- 注册时间
- 2009-6-9
- 最后登录
- 1970-1-1
- 威望
- 星
- 金币
- 枚
- 贡献
- 分
- 经验
- 点
- 鲜花
- 朵
- 魅力
- 点
- 上传
- 次
- 下载
- 次
- 积分
- 19898
- 在线时间
- 小时
|
发表于 2019-12-20 19:28:45
|
显示全部楼层
很奇怪,用同样方法计算111#,也没得到mathe的图样,不知mathe能否指点一下?
由t^2-t-1=0,得到t=1.618033988和t=-0.6180339880
下面选择t=-0.6180339880计算得到;
[[A, 0., 1., 1.], [B, -0.3819660120, 0.500000000000000, 1.], [C, -0.2360679760, 0.072949018000000, 1.], [D, -2.2360679760, -0.309016994000000, 1.], [E, 0.3819660120, 0.309016994000000, 1.], [F, 1., 0., 1.], [G, 1., 1.30901699400000, 1.], [H, 0.2360679760, 0.309016994000000, 1.], [I, -0.6180339880, 0.500000000000000, 1.], [J, 0., 0.190983006000000, 1.], [K, 1., 0.309016994000000, 0.], [L, 1., -0.309016994000000, 0.], [M, -1., -0.309016994000000, 1.], [N, -0.2360679760, 0.690983006000000, 1.], [O, -0.6180339880, 0.809016994000000, 1.], [P, -0.6180339880, 0., 1.], [Q, 0.3819660120, 0.190983006000000, 1.], [R, 0.6180339880, 0.190983006000000, 1.], [S, -0.2360679760, 0.309016994000000, 1.], [T, 0., 0., 1.], [U, 0., 1., 0.], [V, 1., 0., 0.], [W, 1., -0.309016994000000, 1.], [X, 0.3819660120, 0.500000000000000, 1.]]
除掉无穷远点K, L, U, V ,画图得到:
按照楼上的计算方法,选择四个点W,U,T,X做射影变换(取变换后WUT构成三角形的顶点,边长为1,X为正三角形的中心)
即W[1., -0.309016994000000, 1.]->[0,sqrt(3)/3,1], U[ 0., 1., 0.]->[-1/2,-sqrt(3)/6,1] , T[0., 0., 1.]->[1/2,-sqrt(3)/6,1] , X[0.3819660120, 0.500000000000000, 1.]->[0,0,1]
求得射影变换矩阵J1为: [[-0.6545084975, -0.5000000000, 0.5000000005], [1.133641970, -0.2886751347, -0.2886751351], [0.9270509787, 1.000000000, 1.000000001]])
注:楼下mathe得到的变换矩阵J2为 [[0.3530056650, 0.2696723314, -0.2696723318], [-0.6114237460, 0.1556953931, 0.1556953933], [-0.4999999974, -0.5393446628, -0.5393446636]];
J1,J2若将每行都化为z=1,就是一样均为 [[-1.309016994, -0.9999999988, 1], [-3.927050974, 0.9999999986, 1], [0.9270509774, 0.9999999986, 1]]
由J1射影变换得到
[2.50000020560093*10^(-10), -0.288675134755662, A], [0.436338998334175, -0.755761313617648, B], [0.723606792750855, -0.675973464288759, C], [-1.53262380618613, 1.97860882314602, D], [0.0574171211872823, 0.0331497903437648, E], [-0.0801787283406760, 0.438476638034528, F], [-0.250000000177685, 0.144337566957350, G], [0.125000001192225, -0.0721687853002482, H], [0.706011326427899, -1.22284748665600, I], [0.339642543279377, -0.288675134793473, J], [-0.654508499830173, 0.844966838960361, K], [-0.809017000485346, 1.97860881867382, L], [-5.54508511075584, 5.64715142478797, M], [0.209910634904626, -0.513377387649850, N], [0.404508496175841, -0.989304399716518, O], [2.11803396725287, -2.31659551579066, P], [0.0999999997827559, 0.0577350267694893, Q], [3.45924335493919*10^(-10), 0.202287890613122, R], [0.458644086862735, -0.592106968939316, S], [0.500000000000000, -0.288675134811325, T], [-0.500000000000000, -0.288675134700000, U], [-0.706011333290230, 1.22284749819228, V], [6.86155565604419*10^(-17), 0.577350269230219, W], [-5.94287545476067*10^(-11), -7.18818497189416*10^(-11), X]
画图显示比较杂乱,肯定是哪里出了问题??点 [-5.54508512863216, 5.64715144008720, M]比较异类离的较远,难道是因为选择作变换的四个点(WUTX)中有一个无穷远点U造成的??? |
-
|