Package 'parmigene'

Title: Parallel Mutual Information Estimation for Gene Network Reconstruction
Description: Parallel estimation of the mutual information based on entropy estimates from k-nearest neighbors distances and algorithms for the reconstruction of gene regulatory networks (Sales et al, 2011 <doi:10.1093/bioinformatics/btr274>).
Authors: Gabriele Sales [aut, cre], Chiara Romualdi [aut]
Maintainer: Gabriele Sales <[email protected]>
License: AGPL-3
Version: 1.1.1
Built: 2024-11-21 06:52:31 UTC
Source: CRAN

Help Index


Algorithm for the Reconstruction of Accurate Cellular Networks

Description

A function that implements the ARACNE algorithm for the reconstruction of gene interaction networks (additive model).

Usage

aracne.a(mi, eps=0.05)

Arguments

mi

matrix of the mutual information.

eps

a positive numeric value used to remove the weakest edge of each triple of nodes.

Details

This algorithm considers each triple of edges independently and removes the weakest one if

MI(i;j)<MI(j;k)εMI(i;j) < MI(j;k) - \varepsilon

and

MI(i;j)<MI(i;k)εMI(i;j) < MI(i;k) - \varepsilon

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

Value

A square weighted adjacency matrix of the inferred network.

References

Adam A. Margolin, Ilya Nemenman, Katia Basso, Chris Wiggins, Gustavo Stolovitzky, Riccardo Dalla Favera, and Andrea Califano. Aracne : An algorithm for the reconstruction of gene regulatory networks in a mammalian cellular context. BMC Bioinformatics, 2006.

See Also

aracne.m

clr

mrnet

Examples

mat <- matrix(rnorm(1000), nrow=10)
mi  <- knnmi.all(mat)
grn <- aracne.a(mi, 0.05)

Algorithm for the Reconstruction of Accurate Cellular Networks

Description

A function that implements the ARACNE algorithm for the reconstruction of gene interaction networks (multiplicative model).

Usage

aracne.m(mi, tau=0.15)

Arguments

mi

matrix of the mutual information.

tau

a positive numeric value used to remove the weakest edge of each triple of nodes.

Details

This algorithm considers each triple of edges independently and removes the weakest one if

MI(i;j)<MI(j;k)(1τMI(i;j) < MI(j;k) * (1 - \tau

and

MI(i;j)<MI(i;k)(1τ)MI(i;j) < MI(i;k) * (1 - \tau)

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

Value

A square weighted adjacency matrix of the inferred network.

References

Adam A. Margolin, Ilya Nemenman, Katia Basso, Chris Wiggins, Gustavo Stolovitzky, Riccardo Dalla Favera, and Andrea Califano. Aracne : An algorithm for the reconstruction of gene regulatory networks in a mammalian cellular context. BMC Bioinformatics, 2006.

See Also

aracne.a

clr

mrnet

Examples

mat <- matrix(rnorm(1000), nrow=10)
mi  <- knnmi.all(mat)
grn <- aracne.m(mi, 0.15)

Context Likelihood or Relatedness Network

Description

A function that infers the interaction network using the CLR algorithm.

Usage

clr(mi)

Arguments

mi

matrix of the mutual information.

Details

CLR computes the score

sqrt(zi2+zj2)sqrt(z_i^2 + z_j^2)

for each pair of variables i,ji, j, where

zi=max(0,(I(Xi;Xj)mean(Xi))/sd(Xi))z_i = max(0, ( I(X_i;X_j)-mean(X_i) ) / sd(X_i))

and mean(Xi)mean(X_i) and sd(Xi)sd(X_i) are the mean and the standard deviation of the mutual information values I(Xi;Xk)I(X_i;X_k) for all k=1,,nk=1,\ldots,n.

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

Value

A square weighted adjacency matrix of the inferred network.

References

Jeremiah J. Faith, Boris Hayete, Joshua T. Thaden, Ilaria Mogno, Jamey Wierzbowski, Guillaume Cottarel, Simon Kasif, James J. Collins, and Timothy S. Gardner. Large-scale mapping and validation of escherichia coli transcriptional regulation from a compendium of expression profiles. PLoS Biology, 2007.

