Please consider adding support for AMD, the Asynchronous Module Definition. The AMD plus web pattern seems suitable and it is easy to implement:

(function (root, factory) {
    if (typeof define === 'function' && define.amd) {
        // AMD. Register as an anonymous module.
        define(factory);
    } else {
        // Browser globals
        root.amdWeb = factory(root.b);
    }
}(this, function () {

    // Current Sylvester code

    return {
        Sylvester: Sylvester,
        Vector: Vector,
        Matrix: Matrix,
        Line: Line,
        Plane: Plane,
        $V: $V,
        $M: $M,
        $L: $L,
        $P: $P
    }
}));

There are two cases for Plane.create(), when two arguments are passed and when three arguments are passed.

When two arguments are passed, the documentation and the code are in agreement: the second argument is used as the normal vector for the plane.

However, when three arguments are passed, the documentation and the code are in contradiction. The documentation claims that the second and third arguments should be direction vectors in the plane. However, the code does something different: it assumes that all three arguments are points in the plane, and it takes the cross product of (arg2-arg1) and (arg3-arg1) to compute the normal vector.

Please fix the documentation and code to be in agreement on this issue.

Hello. Great library, thanks for all your work.

I see that the code uses array.map(), which isn't available for IE 8 and older. The docs does not state whether there's polyfill for IE. It would be helpful add a browser compatibility section in readme. Thanks.

Hi there,

just a simple question: do you have a way to get submatrix of other matrix with defined x, y and width and height, for example:

input
var Origin =
[
[ 0, 0, 1, 1, 1]
[0, 0, 1, 1, 1]
[0, 0, 1, 1, 1]
]

I need only part with 1,
var x0 = 2;
var y0 = 1;
var width = 3;
var height = 3;
var result = submatrix(Origin, x0, x0, width, height );

result matrix is:
[
[1,1,1]
[1,1,1]
[1,1,1]
]

JS now have native impl-n of matrices. Lets use it.

This is useful for affine transformations: http://www.math.ucla.edu/~baker/149.1.02w/handouts/i_affine_II.pdf

http://en.wikipedia.org/wiki/Generalized_inverse

Would generally be useful for some computer graphics tasks.

Hello guru,

Is it possible to integrate the ES 7 SIMD APIs into the mathematical JS library?

$M([[2]]).inv()
returns the error:
TypeError: Cannot read property '1' of undefined
in Chrome developer tools inspector.

It should return a matrix of:
[[0.5]] instead.

Please replace all existing <= and >= with Sylvester.precision based operations such as

function leql(operand1, operand2) {
    return (operand1 < operand2) || eql(operand1, operand2);
}

for <=, which would probably solve #6 and other imaginable issues.

I'm working in 2D only but Line.pointClosestTo returns 3D vector with z being 0, can you add Vector.to2D() function that would drop third element of a vector, right now there is Vector.to3D which adds zero, this would remove it. It is problem because when I want to use it later:

Vector.create([2, 0]).subtract(Vector.create([1, 0, 0])) - returns null

In order to make it work I need to use temp variable:
var t = Vector.create([1, 0, 0]);
t = Vector.create([t[0], t[1]]);
Vector.create([2, 0]).subtract(t);

Which is unwieldy but more importantly cannot be chained.

Am I something wrong in below?

LineA : (1,3)(2,9), LineB : (1,6)(2,6) , Correct intersection Point should be (1.5, 6)

var a = sv.Line.create([1,3],[2,9]);
var b = sv.Line.create([1,6],[2,6],);
console.log('intersectionWith : ', a.intersectionWith(b));
But it result
intersectionWith : [3.000000000000011, 12.000000000000052, 0]
intersects : true
pointClosestTo : [3.000000000000011, 12.000000000000052, 0]
reflectionIn :
{ anchor: [-0.800000000000003, 3.600000000000001, -1.1617635945578294e-16],
direction: [0.41216786985544684, 0.9111079228383558, 1.2601095422223854e-17] }

Importing this library breaks standard Math.sign func

Math.sign(0) // 0
require('sylvester')
Math.sign(0) // 1

The link that has this exact text is broken:
"the API documentation"

There is another link to the docs that works tho. Thanks for all your hard work!

