math: 雅可比矩阵 黑塞矩阵
雅可比矩阵:一个多元函数的一阶偏导数以一定方式排列成的矩阵
黑塞矩阵:一个多元函数的二阶偏导数以一定方式排列成的矩阵
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雅可比矩阵
定义
在向量分析中,雅可比矩阵是函数的一阶偏导数以一定方式排列成的矩阵,其行列式称为雅可比行列式。
在代数几何中,代数曲线的雅可比行列式表示雅可比簇:伴随该曲线的一个代数群,曲线可以嵌入其中。
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D20/sign=eeee76790155b31998f9857543a9af20/14ce36d3d539b6007bde35cfe250352ac65cb7b1.jpg)
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D23/sign=945dde80ac86c9170c03553ac83d6f8c/060828381f30e924b90ea64947086e061d95f71b.jpg)
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D20/sign=eeee76790155b31998f9857543a9af20/14ce36d3d539b6007bde35cfe250352ac65cb7b1.jpg)
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D23/sign=945dde80ac86c9170c03553ac83d6f8c/060828381f30e924b90ea64947086e061d95f71b.jpg)
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D90/sign=2283bdb348166d223c771994472392ed/9c16fdfaaf51f3dec3f7831c9feef01f3a297904.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D217/sign=2086f4bab9119313c343f8b152390c10/91ef76c6a7efce1beed3f2b2a451f3deb58f65c9.jpg)
。这些函数的偏导数(如果存在)可以组成一个m行n列的矩阵,这个矩阵就是所谓的雅可比矩阵:
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D119/sign=3bf31690b73eb13540c7b3ba9f1fa8cb/7c1ed21b0ef41bd51697d28c5ada81cb38db3d85.jpg)
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D89/sign=ca3962c34c10b912bbc1fbf7c3fd6225/6f061d950a7b02087cdc1a9969d9f2d3572cc8b4.jpg)
,或者
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D90/sign=8dc8c78270cb0a46812287396b63e732/9825bc315c6034a8dfe49df9c013495409237647.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D102/sign=ed2d9df9c01349547a1eec64644f92dd/c2fdfc039245d68867cd97dcafc27d1ed31b24fe.jpg)
这个矩阵的第 i行是由梯度函数的转置表示的
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D20/sign=eeee76790155b31998f9857543a9af20/14ce36d3d539b6007bde35cfe250352ac65cb7b1.jpg)
中的一点,F在 p点可微分,根据高等微积分,
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D35/sign=fa9c3177b30e7bec27da05e42e2e2b9b/b7fd5266d016092468858763df0735fae6cd3421.jpg)
是在这点的导数。在此情况下,
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D35/sign=fa9c3177b30e7bec27da05e42e2e2b9b/b7fd5266d016092468858763df0735fae6cd3421.jpg)
这个线性映射即F在点p附近的最优线性逼近,也就是说当x足够靠近点p时,我们有:
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D184/sign=2534ebbab9119313c343fbb851390c10/9c16fdfaaf51f3dec2f89c1c9feef01f3a29797b.jpg)
实例
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D171/sign=74cd23b2898ba61edbeecc28703597cc/d1160924ab18972b11ff25b2edcd7b899f510a84.jpg)
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D116/sign=bf6ec15e0224ab18e416e53603fae69a/728da9773912b31b5d59e9518d18367adab4e195.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D114/sign=f4d852efd233c895a27e9c7ae5127397/8601a18b87d6277f65d3174023381f30e824fc81.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D80/sign=16f7f78570899e517c8e371442a74501/08f790529822720e2ffec68270cb0a46f21fab91.jpg)
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D521/sign=c6e82799242eb938e86d7af0e46285fe/810a19d8bc3eb135a1f593c3ad1ea8d3fd1f4493.jpg)
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D20/sign=5f8548a6366d55fbc1c671266d22950b/b58f8c5494eef01f433b3cbdebfe9925bc317d9e.jpg)
