# Questions tagged [dae]

A (system of) Differential Algebraic Equations (DAE) is a system of equations with ordinary differential equations and algebraic equations; all the equations should be satisfied simultaneously.

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### Choice between DAE or ODE formulation for chemical systems

Consider a simple ODE system describing the evolution of two chemical species undergoing the reaction $A = B$ : $$\frac{dn_A}{dt} = - k * n_A$$ $$\frac{dn_B}{dt} = k * n_A$$ We can discretize ...
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### SUNDIALS using Python Interface tutorial

I am attempting to solve differential algebraic equations using SUNDIALS with a Python interface. I am having trouble learning to actually use sundials, and cannot seem to find any tutorials online ...
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### solving a Algebraic Differential Equation in Julia using modelingToolKit.JL

I'm trying to solve a differential algebraic equation in Julia's modelingTookKit.JL, where the vector field has the form f(X) = 0. I found an example of a DAE in the below link modelingToolkit.JL DAE](...
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1 vote
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### How to solve an implicit ODE with forward Euler?

Consider the implicit ODE $$M(y)\dot{y} = F(t,y)$$ If $M$ is non-singular for all $y$ How to use the forward-Euler method to numerically solve for $y$ without inverting $M(y)$? I only came out ...
1 vote
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### Procedure to identify characteristic properties of unknown functions in a DAE model

I have a system of 1st order odes given by $$\dot{x_1}(t) = \alpha_1 f_1(x_1,t) + \beta_1 u(t) \\ \dot{x_2}(t) = \alpha_2 f_2(x_2,t) + \beta_2 u(t)$$ They are constrained by an algebraic equation ...
1 vote
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### Choice of solver/software for global optimisation of cheap black-box function with known derivatives

I am trying to estimate a few unknown parameters of my continuous non-linear PDAE model (simulated through finite-volume method spatial discretisation, and time-stepping through method-of-lines). I am ...
1 vote
419 views

### Does anyone have a driver for fortran DAE solver - COLDAE?

Coldae is a solver writter by U Ascher and R Spiteri, located here http://www.cs.ubc.ca/~ascher/coldae.f . It can solve upto index-2 DAEs using collocation. I am new to Fortran, and having a hard ...