WOLFRAM

WindingCount
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WindingCount

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WindingCount[contour,p]

gives the count of the number of times a closed curve winds around a point p.

Details and Options

  • WindingCount is also known as winding number.
  • WindingCount is typically used to define a polygon from self-intersecting closed curves.
  • A counterclockwise revolution has a value 1 and a clockwise revolution has a value -1. For several contours, the number of revolutions around p is the sum of the number of revolutions for each contour.
  • The closed curve contour is typically a collection of line segments Line[{{p1,p2},,{pn-1,pn},{pn,p1}}] and must lie in a plane.
  • For a polygon poly, WindingCount[poly,p] gives the number of times the polygon boundary curves wind around the point p.

Examples

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Basic Examples  (1)Summary of the most common use cases

Count how many times a closed curve winds around a point:

Out[2]=2
Out[3]=3

Scope  (2)Survey of the scope of standard use cases

Count how many times a closed curve winds around a point:

Out[2]=2
Out[3]=3

Count how many times a polygon boundary curve winds around a point:

Out[2]=2
Out[3]=3

Applications  (2)Sample problems that can be solved with this function

Find the polygon density of regular star polygons:

Out[3]=3
Out[4]=4

Color points by the winding count of the point around the given contour:

Out[4]=4

Properties & Relations  (1)Properties of the function, and connections to other functions

CrossingCount is an alternate count function:

Out[20]=20

Possible Issues  (1)Common pitfalls and unexpected behavior

A polygon boundary curve is always given in the counterclockwise orientation with no overlapping:

Out[21]=21

The winding count:

Out[22]=22
Out[25]=25
Wolfram Research (2019), WindingCount, Wolfram Language function, https://reference.wolfram.com/language/ref/WindingCount.html.
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Wolfram Research (2019), WindingCount, Wolfram Language function, https://reference.wolfram.com/language/ref/WindingCount.html.

Text

Wolfram Research (2019), WindingCount, Wolfram Language function, https://reference.wolfram.com/language/ref/WindingCount.html.

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Wolfram Research (2019), WindingCount, Wolfram Language function, https://reference.wolfram.com/language/ref/WindingCount.html.

CMS

Wolfram Language. 2019. "WindingCount." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/WindingCount.html.

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Wolfram Language. 2019. "WindingCount." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/WindingCount.html.

APA

Wolfram Language. (2019). WindingCount. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WindingCount.html

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Wolfram Language. (2019). WindingCount. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/WindingCount.html

BibTeX

@misc{reference.wolfram_2024_windingcount, author="Wolfram Research", title="{WindingCount}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/WindingCount.html}", note=[Accessed: 08-January-2025 ]}

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@misc{reference.wolfram_2024_windingcount, author="Wolfram Research", title="{WindingCount}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/WindingCount.html}", note=[Accessed: 08-January-2025 ]}

BibLaTeX

@online{reference.wolfram_2024_windingcount, organization={Wolfram Research}, title={WindingCount}, year={2019}, url={https://reference.wolfram.com/language/ref/WindingCount.html}, note=[Accessed: 08-January-2025 ]}

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@online{reference.wolfram_2024_windingcount, organization={Wolfram Research}, title={WindingCount}, year={2019}, url={https://reference.wolfram.com/language/ref/WindingCount.html}, note=[Accessed: 08-January-2025 ]}