Differences between revisions 39 and 40
Revision 39 as of 2021-06-24 11:40:16
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Editor: tmonteil
Comment:
Revision 40 as of 2023-08-30 07:44:36
Size: 18162
Editor: pang
Comment: fix geodesics on a parametri surface
Deletions are marked like this. Additions are marked like this.
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== Geodesics on a parametric surface FIXME == == Geodesics on a parametric surface ==
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    ufunc = function('ufunc', t)
    vfunc = function('vfunc', t)
    
    dFtt = F(u=ufunc, v=vfunc
).diff(t, t)
    
    ec1 = dFtt.dot_product(dFu(u=ufunc, v=vfunc))
    ec2 = dFtt.dot_product(dFv(u=ufunc, v=vfunc))
    

    ufunc = function('ufunc')
    vfunc = function('vfunc')

    dFtt = F(u=ufunc(t), v=vfunc(t)
).diff(t, t)

    ec1 = dFtt.dot_product(dFu(u=ufunc(t), v=vfunc(t)))
    ec2 = dFtt.dot_product(dFv(u=ufunc(t), v=vfunc(t)))
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         diffec1 = ec1.subs_expr(diff(ufunc, t) == du,
                            diff(ufunc, t, t) == ddu,
                            diff(vfunc, t) == dv,
                            diff(vfunc, t, t) == ddv,
                            ufunc == u, vfunc == v)
    diffec2 = ec2.subs_expr(diff(ufunc, t) == du,
                            diff(ufunc, t, t) == ddu,
                            diff(vfunc, t) == dv,
                            diff(vfunc, t, t) == ddv,
                            ufunc == u, vfunc == v)

    diffec1 = ec1.substitute(diff(ufunc(t), t) == du,
                            diff(ufunc(t), t, t) == ddu,
                            diff(vfunc(t), t) == dv,
                            diff(vfunc(t), t, t) == ddv,
                            ufunc(t) == u, vfunc(t) == v)
    diffec2 = ec2.substitute(diff(ufunc(t), t) == du,
                            diff(ufunc(t), t, t) == ddu,
                            diff(vfunc(t), t) == dv,
                            diff(vfunc(t), t, t) == ddv,
                            ufunc(t) == u, vfunc(t) == v)
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    Point = map(float, Point)
    velocity = map(float, velocity)
    
    Point = list(map(float, Point))
    velocity = list(map(float, velocity))
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Sage Interactions - Geometry

goto interact main page

Intersecting tetrahedral reflections FIXME

by Marshall Hampton. Inspired by a question from Hans Schepker of Glass Geometry.

tetrareflect.png

Evolutes

by Pablo Angulo. Computes the evolute of a plane curve given in parametric coordinates. The curve must be parametrized from the interval [0,2pi].

evoluta3.png

Geodesics on a parametric surface

by Antonio Valdés and Pablo Angulo. This example was originally composed of two interacts:

  • - the first allowing the user to introduce a parametric surface, and draw it. - the second drawing a geodesic within the surface.

The separation was so that after the first interact, the geodesic equations were "compiled", thus making the second interact faster. However, in the following there is only one interact, to make sagecell works.

geodesics1.png geodesics2.png

Dimensional Explorer

By Eviatar Bach

Renders 2D images (perspective or spring-layout) and 3D models of 0-10 dimensional hypercubes. It also displays number of edges and vertices.

dimensions.png

Crofton's formula FIXME

by Pablo Angulo. Illustrates Crofton's formula by throwing some random lines and computing the intersection number with a given curve. May use either solve for exact computation of the intersections, or may also approximate the curve by straight segments (this is the default).

crofton4.png

Banchoff-Pohl area

by Pablo Angulo. Computes the Banchoff-Pohl "area enclosed by a spatial curve", by throwing some random lines and computing the linking number with the given curve. Lines not linked to the given curve are displayed in red, linked lines are displayed in green.

banchoff-pohl.png

interact/geometry (last edited 2023-08-30 08:21:15 by pang)