These are functions from the text Fundamentals of Numerical Computation, by Driscoll and Braun, 1st edition (2017). To use these functions, right-click the link and download to your MATLAB file directory.

Chapter 1: Numbers, problems, and algorithms

horner (Function 1.3.1)
Evaluate a polynomial using Horner's rule.

Chapter 2: Square linear systems

forwardsub (Function 2.3.1)
Solve a lower triangular linear system.
backsub (Function 2.3.2)
Solve an upper triangular linear system.
lufact (Function 2.4.1)
LU factorization for a square matrix.

Chapter 3: Overdetermined linear systems

lsnormal (Function 3.2.1)
Solve linear least squares by normal equations.
lsqrfact (Function 3.3.1)
Solve linear least squares by QR factorization.

Chapter 4: Roots of nonlinear equations

newton (Function 4.3.1)
Newton's method for a scalar equation.
secant (Function 4.4.1)
Secant method for a scalar equation.
newtonsys (Function 4.5.1)
Newton's method for a system of equations.
fdjac (Function 4.6.1)
Finite-difference approximation of a Jacobian.
levenberg (Function 4.6.2)
Quasi-Newton method for nonlinear systems.

Chapter 5: Piecewise interpolation

hatfun (Function 5.2.1)
Hat function/piecewise linear basis function.
plinterp (Function 5.2.2)
Piecewise linear interpolation.
spinterp (Function 5.3.1)
Cubic not-a-knot spline interpolation.
fdweights (Function 5.4.1)
Fornberg's algorithm for finite difference weights.
trapezoid (Function 5.6.1)
Trapezoid formula for numerical integration.
intadapt (Function 5.7.1)
Adaptive integration with error estimation.

Chapter 6: Initial-value problems

eulerivp (Function 6.2.1)
Euler's method for a scalar initial-value problem.
eulersys (Function 6.3.1)
Euler's method for a first-order IVP system.
ie2 (Function 6.4.1)
Improved Euler method for an IVP.
rk4 (Function 6.4.2)
Fourth-order Runge-Kutta for an IVP.
rk23 (Function 6.5.1)
Adaptive IVP solver based on embedded RK formulas.
ab4 (Function 6.7.1)
4th-order Adams-Bashforth formula for an IVP.
am2 (Function 6.7.2)
2nd-order Adams-Moulton (trapezoid) formula for an IVP.

Chapter 8: Krylov methods in linear algebra

poweriter (Function 8.2.1)
Power iteration for the dominant eigenvalue.
inviter (Function 8.3.1)
Shifted inverse iteration for the closest eigenvalue.
arnoldi (Function 8.4.1)
Arnoldi iteration for Krylov subspaces.
arngmres (Function 8.5.1)
GMRES for a linear system.

Chapter 9: Global function approximation

polyinterp (Function 9.2.1)
Polynomial interpolation by the barycentric formula.
triginterp (Function 9.5.1)
Trigonometric interpolation.
ccint (Function 9.6.1)
Clenshaw-Curtis numerical integration.
glint (Function 9.6.2)
Gauss-Legendre numerical integration.
intde (Function 9.7.1)
Doubly exponential integration over (-inf, inf).
intsing (Function 9.7.2)
Integrate function with endpoint singularities.

Chapter 10: Boundary-value problems

shoot (Function 10.1.1)
Shooting method for a two-point boundary-value problem.
diffmat2 (Function 10.2.1)
Second-order accurate differentiation matrices.
diffcheb (Function 10.2.2)
Chebyshev differentiation matrices.
bvplin (Function 10.3.1)
Solve a linear boundary-value problem.
bvp (Function 10.4.1)
Solve a nonlinear boundary-value problem.
fem (Function 10.5.1)
Piecewise linear finite elements for a linear BVP.

Chapter 11: Diffusion equations

diffper (Function 11.2.1)
Differentiation matrices for periodic end conditions.

Chapter 13: Two-dimensional problems

rectdisc (Function 13.2.1)
Discretization on a rectangle.
poissonfd (Function 13.3.1)
Solve Poisson's equation by finite differences.
newtonpde (Function 13.4.1)
Newton's method to solve an elliptic PDE.