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D48/sign=a83197503d7adab439d01a4b8bd4bc25/0dd7912397dda144fd1c48cab9b7d0a20cf486b4.jpg)
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D58/sign=88ad5ba525738bd4c021b239a18bb914/96dda144ad345982e0aec1ea07f431adcbef84a5.jpg)
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D99/sign=8de2279bde39b60049ce03bee950cf28/a71ea8d3fd1f41340f2621062e1f95cad1c85eb0.jpg)
![](https://gss0.bdstatic.com/-4o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D89/sign=1fa01b9969d9f2d3241129e6a8ec84d0/203fb80e7bec54e752853e66b2389b504fc26a58.jpg)
![](https://gss0.bdstatic.com/-4o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D416/sign=3f0be76c60600c33f479dfc92c4d5134/ac345982b2b7d0a2589c20e5c0ef76094b369a74.jpg)
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D87/sign=1baa0a9da66eddc422e7b9fc38db73d9/908fa0ec08fa513d33c948a6366d55fbb2fbd962.jpg)
在点
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D46/sign=2a882b6126f5e0feea1888075d603290/faedab64034f78f02da1be8b72310a55b3191c1b.jpg)
的雅可比矩阵是连续且可逆的,则F在点 p的某一邻域内也是可逆的,且有
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D92/sign=0744e39b5c2c11dfdad1b32162278296/b90e7bec54e736d14ab3a87090504fc2d5626921.jpg)
黑塞矩阵(Hessian Matrix),又译作海森矩阵、海瑟矩阵、海塞矩阵等,是一个多元函数的二阶偏导数构成的方阵,描述了函数的局部曲率。黑塞矩阵最早于19世纪由德国数学家Ludwig Otto Hesse提出,并以其名字命名。黑塞矩阵常用于牛顿法解决优化问题,利用黑塞矩阵可判定多元函数的极值问题。在工程实际问题的优化设计中,所列的目标函数往往很复杂,为了使问题简化,常常将目标函数在某点邻域展开成泰勒多项式来逼近原函数,此时函数在某点泰勒展开式的矩阵形式中会涉及到黑塞矩阵。
定义
在工程实际问题的优化设计中,所列的目标函数往往很复杂,为了使问题简化,常常将目标函数在某点邻域展开成泰勒多项式来逼近原函数。
二元函数的黑塞矩阵
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D32/sign=82b43bfca451f3dec7b2bf6695ee39db/d01373f082025aafbbad8dfdf0edab64034f1a6c.jpg)
在
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D52/sign=b3cbbdf201d162d981ee621e10df85f9/7aec54e736d12f2e08fb5d5644c2d5628535680e.jpg)
![](https://gss0.bdstatic.com/-4o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D32/sign=053b500c3b4e251fe6f7e2faa7861346/8601a18b87d6277fda20c00e23381f30e924fcd2.jpg)
在
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D24/sign=bfc5a5dff9d3572c62e29bd88a13834e/9a504fc2d562853550c920179bef76c6a7ef63df.jpg)
点处的泰勒展开式 :
,其中 ,
。二元函数
在
点处的泰勒展开式为:
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D382/sign=d0a2aa8f95510fb37c19719feb33c893/4bed2e738bd4b31cb16e708d8cd6277f9e2ff8b2.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D428/sign=1869518cde62853596e0d323a8ef76f2/cdbf6c81800a19d83f07af7b38fa828ba61e4643.jpg)
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D222/sign=7c0a2ffca451f3dec7b2be66a6eef0ec/c8177f3e6709c93d91d3e9c1943df8dcd10054e7.jpg)
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D571/sign=8ccc6d0c12d8bc3ec20806cdb38ba6c8/1ad5ad6eddc451da6186d4ddbdfd5266d0163290.jpg)
![](https://gss0.bdstatic.com/-4o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D387/sign=bacfd97cd1b44aed5d4eb8ec841d876a/58ee3d6d55fbb2fb7fc18224444a20a44623dc1a.jpg)
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D312/sign=b330f23d50b5c9ea66f305e2e738b622/55e736d12f2eb9381cfbbec4de628535e5dd6f76.jpg)
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D51/sign=de2bc8072a3fb80e08d161d637d12cfb/50da81cb39dbb6fd8da421100224ab18972b370d.jpg)
是