I'll do it. I'm currently maintaining a node port with some additional functionality (QR, LU decompositions and SVD)

https://github.com/NaturalNode/node-sylvester

Hi
I think there is a bug in Sylvester, in the toRightTriangular function of sylvester.src.js it is missing declaring j as a local variable.
Currently:
var n = this.elements.length, k = n, i, np, kp = this.elements[0].length, p;
Should be:
var n = this.elements.length, k = n, i, j, np, kp = this.elements[0].length, p;

It is currently modifying any global j variable.

Best regards

PS: did not find your contact address

HI,

I have been using Sylvester as it is posted on the website v 0.1.3. The Unit testing framework I am using reported a global variable "j".

I tracked it down to the function "toRightTriangular" where "j" is used without being declared.

This seems already to have been fixed on the repository, but I am new to GIT, and don't know how to get the latest version.

Thanks Jacob

Hi there,

Would you mind tagging a new release? It looks like the last one was in 2008 so it's missing a bunch of commits.

At the moment, I'm hung up on the fact that the last tagged release has no package.json.

Thanks!

Reading the api documentation for vector, under isAntiparallelTo() method it says: "Returns true iff vector’s direction is exactly opposed to that of the receiver, that is, if the angle between them is π." Wouldn't exactly opposite be π/2?

may be we need a reshape method

Is something like this correct ? Matrix.RotationX(value).add(Matrix.RotationY(value)); How would i go about if i wanted to get the rotation on both axis by a given value ?

Hi, I m having some trouble with 'null' values within a matrix. Is there a way to handle such entries? it would be great to keep them, and not replace these entries by another (numerical) value.

example:
a = [[1,2],[3,4],[null,5]]
$M(a) should deliver sth like:
[1 2
3 4
null 5]

but actually builds a matrix like this:
[1 2
3 4]

best, johsh

$M( [[1]]).det() throws an error. I'd suggest creating a quick return for 1x1 matrices.

Hello expert,

I have discovered the function "Polygon.prototype.scale(k, point)" always scale up/down the polygon in all directions (including X, Y, Z). However, I'd like to scale the polygon in X direction.

Could you please give me a few of algorithm suggestions?

Just a heads up on the http://sylvester.jcoglan.com Sylvester site the link you have for the documentation (http://sylvester.jcoglan.com/docs) is broken.

Thanks for an awesome script!

There is a possibility of Line.Segment.intersectionWith to fail, by trying to access a null object.

Current code:

intersectionWith: function(obj) {
    if (!this.line.intersects(obj)) { return null; }
    var P = this.line.intersectionWith(obj);
    return (this.contains(P) ? P : null);
  }

The problem exists with the value of 'P'. This can be returned as null. Thus when the last line is executed "this.contains(P)" the code will fail, as P is null.

Test Code:

a = Sylvester.Line.Segment.create([600,216], [200, 216])
b = Sylvester.Line.Segment.create([300,616], [200, 216])
a.intersectionWith(b) // returns a valid point
b.intersectionWith(a) // fails! TypeError: Cannot read property 'start' of null

Is there a .d.ts file?

Only vector has inspect method (I use it mostly for debugging), why not add inspect method for other objects (matrix, line, plane).

Posted also on Stack: http://stackoverflow.com/questions/11658338/line-intersections-with-sylvesterjs-did-i-break-my-maths

Am I misusing vectors, possibly? Or did I just forget how to use tangents to indicate a direction? I can't seem to get this intersections to work:

var angle = 45;
var line1 = $L([1,1],[Math.tan(angle * Math.PI/180),Math.tan(angle * Math.PI/180)]); //Should be a 45-degree angle
angle = -45;
var line2 = $L([0,0],[Math.tan(angle * Math.PI/180),Math.tan(angle * Math.PI/180)]); //Should be a -45-degree angle
line1.intersects(line2);
//returns false, should be true, I would think?

Hello expert,

The existing API online documentation (http://sylvester.jcoglan.com/docs.html) is out of date. Therefore, the latest docs update is desirable.

Someone has put Sylvester into a handy npm module: sylvester-es6. It's only a matter a time when the two versions diverge and the documentation no longer matches. Maybe it's time for a major update with incorporation of ES6, NPM and other relevant JS tools.
I'm currently using sylvester-es6 for this.

Is there a Dart version of Sylvester, or is a Dart port planned? Thank you!