The two-volume set LNCS 11973 and 11974 constitute revised selected papers from the Third International Conference on Numerical Computations: Theory and Algorithms, NUMTA 2019, held in Crotone, Italy, in June 2019.

Approximation: Methods, Algorithms, and Applications.- Towards an Efficient Implementation of an Accurate SPH Method.- A Procedure for Laplace Transform Inversion Based on Smoothing Exponential-Polynomial.- Splines.- An Adaptive Refinement Scheme for Radial Basis Function Collocation.- A 3D efficient Procedure for Shepard Interpolants on Tetrahedra.- Interpolation by Bivariate Quadratic Polynomials and Applications to the Scattered Data Interpolation Problem.- Comparison of Shepard's Like Methods with Different Basis Functions.- A New Remez-type Algorithm for Best Polynomial Approximation.- An SVE Approach for the Numerical Solution of Ordinary Differential Equations.- Uniform Weighted Approximation by Multivariate Filtered Polynomials.- Computational Methods for Data Analysis.- A Travelling Wave Solution for Nonlinear Colloid Facilitated Mass Transport in Porous Media.- Performance Analysis of a Multicore Implementation for Solving a Two-dimensional Inverse Anomalous Diffusion Problem.- Adaptive RBF Interpolation for Estimating Missing Values in Geographical Data.- Stochastic Mechanisms of Information Flow in Phosphate Economy of Escherichia Coli.- NMR Data Analysis of Water Mobility in Wheat Flour Dough: A Computational Approach.- First Order Methods in Optimization: Theory and Applications.- A Limited Memory Gradient Projection Method for Box-Constrained Quadratic Optimization.- Problems.- A Gradient-Based Globalization Strategy for the Newton Method.- On the Steplength Selection in Stochastic Gradient Methods.- Efficient Block Coordinate Methods for Blind Cauchy Denoising.- High Performance Computing in Modelling and Simulation.- A Parallel Software Platform for Pathway Enrichment.- Hierarchical Clustering of Spatial Urban Data.- Improving Efficiency in Parallel Computing Leveraging Local Synchronization.- A General Computational Formalism for Networks of Structured Grids.- Preliminary Model of Saturated.- Flow Using Cellular Automata.- A Cybersecurity Framework for Classifying Non Stationary Data Streams Exploiting Genetic Programming and Ensemble Learning.- A Dynamic Load Balancing Technique for Parallel Execution of Structured Grid Models.- Final Sediment Outcome from Meteorological Flood Events: A Multi-Modelling Approach.- Parallel Algorithms for Multifractal Analysis of River Networks.- A Methodology Approach to Compare Performance of Parallel Programming Models for.- Shared-Memory Architectures.- Numbers, Algorithms, and Applications.- New Approaches to Basic Calculus: An Experimentation via Numerical Computation.- A Multi-factor RSA-like Scheme with Fast Decryption Based on Rédei Rational Functions over the Pell Hyperbola.- Paradoxes of the Infinite and Ontological Dilemmas between Ancient Philosophy and Modern Mathematical Solutions.- The Sequence of Carboncettus Octagons.- On the Arithmetic of Knuth's Powers and Some Computational Results about Their Density.- Combinatorics on n-sets: Arithmetic Properties and Numerical Results.- Numerical Problems in XBRL Reports and the Use of Blockchain as Trust Enabler.- Modelling on Human Intelligence a Machine Learning System.- Algorithms for Jewelry Industry 4.0.- Clustering Analysis to Profile Customers' Behaviour in POWER CLOUD Energy Community.- A Grossone-based Numerical Model for Computations with Infinity: A Case Study in an Italian High School.- A Computational Approach with MATLAB Software for Nonlinear Equation Roots Finding in High School Maths.- Task Mathematical Modelling Design in a Dynamic Geometry Environment: Archimedean Spiral's Algorithm.- Optimization and Management of Water Supply.- Numerical Experimentations for a New Set of Local Indices of a Water Network.- Performance Management of Demand and Pressure Driven Analysis in a Monitored Water.- Distribution Network.- Algebraic Tools and New Local Indices for Water Networks: Some Numerical Examples.- Identification of Contamination Potential Source (ICPS): A Topological Approach for the Optimal.- Recognition of Sensitive Nodes in a Water Distribution Network.- Seeking for a Trade-off between Accuracy and Timeliness in Meteo-hydrological Modeling Chains.- Optimization Model for Water Distribution Network Planning in a Realistic Orographic Framework.- Scenario Optimization of Complex Water Supply Systems for Energy Saving and Drought-risk Management.- Optimizing Rainwater Harvesting Systems for Non-potable Water Uses and Surface Runoff Mitigation.- New Mathematical Optimization Approaches for LID Systems.- Evaluation of an Integrated Seasonal Forecast System for Agricultural Water Management in Mediterranean Regions.- Optimization of Submarine Outfalls with a Multiport Diffuser Design.