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| [[File:Julia immediate basin 1 3.png|right|thumb|Attracting period-3 cycle and its immediate basin of attraction for a certain parametrization of ''f''(''z'') = ''z''<sup>2</sup> + ''c''. The three darkest points are the points of the 3-cycle, which lead to each other in sequence, and iteration from any point in the basin of attraction leads to (usually asymptotic) convergence to this sequence of three points.]] | | [[File:Julia immediate basin 1 3.png|right|thumb|Attracting period-3 cycle and its immediate basin of attraction for a certain parametrization of ''f''(''z'') = ''z''<sup>2</sup> + ''c''. The three darkest points are the points of the 3-cycle, which lead to each other in sequence, and iteration from any point in the basin of attraction leads to (usually asymptotic) convergence to this sequence of three points.]] |
− | [[资料图:茱莉亚立即盆地1 3.png |右|拇指|吸引周期-3旋回及其对“f”(“z”)参数化的直接吸引盆地。三个最暗的点是3个循环的点,它们按顺序相互连接,从吸引盆地中的任何点迭代会导致(通常是渐进的)收敛到这三个点的序列。]] | + | [[资料图:茱莉亚立即盆地1 3.png |右|拇指|吸引周期-3旋回及其对“f”(“z”)参数化的直接吸引域。三个最暗的点是3循环的点,它们按顺序相互连接,从吸引域中的任何点迭代会导致(通常是渐进的)收敛到这三个点的序列。]] |
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| Attracting period-3 cycle and its immediate basin of attraction for a certain parametrization of f(z) = z<sup>2</sup> + c. The three darkest points are the points of the 3-cycle, which lead to each other in sequence, and iteration from any point in the basin of attraction leads to (usually asymptotic) convergence to this sequence of three points. | | Attracting period-3 cycle and its immediate basin of attraction for a certain parametrization of f(z) = z<sup>2</sup> + c. The three darkest points are the points of the 3-cycle, which lead to each other in sequence, and iteration from any point in the basin of attraction leads to (usually asymptotic) convergence to this sequence of three points. |
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− | f(z) = z<sup>2</sup> + c的某一特定参数的吸引3-周期循环及其直接吸引域。最暗的三个点是3-周期循环的点,它们依次相向,从吸引域中的任何一点迭代都会导致(通常是渐近的)收敛到这三个点的序列。 | + | f(z) = z<sup>2</sup> + c的某一特定参数的吸引3-周期循环及其直接吸引池。最暗的三个点是3-周期循环的点,它们依次相向,从吸引域中的任何一点迭代都会导致(通常是渐近的)收敛到这三个点的序列。 |
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| <math> f(t,(x,v))=(x+tv,v).\ </math> | | <math> f(t,(x,v))=(x+tv,v).\ </math> |
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− | F (t,(x,v) = (x + tv,v) | + | F (t,(x,v)) = (x + tv,v) |
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| * ''A'' is ''forward invariant'' under ''f'': if ''a'' is an element of ''A'' then so is ''f''(''t'',''a''), for all ''t'' > 0. | | * ''A'' is ''forward invariant'' under ''f'': if ''a'' is an element of ''A'' then so is ''f''(''t'',''a''), for all ''t'' > 0. |
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− | *“A”是“f”下的“前向不变”:如果“A”是“A”的元素,则“f”(“t”,“A”)也是,对于所有“t”>0。 | + | *“A”是“f”下的“前向不变”:如果“A”是“A”的元素,则对于所有“t”>0,“f”(“t”,“A”)也是。 |
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| * There exists a [[Neighbourhood (mathematics)|neighborhood]] of ''A'', called the '''basin of attraction''' for ''A'' and denoted ''B''(''A''), which consists of all points ''b'' that "enter ''A'' in the limit ''t'' → ∞". More formally, ''B''(''A'') is the set of all points ''b'' in the phase space with the following property: | | * There exists a [[Neighbourhood (mathematics)|neighborhood]] of ''A'', called the '''basin of attraction''' for ''A'' and denoted ''B''(''A''), which consists of all points ''b'' that "enter ''A'' in the limit ''t'' → ∞". More formally, ''B''(''A'') is the set of all points ''b'' in the phase space with the following property: |
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| Since the basin of attraction contains an open set containing A, every point that is sufficiently close to A is attracted to A. The definition of an attractor uses a metric on the phase space, but the resulting notion usually depends only on the topology of the phase space. In the case of R<sup>n</sup>, the Euclidean norm is typically used. | | Since the basin of attraction contains an open set containing A, every point that is sufficiently close to A is attracted to A. The definition of an attractor uses a metric on the phase space, but the resulting notion usually depends only on the topology of the phase space. In the case of R<sup>n</sup>, the Euclidean norm is typically used. |
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− | 由于吸引盆包含一个含有 a 的开集合,所以每一个足够接近 a 的点都会被 a 吸引。吸引子的定义使用了相空间上的一个度量,但得到的结果通常只依赖于相空间的拓扑结构。在R<sup>n</sup>的情况下,通常使用<font color="#ff8000"> 欧氏范数Euclidean norm</font>。
| + | 由于吸引域包含一个含有 a 的开集合,所以每一个足够接近 a 的点都会被 a 吸引。吸引子的定义使用了相空间上的一个度量,但得到的结果通常只依赖于相空间的拓扑结构。在R<sup>n</sup>的情况下,通常使用<font color="#ff8000"> 欧氏范数Euclidean norm</font>。 |
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| Many other definitions of attractor occur in the literature. For example, some authors require that an attractor have positive measure (preventing a point from being an attractor), others relax the requirement that B(A) be a neighborhood. | | Many other definitions of attractor occur in the literature. For example, some authors require that an attractor have positive measure (preventing a point from being an attractor), others relax the requirement that B(A) be a neighborhood. |
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− | <font color="#ff8000"> 吸引子</font>的许多其他定义出现在文献中。例如,一些作者要求<font color="#ff8000"> 吸引子</font>具有正测度(防止一个点成为吸引子) ,另一些作者放松了 B(A)是一个邻域的要求。 | + | 在文献中有<font color="#ff8000"> 吸引子</font>的许多其他定义出现。例如,一些作者要求<font color="#ff8000"> 吸引子</font>具有正测度(防止一个点成为吸引子) ,另一些作者放松了 B(A)是一个邻域的要求。 |
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| == Types of attractors 吸引子的类型== | | == Types of attractors 吸引子的类型== |