Description of fast matrix multiplication algorithm: ⟨2×5×16:126⟩

Algorithm type

12⁢X2⁢Y4⁢Z2+22⁢X2⁢Y2⁢Z2+16⁢X⁢Y4⁢Z+16⁢X⁢Y3⁢Z+8⁢X⁢Y2⁢Z+52⁢X⁢Y⁢Z12X2Y4Z222X2Y2Z216XY4Z16XY3Z8XY2Z52XYZ12*X^2*Y^4*Z^2+22*X^2*Y^2*Z^2+16*X*Y^4*Z+16*X*Y^3*Z+8*X*Y^2*Z+52*X*Y*Z

Algorithm definition

The algorithm ⟨2×5×16:126⟩ could be constructed using the following decomposition:

⟨2×5×16:126⟩ = ⟨2×5×4:32⟩ + ⟨2×5×12:94⟩.

This decomposition is defined by the following equality:

Trace⁡Mul⁡A_1_1A_1_2A_1_3A_1_4A_1_5A_2_1A_2_2A_2_3A_2_4A_2_5B_1_1B_1_2B_1_3B_1_4B_1_5B_1_6B_1_7B_1_8B_1_9B_1_10B_1_11B_1_12B_1_13B_1_14B_1_15B_1_16B_2_1B_2_2B_2_3B_2_4B_2_5B_2_6B_2_7B_2_8B_2_9B_2_10B_2_11B_2_12B_2_13B_2_14B_2_15B_2_16B_3_1B_3_2B_3_3B_3_4B_3_5B_3_6B_3_7B_3_8B_3_9B_3_10B_3_11B_3_12B_3_13B_3_14B_3_15B_3_16B_4_1B_4_2B_4_3B_4_4B_4_5B_4_6B_4_7B_4_8B_4_9B_4_10B_4_11B_4_12B_4_13B_4_14B_4_15B_4_16B_5_1B_5_2B_5_3B_5_4B_5_5B_5_6B_5_7B_5_8B_5_9B_5_10B_5_11B_5_12B_5_13B_5_14B_5_15B_5_16C_1_1C_1_2C_2_1C_2_2C_3_1C_3_2C_4_1C_4_2C_5_1C_5_2C_6_1C_6_2C_7_1C_7_2C_8_1C_8_2C_9_1C_9_2C_10_1C_10_2C_11_1C_11_2C_12_1C_12_2C_13_1C_13_2C_14_1C_14_2C_15_1C_15_2C_16_1C_16_2=Trace⁡Mul⁡A_1_1A_1_2A_1_3A_1_4A_1_5A_2_1A_2_2A_2_3A_2_4A_2_5B_1_1B_1_2B_1_3B_1_4B_2_1B_2_2B_2_3B_2_4B_3_1B_3_2B_3_3B_3_4B_4_1B_4_2B_4_3B_4_4B_5_1B_5_2B_5_3B_5_4C_1_1C_1_2C_2_1C_2_2C_3_1C_3_2C_4_1C_4_2+Trace⁡Mul⁡A_1_1A_1_2A_1_3A_1_4A_1_5A_2_1A_2_2A_2_3A_2_4A_2_5B_1_5B_1_6B_1_7B_1_8B_1_9B_1_10B_1_11B_1_12B_1_13B_1_14B_1_15B_1_16B_2_5B_2_6B_2_7B_2_8B_2_9B_2_10B_2_11B_2_12B_2_13B_2_14B_2_15B_2_16B_3_5B_3_6B_3_7B_3_8B_3_9B_3_10B_3_11B_3_12B_3_13B_3_14B_3_15B_3_16B_4_5B_4_6B_4_7B_4_8B_4_9B_4_10B_4_11B_4_12B_4_13B_4_14B_4_15B_4_16B_5_5B_5_6B_5_7B_5_8B_5_9B_5_10B_5_11B_5_12B_5_13B_5_14B_5_15B_5_16C_5_1C_5_2C_6_1C_6_2C_7_1C_7_2C_8_1C_8_2C_9_1C_9_2C_10_1C_10_2C_11_1C_11_2C_12_1C_12_2C_13_1C_13_2C_14_1C_14_2C_15_1C_15_2C_16_1C_16_2

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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