See Also

aracne.a

aracne.m

mrnet

Examples

mat <- matrix(rnorm(1000), nrow=10)
mi  <- knnmi.all(mat)
grn <- clr(mi)

Parallel Mutual Information Estimation

Description

A function to perform a parallel estimation of the mutual information of vectors x and y using entropy estimates from K-nearest neighbor distances.

Usage

knnmi(x, y, k=3, noise=1e-12)

Arguments

x

a numeric vector.

y

a numeric vector with the same length of x.

k

the number of nearest neighbors to be considered to estimate the mutual information. Must be less than the number of elements of x.

noise

the magnitude of the random noise added to break ties.

Details

The function adds a small random noise to the data in order to break ties due to limited numerical precision.

By default, the function uses all available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

References

Kraskov, Alexander and Stogbauer, Harald and Grassberger, Peter. Estimating mutual information. Phys. Rev. E, 2004.

See Also

knnmi.cross

knnmi.all

Examples

x <- rnorm(100)
y <- rnorm(100)
knnmi(x, y, 5)

Parallel Mutual Information Estimation Between All Matrix Rows

Description

A function that computes the mutual information between all pairs of rows of matrix mat using entropy estimates from K-nearest neighbor distances.

Usage

knnmi.all(mat, k=3, noise=1e-12)

Arguments

mat

a numeric matrix (for the reconstruction of gene regulatory networks, genes on rows and samples on columns).

k

the number of nearest neighbors to consider to estimate the mutual information. Must be less than the number of columns of mat.

noise

the magnitude of the random noise added to break ties.

Details

The function adds a small random noise to the data in order to break ties due to limited numerical precision.

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

References

Kraskov, Alexander and Stogbauer, Harald and Grassberger, Peter. Estimating mutual information. Phys. Rev. E, 2004.

See Also

knnmi

knnmi.cross

Examples

mat <- matrix(rnorm(1000), nrow=10)
knnmi.all(mat, 5)

Parallel Mutual Information Estimation Between the Rows of Two Matrices

Description

A function that estimates the mutual information between all pairs of rows of matrices mat1 and mat2 using entropy estimates from K-nearest neighbor distances.

Usage

knnmi.cross(mat1, mat2, k=3, noise=1e-12)

Arguments

mat1

a numeric matrix (for the reconstruction of gene regulatory networks, genes on rows and samples on columns).

mat2

a numeric matrix with the same number of columns as mat1.

k

the number of nearest neighbors to consider to estimate the mutual information. Must be less than the number of columns of mat1.

noise

the magnitude of the random noise added to break ties.

Details

The function adds a small random noise to the data in order to break ties due to limited numerical precision.

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

References

Kraskov, Alexander and Stogbauer, Harald and Grassberger, Peter. Estimating mutual information. Phys. Rev. E, 2004.

See Also

knnmi

knnmi.all

Examples

mat1 <- matrix(rnorm(1000), nrow=10)
mat2 <- matrix(rnorm(1000), nrow=10)
knnmi.cross(mat1, mat2, 5)

Maximum Relevance Minimum Redundancy

Description

A function that infers the interaction network using the MRNET algorithm.

Usage

mrnet(mi)

Arguments

mi

matrix of the mutual information.

Details

The MRNET approach starts by selecting the variable XiX_i having the highest mutual information with the target Y.

Then, it repeatedly enlarges the set of selected variables SS by taking the XkX_k that maximizes

I(Xk;Y)mean(I(Xk;Xi))I(X_k;Y) - mean(I(X_k;X_i))

for all XiX_i already in S.

The procedure stops when the score becomes negative.

By default, the function uses all the available cores. You can set the actual number of threads used to N by exporting the environment variable OMP_NUM_THREADS=N.

Value

A square weighted adjacency matrix of the inferred network.

References

H. Peng, F.long and C.Ding. Feature selection based on mutual information: Criteria of max-dependency, max relevance and min redundancy. IEEE transaction on Pattern Analysis and Machine Intelligence, 2005.

See Also

aracne.a

aracne.m

clr

Examples

mat <- matrix(rnorm(1000), nrow=10)
mi  <- knnmi.all(mat)
grn <- mrnet(mi)