Search for dissertations about: "sparse matrix"

Showing result 1 - 5 of 62 swedish dissertations containing the words sparse matrix.

  2. 1. Sparse Matrices in Self-Consistent Field Methods

    Author : Emanuel Rubensson; Pawel Salek; Hans Ågren; Anders Niklasson; Axel Ruhe; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; sparse matrix; self-consistent field; Hartree-Fock; Density Functional Theory; Density Matrix Purification; Theoretical chemistry; Teoretisk kemi;

    Abstract : This thesis is part of an effort to enable large-scale Hartree-Fock/Kohn-Sham (HF/KS) calculations. The objective is to model molecules and materials containing thousands of atoms at the quantum mechanical level. HF/KS calculations are usually performed with the Self-Consistent Field (SCF) method. READ MORE

  4. 2. Cooperative Compressive Sampling

    Author : Ahmed Zaki; Lars Kildehøj; Saikat Chatterjee; Jan Østergaard; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Compressive sampling; greedy algorithms; convex optimisation; RIP analysis; fusion strategy; distributed learning; sparse learning; stochastic matrix; consensus; sparse estimation; Telecommunication; Telekommunikation;

    Abstract : Compressed Sampling (CS) is a promising technique capable of acquiring and processing data of large sizes efficiently. The CS technique exploits the inherent sparsity present in most real-world signals to achieve this feat. Most real-world signals, for example, sound, image, physical phenomenon etc., are compressible or sparse in nature. READ MORE

  5. 3. Parallelization of dynamic algorithms for electronic structure calculations

    Author : Anton G. Artemov; Emanuel H. Rubensson; Maya Neytcheva; Bo Kågström; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; parallelization; task-based programming; matrix algorithms; sparse matrices; inverse factorization; localized computations; density matrix methods; electronic structure calculations; Scientific Computing; Beräkningsvetenskap;

    Abstract : The aim of electronic structure calculations is to simulate behavior of complex materials by resolving interactions between electrons and nuclei in atoms at the level of quantum mechanics. Progress in the field allows to reduce the computational complexity of the solution methods to linear so that the computational time scales proportionally to the size of the physical system. READ MORE

  6. 4. Matrix Algebra for Quantum Chemistry

    Author : Emanuel H. Rubensson; Pawel Salek; Stefan Goedecker; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; linear scaling; reduced complexity; electronic structure; density functional theory; Hartree-Fock; density matrix purification; congruence transformation; inverse factorization; eigenvalues; eigenvectors; numerical linear algebra; occupied subspace; canonical angles; invariant subspace; Theoretical chemistry; Teoretisk kemi;

    Abstract : This thesis concerns methods of reduced complexity for electronic structure calculations.  When quantum chemistry methods are applied to large systems, it is important to optimally use computer resources and only store data and perform operations that contribute to the overall accuracy. READ MORE

  7. 5. Comparative network analysis of human cancer: sparse graphical models with modular constraints and sample size correction

    Author : José Sánchez; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Inverse covariance matrix; precision matrix; graphical models; high-dimension; low-sample; networks; sparsity; fused lasso; elastic net; cancer.; fused lasso;

    Abstract : In the study of transcriptional data for different groups (e.g. cancer types) it's reasonable to assume that some dependencies between genes on a transcriptional or genetic variants level are common across groups. Also, that this property is preserved locally, thus defining a modular structure in the model networks. READ MORE