Accelerating recurrent neural network training using sequence bucketing and multi-GPU data parallelization

An efficient algorithm for recurrent neural network training is presented. The approach increases the training speed for tasks where a length of the input sequence may vary significantly. The proposed approach is based on the optimal batch bucketing by input sequence length and data parallelization on multiple graphical processing units. The baseline training performance without sequence bucketing is compared with the proposed solution for a different number of buckets. An example is given for the online handwriting recognition task using an LSTM recurrent neural network. The evaluation is performed in terms of the wall clock time, number of epochs, and validation loss value.Comment: 4 pages, 5 figures, Comments, 2016 IEEE First International Conference on Data Stream Mining & Processing (DSMP), Lviv, 201

Trifluoromethyl Phosphoranides, First Phosphoranides with Csp3-P Bonds: Synthesis, Derivatives and Properties.

The new tris(trifluoromethyl)fluorophosphoranide and tetrakis(trifluoromethyl)phosphoranide salts were synthesized. High relative stability of these derivatives allowed theirs full characterization including X-Ray analysis as well as comprehensive studying of theirs chemical properties. Thermal stability and fluxional behavior of the salts in solution in dependence on the nature of cation were investigated. Energy barriers to pseudorotation in trifluoromethyl phosphoranides were compared with those for trifluoromethyl phosphoranes. Ab-initio calculations of electronic and geometrical parameters as well as selected gas-phase acidities for phosphoranides were performed and close interrelationships of different parameters for each group of substituents (axial, equatorial) were established. A new class of compounds was discovered during studying the chemistry of phosphoranides. Mixed-valence species (l3s3P-l5s6P system) were unexpectedly obtained in the reactions of trifluoromethylphosphoranides with fluoride ion sources in monoglyme. These derivatives were characterized by NMR and MS spectral methods however, numerous attempts to grow single crystals applicable for X-Ray analysis failed compounds quickly decomposed in solution even at -40 Ã ?Ã ºC to give corresponding phosphate salts.Perphosphoranides were obtained in high yields in the reaction of corresponding trifluoromethyl phosphines with DFI. These compounds were fully described including X-Ray analysis.Syntheses of starting compounds (trifluoromethyl-phosphines, DFI, DFTMU) were optimized significantly and new convenient large-scale routes to ones were found

Trifluoromethyl Phosphoranide, erste Phosphoranide mit Csp3-P Bindungen: Synthese, Eigenschaften und Derivate

The new tris(trifluoromethyl)fluorophosphoranide and tetrakis(trifluoromethyl)phosphoranide salts were synthesized. High relative stability of these derivatives allowed theirs full characterization including X-Ray analysis as well as comprehensive studying of theirs chemical properties. Thermal stability and fluxional behavior of the salts in solution in dependence on the nature of cation were investigated. Energy barriers to pseudorotation in trifluoromethyl phosphoranides were compared with those for trifluoromethyl phosphoranes. Ab-initio calculations of electronic and geometrical parameters as well as selected gas-phase acidities for phosphoranides were performed and close interrelationships of different parameters for each group of substituents (axial, equatorial) were established. A new class of compounds was discovered during studying the chemistry of phosphoranides. Mixed-valence species (l3s3P-l5s6P system) were unexpectedly obtained in the reactions of trifluoromethylphosphoranides with fluoride ion sources in monoglyme. These derivatives were characterized by NMR and MS spectral methods however, numerous attempts to grow single crystals applicable for X-Ray analysis failed compounds quickly decomposed in solution even at -40 à ?à ºC to give corresponding phosphate salts.Perphosphoranides were obtained in high yields in the reaction of corresponding trifluoromethyl phosphines with DFI. These compounds were fully described including X-Ray analysis.Syntheses of starting compounds (trifluoromethyl-phosphines, DFI, DFTMU) were optimized significantly and new convenient large-scale routes to ones were found

Synthesis, Reactivity and Structural Properties of Trifluoromethylphosphoranides

Shyshkov OO, Kolomeitsev AA, Hoge B, et al. Synthesis, Reactivity and Structural Properties of Trifluoromethylphosphoranides. Chemistry . 2022.Phosphoranides are interesting hypervalent species which serve as model compounds for intermediates or transition states in nucleophilic substitution reactions at trivalent phosphorus substrates. Herein, we report on the syntheses and properties of stable trifluoromethylphosphoranide salts. [K(18-crown-6)][P(CF 3 ) 4 ], [K(18-crown-6)][P(CF 3 ) 3 F], and [NMe 4 ][P(CF 3 ) 2 F 2 ] were obtained by treatment of trivalent precursors with sources of CF 3 - or F - units. These [P(CF 3 ) 4-n F n ] - (n = 0-2) salts exhibit fluorinating (n = 1-2) or trifluoromethylating (n = 0) properties, which is disclosed by studying their reactivity towards selected electrophiles. The solid-state structures of [K(18-crown-6)][P(CF 3 ) 4 ] and [K(18-crown-6)][P(CF 3 ) 3 F] are ascertained by single crystal X-ray crystallography. The dynamics of these compounds are investigated by variable temperature NMR spectroscopy. © 2022 Wiley-VCH GmbH

Carbene Complexes of Phosphorus(V) Fluorides by Oxidative Addition of 2,2-Difluorobis(dialkylamines) to Phosphorus(III) Halides

Carbene-stabilized complexes of substituted and unsubstituted phosphorus­(V) fluorides were obtained by oxidative addition of 2,2-difluorobis­(dialkylamines) to phosphorus­(III) halides. Octahedral and hydrolytically stable complexes were obtained in quantitative yields. All compounds were characterized in the solid state by single-crystal X-ray diffraction

Carbene Complexes of Phosphorus(V) Fluorides by Oxidative Addition of 2,2-Difluorobis(dialkylamines) to Phosphorus(III) Halides

Carbene-stabilized complexes of substituted and unsubstituted phosphorus­(V) fluorides were obtained by oxidative addition of 2,2-difluorobis­(dialkylamines) to phosphorus­(III) halides. Octahedral and hydrolytically stable complexes were obtained in quantitative yields. All compounds were characterized in the solid state by single-crystal X-ray diffraction