# First M-step of the AECM algorithm when fitting a mixture of PPCA models.

### Description

Internal function required for fitting a mixture of PPCA models.

### Usage

1 | ```
mstep1(Y, Tau, Pi, mu, g)
``` |

### Arguments

`Y` |
A N x p data matrix. |

`Tau` |
An N x G matrix of posterior group membership probabilities. |

`Pi` |
A g vector of group probabilities. |

`mu` |
A p x g matrix containing the mean for each group. |

`g` |
The number of groups currently being fitted. |

### Details

First M-step of the AECM algorithm when fitting a mixture of PPCA models. An internal function.

### Value

A list containing

`Pi` |
A g vector of group probabilities |

`Mu` |
A p x g matrix each column of which contains a group mean. |

### Note

An internal function.

### Author(s)

Nyamundanda Gift, Isobel Claire Gormley and Lorraine Brennan

### References

Nyamundanda, G., Gormley, I.C. and Brennan, L. (2010) Probabilistic principal components analysis for metabolomic data. Technical report. University College Dublin, Ireland.

### See Also

`mppca.metabol`