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# Jan Valdman

41 total contributions since 2010

Associate professor of applied mathematics

Professional Interests: FEM, nonlinear computational mechanics, a posteriori error estimates, MATLAB vectorizations

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Submitted

Implementation of C1 FEM
Detailed implementation of Bogner-Fox-Schmit elements.

Submitted

Hyper elasticity with a non-penetration condition
A 2D FEM solver based on an energy minimisation formulated in C^1 deformation including a new non-penetration term.

Submitted

Element-based Solvers
2D Poisson's solver using only local FEM matrices without the global matrix assembly.

Solved

Finding Perfect Squares
Given a vector of numbers, return true if one of the numbers is a square of one of the other numbers. Otherwise return false. E...

10 months ago

Solved

Pizza!
Given a circular pizza with radius _z_ and thickness _a_, return the pizza's volume. [ _z_ is first input argument.] Non-scor...

10 months ago

Question

Is there any gradient descent method available?
We are working on the optimization of nonconvex energies in mechanics of solid (see the attached picture) resulting from the fin...

11 months ago | 1 answer | 0

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Solved

Fibonacci sequence
Calculate the nth Fibonacci number. Given n, return f where f = fib(n) and f(1) = 1, f(2) = 1, f(3) = 2, ... Examples: Inpu...

12 months ago

Solved

Select every other element of a vector
Write a function which returns every other element of the vector passed in. That is, it returns the all odd-numbered elements, s...

12 months ago

Solved

Find the sum of all the numbers of the input vector
Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

12 months ago

Solved

Interpolator
You have a two vectors, a and b. They are monotonic and the same length. Given a value, va, where va is between a(1) and a(end...

12 months ago

Solved

Given a and b, return the sum a+b in c.

12 months ago

Submitted

Evolutionary model for shape memory alloys
Software for a new article - more details later

Submitted

Fast elastoplastic FEM assembly
Vectorized assembly of FEM matrices and including complete calculations of elastoplasticity benchmarks.

Submitted

Fast FEM assembly: nodal elements
Vectorized assembly of FEM matrices.

Submitted

Fast FEM assembly: edge elements
Vectorized assembly of FEM matrices.

Submitted

Computation of the Friedrichs and Poincare constants in 2D/3D
Computation of Friedrichs and Poincare constants in 2D/3D from generalized eigenvalue problems.

Question

Matlab Exchange - More authors to one contribution
We are three persons in a team finishing up a Matlab package to upload. I already have an account, but my colleagues not. If the...

1 year ago | 2 answers | 1

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Submitted

Error identities for variational problems with obstacles
Calculaton of Error identities for variational problems with obstacles

Submitted

Continuum undergoing combined elasto-plasto-damage transformation.
Time-dependent evolution of the continuum undergoing combined elasto-plasto-damage transformation.

Solved

Determine whether a vector is monotonically increasing
Return true if the elements of the input vector increase monotonically (i.e. each element is larger than the previous). Return f...

2 years ago

Solved

Find all elements less than 0 or greater than 10 and replace them with NaN
Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

2 years ago

Solved

Triangle Numbers
Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

2 years ago

Solved

Make the vector [1 2 3 4 5 6 7 8 9 10]
In MATLAB, you create a vector by enclosing the elements in square brackets like so: x = [1 2 3 4] Commas are optional, s...

2 years ago

Solved

Times 2 - START HERE
Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

2 years ago

Submitted

Lagrange polynomial and its subpolynomials
Construction of the Lagrange interpolation polynomial from its definition.

Question

vectorization of anonymous function?
I managed to vectorize the function below using inline command: u_function=inline(vectorize('sin(x*y*z^2)'),'x','y','z') x=[...

2 years ago | 1 answer | 0

### 1

Submitted

Two-phase obstacle problem in 2D and its aposteriori error estimate
Calculation of two-phase obstacle problem in 2D and its a posteriori error estimate

Submitted

Edges generation
Algorithm generates edges of a conforming 2D/3D triangulation.

Submitted

Quadrature of the absolute value of a function
Quadrature of the absolute value of a function