DEQ
Check IVP integration
Checks solve_ivp to known solution. UNDER CONSTRUCTION
2026.Jun.03 20:08:59
t0, tF, t*   (tR := min(tf, tR)) Times: from, to (integration) and report.
Parameters Problem parameters.
Target F values Target function values at t*.
Integration method        Method of integration.
Tolerances Relative and absolute tolerances for integration.
Minimization method Python 'optimization minimization' method.
Points N. of plot points (0, auto)
Show values Show graph coordinates.

Integrates the ODEs. Reports the function values at t*. Compares with known function.

The embedded ODE:  x' = #ETC. -a²b sin(2bt) ⁄ [1 + a²cos²(bx)]², with given initial values.

This applies, from Python: for integration, 'scipy.integrate' odeint; and, for optimization, minimize.

Draws a plot of the integrated and known functions.

Computation structure: a PHP file (this page: 'P.check.php') calls (via 'action=...') an intermediate PHP file ('Check.php'), which (through $_POST) sends the problem data as command line arguments to a Python script. This last does the computing, and makes 'system' call(s) to 'gnuplot', for the final (temporary) web page.

Keywords: ODEs one; solve_ivp; Python; gnuplot.

References: Plate: checkIVP

• Python minimize [in Optimization and root finding (scipy.optimize)].

• Gnuplot dashtype • HTML Color Codes • Python f-string • (Python) unicode characters

• CISTI'2027, 22.ª Conferência Ibérica de Sistemas e Tecnologias de Informaçaão (22.nd Iberian Conference on Information Systems and Technologies), #... (Portugal), #25–28 June 2027.

• 1902-04-04: Hopf, Eberhard Frederich Ferdinand (†1983-07-24, 81 yrs.).

 
 
Valid HTML 5! IST http://web.ist.utl.pt/mcasquilho/compute/reverse/checkIVP/P.check.php
Created: 2026-04-19 — Last modified: 2026-04-19