stenglib

Stefan Engblom's Matlab libraries - packages for daily use.

License statement for stenglib

You may download all of stenglib and use, modify and redistribute it in any way you like. A redistributor must fully attribute the authorship and make a good effort to cite the original location of the software. A researcher making critical use of the software in research is requested to acknowledge this in publications related to the research. A company may use the code in software products provided that the original location and the author is clearly cited.

All code provided here comes with absolutely no warranty and no support whatsoever is given.

There are a lot of freeware available on the net. Do not download unless you agree to the above license.

About stenglib

stenglib is loosely divided into 5 sub-packages, with few dependencies in between them:

• Tensor
• Fast
• Scicomp
• Utils
• Misc

For contact details, see stenglib.org. I welcome bug reports and comments. Please do not send support requests.

Tensor

Originally, I made the Tensor package because I had the need to easily, efficiently and consistently manage multi-dimensional arrays in Matlab. Examples: given a matrix and a vector, how do you scale each row in the matrix by the vector? How can you multiply a 3-D array with a matrix? The package is useful to anyone who writes code for (pseudo-) spectral methods, FEM, or who uses multi-dimensional arrays or tensor notation a lot.

• tndims Number of dimensions. (Depend: 0, status: stable) tndims.m tndims.c

• tsize Size of array. (Depend: 0, status: stable) tsize.m tsize.c

• tsum Tensor summation. (Depend: 0, status: stable) tsum.m tsum.c

• tprod Tensor product. Based on a concept by D. Bertilsson, COMSOL. (Depend: 0, status: stable) tprod.m tprod.c

There is also a make.m available. It will work on several, but not all, platforms.

Fast

The routines in the Fast package exist because some things just take too much time in Matlab. Examples: replicate a data set in different dimensions (a.k.a. repmat), assemble a sparse matrix, or evaluate set operations. These routines should be of general interest to programmer in the scientific computing community.

• frepmat Fast replication of array. (Depend: Tensor/{tndims,tsize} (weakly), status: stable) frepmat.m mexfrepmat.c

• fsparse Fast assembly of sparse matrix. (Depend: 0, status: stable but not completely settled) fsparse.m fsparse.c

There is now a parallel fsparse version available. A paper describing the algorithm is S. Engblom, D. Lukarski: Fast Matlab compatible sparse assembly on multicore computers, in Parallel Comput. 56:1--17 (2016) (doi). Fact: the fsparse-code has been selected as the base for the sparse assembly routines in PARALUTION.

• clenshaw Evaluation of 3-term recurrences. (Depend: 0, status: stable) clenshaw.m clenshaw.c

• fsetop Fast set operations based on hashing. Based on a concept by P.-O. Persson and a hash-function by P. Hsieh (Depend: 0, status: stable) fsetop.m fsetop.c

• sppmul Sparse pattern multiply. (Depend: 0, status: stable) Download: sppmul.m sppmul.c

• powerseries Sum power series. (Depend: 0, status: stable) powerseries.m powerseries.c

As before there is a make.m available which you will probably have to modify.

Scicomp

In Scicomp I've assembled some solvers from different areas within scientific computing: two solvers for nonlinear problems and an implementation of the Nelder-Mead simplex algorithm. I have also put three routines for Gaussian quadratures with respect to discrete measures in this package.

• rtsafe Scalar nonlinear solver. (Depend: 0, status: stable) rtsafe.m

• ainsolve Solver for large sets of nonlinear equations. (Depend: 0, status: experimental) ainsolve.m

• nmsimplex Nelder-Meads simplex-algorithm. (Depend: Fast/frepmat, Utils/parseopts, status: stable) nmsimplex.m

• ode1s ODE-solver: split-step Euler method with digital control. (Depend: Fast/{frepmat,fsetop}, Utils/{parseopts,report}, status: stable, but not finalized) ode1s.m

• gaussqd Gaussian quadrature for discrete measures. (Depend: Tensor/tprod, Fast/fsparse, status: stable) gaussqd.m

• gausspd Gaussian polynomial for discrete measures. (Depend: Tensor/{tsum,tprod}, Fast/clenshaw, status: stable) gausspd.m

• poch Pochhammer's function. (Depend: 0, status: stable) poch.m

Utils

In the package Utils I've collected various routines for performing everyday tasks. Examples include generating LaTeX-arrays from matrices, .gif-animations, small perfect hash functions and removing files ending with a tilde (!).

• arr2latex LaTeX-table from matrix. (Depend: Fast/frepmat, Utils/parseopts, status: stable) arr2latex.m

• assignopts Assign options. (Depend: 0, status: stable) assignopts.m

• parseopts Parse options. (Depend: Fast/fsetop, status: stable) parseopts.m

• matmerge Merge .mat-files. (Depend: Fast/fsetop, Tensor/{tsize,tndims}, status: stable but kind of a hack) matmerge.m

• consistency Local truncation error of linear multistep method. (Depend: 0, status: stable) consistency.m

• stability Plot of stability region for linear multistep method. (Depend: 0, status: stable) stability.m

• perfecthash Perfect hash-function from strings. (Depend: Tensor/tsum, Fast/fsparse, status: this is a hack, really) perfecthash.m

• movie2gif Create GIF animation from MATLAB movie. (Depend: imwrite-function in Matlab, status: stable) movie2gif.m

• report Report progress of solver. (Depend: 0, status: stable) report.m

• runtest General test facility. (Depend: 0, status: stable) runtest.m

• rmtilde Remove files ending with a tilde ('~'). (Depend: 0, status: stable) rmtilde.m

• connect Connectivity information for points. (Depend: 0, status: stable) connect.m

• ndop General N-dimensional operator. (Depend: Tensor/{tndims,tsum,tprod}, Fast/frepmat, status: stable) ndop.m

• spblock Sparse matrix from blocks. (Depend: Fast/fsparse, status: stable) spblock.m

• spym Visualize magnitude of elements in matrix. (Depend: 0, status: this is a hack) spym.m

Misc

I'll put amusing routines in Misc. For now, this humble package contains a sudoku solver and a short function which I personally believe is the most beautiful Matlab-code ever written.

• sudsolve Solve Sudoku puzzle. (Depend: 0, status: stable) sudsolve.m

• repeat Repeat elements of vector. (Depend: 0, status: stable) repeat.m