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Tools / Numerical Demo

Nonlinear Solver Visualizer

Visualise not only the answer, but also Newton iterations and Homotopy path tracking for nonlinear systems with up to ten variables.

Problem and method

Use a built-in problem or enter a custom system of 1–10 equations. All calculations run locally in the browser.

Initial value / start point

Step —λ —
Step—
λ—
Path arclength s—
Residual norm—
Current vector—

One-variable Newton method

The horizontal axis is x and the vertical axis is f(x). Cyan is the function, the yellow dashed line is the tangent, pink is the current point, and green is the next candidate obtained from the tangent.

Newton Iteration Path

Vertical axisIteration k

Variable History

The horizontal axis is the iteration step and the vertical axis is each variable value. Line colours correspond to x1–x10 shown in the chart.

Residual History

The horizontal axis is the iteration step and the vertical axis is the logarithmic residual norm ||F(x)||. Lower values mean the iterate is closer to a solution.

Iteration History

StepλArc length sResidualStep / Correctorx

What this demo shows

Newton's method solves for a correction using the Jacobian. Homotopy treats z=(x,λ) as one unknown vector and advances arclength s along the solution path rather than forcing λ to increase. A tangent predictor is corrected by solving H(x,λ)=0 together with a perpendicular hyperplane condition, so the path can continue through folds where λ decreases.

J(xₖ) Δx = −F(xₖ)H(x,λ) = (1−λ)G(x) + λF(x)[Hₓ Hλ] t = 0tᵀ(z − z predictor) = 0

Newton method | Homotopy method