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D61/sign=8fd623ceac86c9170c035138c93d6f52/a08b87d6277f9e2f1d14da3e1430e924b899f3e7.jpg)
在
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D28/sign=c7704b3e90504fc2a65fb70de5dd2518/34fae6cd7b899e51e7edfd2249a7d933c8950da1.jpg)
点处的黑塞矩阵。它是由函数
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D61/sign=8fd623ceac86c9170c035138c93d6f52/a08b87d6277f9e2f1d14da3e1430e924b899f3e7.jpg)
在
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D28/sign=c7704b3e90504fc2a65fb70de5dd2518/34fae6cd7b899e51e7edfd2249a7d933c8950da1.jpg)
点处的二阶偏导数所组成的方阵。
多元函数的黑塞矩阵
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D108/sign=1da428cba41ea8d38e227004af0b30cf/dcc451da81cb39db98a3f826d2160924ab18305a.jpg)
在
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D28/sign=c7704b3e90504fc2a65fb70de5dd2518/34fae6cd7b899e51e7edfd2249a7d933c8950da1.jpg)
点处的泰勒展开式的矩阵形式为:
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D387/sign=4a1e3e17798b4710ca2ffbc4f4cfc3b2/d043ad4bd11373f072bda9a9af0f4bfbfbed0402.jpg)
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D252/sign=0a35da7580d4b31cf43c93beb5d7276f/08f790529822720e4c2b23cc70cb0a46f21fab1b.jpg)
,它是
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D36/sign=5d6306d8bf8f8c54e7d3c3293a29376e/83025aafa40f4bfb09df5e62084f78f0f73618fd.jpg)
在
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D28/sign=c7704b3e90504fc2a65fb70de5dd2518/34fae6cd7b899e51e7edfd2249a7d933c8950da1.jpg)
点处的梯度。
![](https://gss0.bdstatic.com/-4o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D305/sign=5e5b5318a3d3fd1f3209a43a054f25ce/80cb39dbb6fd52660cc6fc22a018972bd4073613.jpg)
为函数
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D36/sign=5d6306d8bf8f8c54e7d3c3293a29376e/83025aafa40f4bfb09df5e62084f78f0f73618fd.jpg)
在
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D28/sign=c7704b3e90504fc2a65fb70de5dd2518/34fae6cd7b899e51e7edfd2249a7d933c8950da1.jpg)
点处的黑塞矩阵
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D16/sign=009823f89225bc312f5d059e5edf3024/aec379310a55b319c6a9744348a98226cffc17b7.jpg)
在点X处的二阶偏导数组成的
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D34/sign=b62492dc8acb39dbc5c06152d116709b/b3fb43166d224f4a4b44852502f790529822d123.jpg)
阶对称矩阵。
对称性
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D16/sign=7fc418f7d2a20cf44290fad97609d939/d53f8794a4c27d1ef45da4b419d5ad6eddc43842.jpg)
在
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D13/sign=8990b495af6eddc422e7b0f838db73d6/54fbb2fb43166d22c82e8fe4442309f79052d261.jpg)
区域内二阶连续可导,那么
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D16/sign=7fc418f7d2a20cf44290fad97609d939/d53f8794a4c27d1ef45da4b419d5ad6eddc43842.jpg)
黑塞矩阵
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D35/sign=fb590b4f49fbfbedd859307a79f0576a/d62a6059252dd42a89c29bdb013b5bb5c8eab8f3.jpg)
在
![](https://gss3.bdstatic.com/7Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D13/sign=8990b495af6eddc422e7b0f838db73d6/54fbb2fb43166d22c82e8fe4442309f79052d261.jpg)
内为对称矩阵
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D16/sign=7fc418f7d2a20cf44290fad97609d939/d53f8794a4c27d1ef45da4b419d5ad6eddc43842.jpg)
的二阶偏导数连续,则二阶偏导数的求导顺序没有区别,即
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D141/sign=72a408d9ab014c081d3b2ca13b7a025b/8644ebf81a4c510f4279676a6259252dd42aa505.jpg)
