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pca() not working as advertised

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Alexander Tarroni
Alexander Tarroni 2016-11-22
评论： Image Analyst 2020-4-4
When consulting the documentation for the pca() function, I tried the following example:
load hald
The ingredients data has 13 observations for 4 variables.
Find the principal components for the ingredients data.
load hald
coeff = pca(ingredients)
coeff =
-0.0678 -0.6460 0.5673 0.5062
-0.6785 -0.0200 -0.5440 0.4933
0.0290 0.7553 0.4036 0.5156
0.7309 -0.1085 -0.4684 0.4844
The rows of coeff contain the coefficients for the four ingredient variables, and its columns correspond to four principal components.
However on my machine, I get this output for the same commands:
load hald
coeff = pca(ingredients)
coeff =
517.7969
67.4964
12.4054
0.2372
Does anyone know why this is happening? I am running the latest version of Matlab r2016b on Ubuntu 16.04

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回答（1 个）

KSSV
KSSV 2016-11-22
Try
[pc,score,latent,tsquare] = princomp(ingredients);
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显示 3更早的评论
XiXi Liu
XiXi Liu 2020-4-4
通过命令: which -all princomp 或者 which -all pca
查看pca/princomp都有哪些路径；
会显示至少两个有该函数的路径，因此造成冲突；
手动删除其中的某个路径，尽量保留Matlab 工具箱的路径。
Image Analyst
Image Analyst 2020-4-4
princomp() was removed from the Statistics and Machine Learning Toolbox in R2019a.
In r2020a:
load hald
coeff = pca(ingredients)
coeff =
-0.0678 -0.64602 0.56731 0.50618
-0.67852 -0.019993 -0.54397 0.49327
0.029021 0.75531 0.40355 0.51557
0.73087 -0.10848 -0.4684 0.48442

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