_4,-B_5_5+B_7_5]]),Matrix(3, 2, [[C_1_1+C_1_3,C_1_2+C_1_4],[C_4_1+C_4_3,C_4_2+C_4_4],[C_5_1+C_5_3,C_5_4+C_5_2]])))+Trace(Mul(Matrix(2, 3, [[A_3_1+A_3_3,A_3_4+A_3_6,A_3_5+A_3_7],[A_4_1+A_4_3,A_4_4+A_4_6,A_4_5+A_4_7]]),Matrix(3, 3, [[B_1_1,B_1_4,B_1_5],[B_4_1,B_4_4,B_4_5],[B_5_1,B_5_4,B_5_5]]),Matrix(3, 2, [[C_1_3-C_3_3,C_1_4-C_3_4],[C_4_3-C_6_3,-C_6_4+C_4_4],[C_5_3-C_7_3,C_5_4-C_7_4]])))

N.B.: for any matrices A, B and C such that the expression Tr(Mul(A,B,C)) is defined, one can construct several trilinear homogeneous polynomials P(A,B,C) such that P(A,B,C)=Tr(Mul(A,B,C)) (P(A,B,C) variables are A,B and C's coefficients). Each trilinear P expression encodes a matrix multiplication algorithm: the coefficient in C_i_j of P(A,B,C) is the (i,j)-th entry of the matrix product Mul(A,B)=Transpose(C).

Algorithm description

These encodings are given in compressed text format using the maple computer algebra system. In each cases, the last line could be understood as a description of the encoding with respect to classical matrix multiplication algorithm. As these outputs are structured, one can construct easily a parser to its favorite format using the maple documentation without this software.


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