则对于矩阵
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D35/sign=fb590b4f49fbfbedd859307a79f0576a/d62a6059252dd42a89c29bdb013b5bb5c8eab8f3.jpg)
,有
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D114/sign=1a702e110db30f24319ae802fc94d192/2f738bd4b31c8701c0723796257f9e2f0608fffe.jpg)
,所以
![](https://gss1.bdstatic.com/9vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D35/sign=fb590b4f49fbfbedd859307a79f0576a/d62a6059252dd42a89c29bdb013b5bb5c8eab8f3.jpg)
为对称矩阵。
利用黑塞矩阵判定多元函数的极值
定理
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D108/sign=1da428cba41ea8d38e227004af0b30cf/dcc451da81cb39db98a3f826d2160924ab18305a.jpg)
在点
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D112/sign=82e8f225d654564ee165e03881df9cde/d788d43f8794a4c2b6a2291d05f41bd5ad6e3907.jpg)
的邻域内有二阶连续偏导,若有:
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D201/sign=6b467e0451afa40f38c6c9dd9a65038c/b999a9014c086e060523f67d09087bf40ad1cb79.jpg)
![](https://gss0.bdstatic.com/94o3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D244/sign=5f751422b399a9013f355c3229950a58/bf096b63f6246b604c767a42e0f81a4c510fa288.jpg)
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D108/sign=1da428cba41ea8d38e227004af0b30cf/dcc451da81cb39db98a3f826d2160924ab18305a.jpg)
在
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D112/sign=82e8f225d654564ee165e03881df9cde/d788d43f8794a4c2b6a2291d05f41bd5ad6e3907.jpg)
处是极小值;
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D108/sign=1da428cba41ea8d38e227004af0b30cf/dcc451da81cb39db98a3f826d2160924ab18305a.jpg)
在
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D112/sign=82e8f225d654564ee165e03881df9cde/d788d43f8794a4c2b6a2291d05f41bd5ad6e3907.jpg)
处是极大值;
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D112/sign=82e8f225d654564ee165e03881df9cde/d788d43f8794a4c2b6a2291d05f41bd5ad6e3907.jpg)
不是极值点。
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D112/sign=82e8f225d654564ee165e03881df9cde/d788d43f8794a4c2b6a2291d05f41bd5ad6e3907.jpg)
是“可疑”极值点,尚需要利用其他方法来判定。
实例
![](https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D259/sign=4c279a3e07d79123e4e0937194355917/cf1b9d16fdfaaf5175794b89875494eef01f7a6a.jpg)
的极值。
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D264/sign=92943bc0943df8dca23d8897f91172bf/c995d143ad4bd11391ab820551afa40f4bfb05a6.jpg)
,故该三元函数的驻点是
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D69/sign=f4e5d4388c94a4c20e23e4220ef47929/8b13632762d0f703b3e2a0eb03fa513d2697c5b0.jpg)
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D409/sign=0d9443a0d233c895a27e997be8127397/f9198618367adab4485d2f7480d4b31c8701e473.jpg)
![](https://gss3.bdstatic.com/-Po3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D106/sign=4d715061db160924d825a61be206359b/f703738da97739124897b256f3198618367ae250.jpg)
![](https://gss2.bdstatic.com/9fo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D69/sign=f4e5d4388c94a4c20e23e4220ef47929/8b13632762d0f703b3e2a0eb03fa513d2697c5b0.jpg)
是极小值点,且极小值
![](https://gss1.bdstatic.com/-vo3dSag_xI4khGkpoWK1HF6hhy/baike/s%3D129/sign=039889d3b81c8701d2b6b6e41e7e9e6e/42166d224f4a20a46bc80bf09b529822720ed036.jpg)
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